GAS-FIRED AIR HEATERS MEC - MEC C SERIES Models 25 - 30 - … · 2004. 4. 16. · GAS-FIRED AIR...

GAS-FIRED AIR HEATERSMEC - MEC C SERIES

Models 25 - 30 - 35 - 50 - 57 - 85

Technical information

This manual is divided into three sections:

- SECTION 1 - GENERAL INFORMATIONIt contains all the information relative to the description of the air heaters and their technical features

- SECTION 2 - TECHNICAL INFORMATION FOR THE INSTALLERIt contains all the instructions and prescriptions that the technical installer must comply with to ensureeffective plant operation

- SECTION 3 - USER OPERATING AND MAINTENANCE INSTRUCTIONSThe section is reserved for the user and contains all the information needed to use the appliancecorrectly and to perform periodic tests

Important notes:

1 - To use the appliance correctly and safely, the installer, the user and the maintenance man, for theirrespective competencies, must comply with what is indicated in this manual.

2 - The word WARNING! is followed by information which, because of its importance, must be carefullyobserved and for which non-compliance may damage the appliance and/or reduce operating safety.

3 - The paragraphs written with bold characters contain important information, warnings orrecommendations which should be carefully considered.

4 - The technical data, styling characteristics, components and accessories reported in this manual arenot binding. Accorroni S.r.l. reserves the right to make changes, at any time, that are considerednecessary to improve the product.

5 - The lawful references, standards or technical rules mentioned in this manual are presented merelyfor the sake of information and should be considered valid as of the date this manual is printed, asindicated on the last page. If new regulations or amendments to current laws go into effect, this willnot obligate Accorroni S.r.l. in any way with regard to others.

6 - Accorroni S.r.l. is responsible for ensuring that its product conforms to the laws, directives andconstruction standards in force at the time the product is sold. Knowledge and compliance with legalregulations and standards regarding plant design, installation, operation and maintenance are theexclusive responsibility, for the respective competencies, of the designer, installer and user.

SUMMARY

SECTION 1 - GENERAL INFORMATION page

1. PRINCIPAL CHARACTERISTICS ............................................................................................... 41.1 Appliance classification ................................................................................................................. 41.2 Certification - EC marking ............................................................................................................. 41.3 Functional description ................................................................................................................... 41.4 Construction characteristics ......................................................................................................... 51.5 Package contents .......................................................................................................................... 51.6 Accessories supplied on request ................................................................................................. 51.7 Fields of use ................................................................................................................................... 61.8 Dimensions ..........................................................................MEC series ..................................... 71.9 Dimensions ..........................................................................MEC C series ............................... 101.10 Exploded view.............................................................................................................................. 131.11 Wiring diagram ............................................................................................................................ 171.12 Technical data table .................................................................................................................... 18

2. CONTROL AND SAFETY DEVICES ......................................................................................... 192.1 Control device .............................................................................................................................. 192.2 Gas unit ........................................................................................................................................ 192.3 Differential pressure switch ........................................................................................................ 192.4 Fan thermostat............................................................................................................................. 202.5 Safety thermostat ........................................................................................................................ 20

SECTION 2 - TECHNICAL INFORMATION FOR THE INSTALLER

3. PRECAUTIONS........................................................................................................................... 213.1 Gas Safety Regulations .............................................................................................................. 213.2 Related documents ..................................................................................................................... 213.3 Transport and handling ............................................................................................................... 213.4 Data check ................................................................................................................................... 213.5 Using the instructions .................................................................................................................. 21

4. INSTALLATION ........................................................................................................................... 214.1 Location ........................................................................................................................................ 214.2 Minimum heights and distances ................................................................................................. 224.3 Air intake and flue exhaust ducts ............................................................................................... 234.4 Installation operations ................................................................................................................. 25

5. START-UP ................................................................................................................................... 265.1 Tests ............................................................................................................................................. 265.2 Ignition .......................................................................................................................................... 275.3 Useful information ....................................................................................................................... 28

6. GAS TYPE CHANGE .................................................................................................................. 286.1 Switching from gas in the second group to gas in the third group .......................................... 286.2 Switching from gas in the third group to gas in the second group .......................................... 29

7. OPERATING DEFECTS ............................................................................................................. 307.1 Preliminary tests .......................................................................................................................... 307.2 Possible defects .......................................................................................................................... 30

8. REPLACING PARTS .................................................................................................................. 328.1 Control equipment ....................................................................................................................... 338.2 Fuse .............................................................................................................................................. 338.3 Gas solenoid valves .................................................................................................................... 338.4 Differential pressure switch ........................................................................................................ 338.5 Control thermostat of the convection fan(s) .............................................................................. 348.6 Safety limit thermostat ................................................................................................................ 348.7 Electrodes .................................................................................................................................... 348.8 Second burner ignition transformer ...................................- Model 85 ..................................... 358.9 Flue exhaust fan .......................................................................................................................... 358.10 Convection fan ............................................................................................................................. 36

9. PERIODIC MAINTENANCE OPERATIONS ............................................................................. 379.1 User information .......................................................................................................................... 379.2 Yearly inspection ......................................................................................................................... 37

10. HEALTH AND SAFETY STATEMENT ...................................................................................... 3810.1 General......................................................................................................................................... 3810.2 Cautionary note ........................................................................................................................... 3810.3 Miscellaneous .............................................................................................................................. 3810.4 Thermostat ................................................................................................................................... 3810.5 Electrolytic capacitor ................................................................................................................... 38

SECTION 3 - USER OPERATING AND MAINTENANCE INSTRUCTIONS

11. START-UP ................................................................................................................................... 3911.1 First firing and testing .................................................................................................................. 39

11.2 Tests ............................................................................................................................................. 3911.3 Ignition .......................................................................................................................................... 39

11.4 Shutdown ..................................................................................................................................... 3911.5 Summer ventilation...................................................................................................................... 40

12. PLANT MAINTENANCE ............................................................................................................. 4012.1 Routine maintenance to be performed by the user .................................................................. 4012.2 Annual air heater inspection ....................................................................................................... 40

FIGURE SUMMARYFig. no. ............................................................................................................................................... page

1 Dimensions ..........................................................................- MEC 25 - 30 - 35 ......................... 72 Dimensions ..........................................................................- MEC 50 - 57 ................................. 83 Dimensions ..........................................................................- MEC 85 ......................................... 94 Dimensions ..........................................................................- MEC C 25 - 30 - 35 .................... 105 Dimensions ..........................................................................- MEC C 50 - 57 ........................... 116 Dimensions ..........................................................................- MEC C 85 ................................... 127 Exploded view......................................................................- Models 25 - 30 - 35 .................... 138 Exploded view......................................................................- Models 50 - 57 ........................... 149 Exploded view......................................................................- Model 85 ..................................... 15

10 Wiring diagram ....................................................................- MEC 25 - 30 - 35 - 50 - 57 ........ 1711 Control device .............................................................................................................................. 1912 Gas unit ................................................................................- Models 25 - 30 - 35 .................... 1913 Gas unit ................................................................................- Models 50 - 57 - 85 .................... 1914 Differential pressure switch ........................................................................................................ 1915 Fan thermostat ............................................................................................................................ 2016 Safety thermostat ........................................................................................................................ 2017 Position indications ...................................................................................................................... 2218 Minimum distances...................................................................................................................... 2319 Type C

12 installation ..................................................................................................................... 24

20 Type C52

installation ..................................................................................................................... 2421 Type B

22 installation ..................................................................................................................... 24

22 Connection of different units to one timer ................................................................................. 2623 Remote-control panel .................................................................................................................. 2724 Gas injector replacement ....................................................- Models 25 - 30 - 35 .................... 2825 Gas injector replacement ....................................................- Models 50 - 57 ........................... 2926 Gas injector replacement ....................................................- Model 85 ..................................... 2927 Gas injector installation ............................................................................................................... 3028 Control equipment replacement ................................................................................................. 3329 Gas unit coil replacement ...................................................- Models 25 - 30 - 35 .................... 3330 Gas unit coil replacement ...................................................- Models 50 - 57 - 85 .................... 3331 Pressure switch replacement ..................................................................................................... 3432 Fan thermostat replacement ...................................................................................................... 3433 Safety thermostat replacement .................................................................................................. 3434 Electrode positioning ...........................................................- Models 25 - 30 - 35 .................... 3435 Electrode positioning ...........................................................- Models 50 - 57 ........................... 3536 Electrode positioning ...........................................................- Model 85 ..................................... 3537 Ignition transformer replacement - 2nd burner .................- Model 85 ..................................... 3538 Flue exhaust replacement ..................................................- Models 25 - 30 - 35 - 50 - 57 .... 3539 Flue exhaust replacement ..................................................- Model 85 ..................................... 3640 Fan replacement ..................................................................- MEC ............................................ 3641 Fan replacement ..................................................................- MEC C ........................................ 3642 Cleaning the exchanger .............................................................................................................. 3743 Remote-control panel .................................................................................................................. 39

SECTION 1 - GENERAL INFORMATION

certificate” in conformity with EEC Directive 90/396 and with reference to the harmonisedEuropean standard prEN 1020. Attaching theCE marking shown below also guarantees thatthe appliance conforms with EEC directive 73/23 (“Low voltage”) and EEC directive 89/336(“Electromagnetic compatibility”).

1.3 FUNCTIONAL DESCRIPTION

The MEC warm air heater consists basically of aheat exchanger operating between thecombustion products of a gas burner and the airflow exerted by one (models 25-30-35), two(models 50-57) or three fans (model 85).

The air is drawn from the room by the fan(s),conveyed to the exchanger which, operating tothe rated temperature by the burner, transfersheat to the air.

With the MEC series appliances, the warm air isinserted directly into the environment and theflow can be directed using the louvers, while withthe MEC C series appliances, the warm air canbe distributed in the rooms by using specialducts and delivery outlets.

Fan operation is controlled by a thermostat: toprevent cold air from entering the environment,the fan begins operating after the burner isignited. Instead, the fan is stopped with a shortdelay with respect to when the burner isextinguished, to allow the exchanger to cool offgradually.

In case of malfunction or if the fan(s) does(do)not turn on and the exchanger overheats, asafety thermostat trips and cuts off the gas flowto the burner.The combustion products are exhaustedoutdoors by a centrifugal fan installed after thecombustion circuit. If the ducts are obstructed orthe fan does not work, a differential pressureswitch cuts off the gas flow to the burner.

Air heater operation can be controlled by a roomthermostat (not supplied) or from a remote-

1. PRINCIPAL CHARACTERISTICS1.1 APPLIANCE CLASSIFICATION

These appliance are defined as “Gas-fired airheaters with an atmospheric burner equippedwith a fan in the combustion circuit”.

In addition, they are classified according toharmonised European standards EN 437 andprEN 1020 into:

category - according to the types of gas, at thedifferent supply pressures, that they can use;

type - according to the possible methods to exhaustthe combustion productions (see also 4.3.1).

1) Category II2H3+

the air heater is suitable to use gas that belongsto two families. The atmospheric burner can befed with the gas from the second group (naturalgas - group H) and the gas from the third group(butane and propane at the two pressure ratings28-30 and 37 mbar)

2) Type C12

The combustion circuit is sealed with respect tothe environment in which it is installed and thecombustion air supply and combustion productexhaust lines are connected outside the room bymeans of ducts which pass directly through theoutside wall of the room, including terminalswithin a square with a 50 cm side.

3) Type C52

The combustion circuit is hermetically sealedwith respect to the environment in which it isinstalled and the combustion air supply andcombustion product exhaust lines are connectedoutside the room by means of ducts with terminalslocated also on walls not in the room. Thecombustion products can be exhausted alsowith a special duct on the roof of the building.

4) Type B22

Combustion air intake is performed within theenvironment, while the combustion products areexhausted through a duct that passes directlythrough an external wall or on the roof of abuilding.

1.2 CERTIFICATION - EC MARKING

The MEC air heaters, as previously describedand classified, have obtained the “CE type test

0051

control panel (supplied on request). With theremote-control panel the air heater can be used,during the summer, just to ventilate the room,excluding the burner operation.

1.4 CONSTRUCTION CHARACTERISTICS

The casing is built with epoxy-powder paintedsteel plate to guarantee extended service life.

The air delivery opening is located in the front ofthe appliance along with the horizontal louverswhich can be adjusted manually (MEC), or witha special configuration to connect ducts (MECC). The exchanger is equipped with the ventilationthermostat and the safety thermostat bulb.

The rear of the appliance includes the following:

- the axial (MEC) or centrifugal (MEC C)convection fan(s) with safety grille

- the connectors to attach the combustion airinlet and combustion product exhaust ducts

- the gas supply connector- the electric cable entries

The following is installed in a service door on theright side:- the electric board with relative wiring- the burner control device- the appliance reset button with relative

illuminated signal- the safety thermostat- the differential pressure switch- the gas unit- the flue exhaust fan (except model 85)

Instead, only for the model 85, the service dooron the left side contains the following:- the ignition transformer, with relative electrode,

serving the second burner- the gas connector and header with injectors to

feed the second burner

The interior of the appliance includes:- the combustion chamber and the stainless

steel heat exchangers- the flue exhaust fan (model 85 only)- the stainless steel atmospheric burner

including ignition electrodes and flame detector(in model 85 there are two burners installed inopposite positions)

1.5 PACKAGE CONTENTS

The air heater is shipped with cardboard packingand internal protective pieces in pre-formedcardboard. There is an envelope inside theservice door of the appliance containing: thistechnical information manual, the warranty andservice documents, what is needed to changethe type of gas, along with the relative adhesivelabel and plug for the combustion product intakehole.

1.6 ACCESSORIES SUPPLIED ON REQUEST

In addition to the material described above, thefollowing accessories can also be supplied onrequest:

- remote-control panel, including the principaloperating commands and signals

- support brackets designed to attach theappliance in a hanging position, for air heaterversions with axial (MEC) and centrifugal (MECC) fans

- combustion product exhaust kit for horizontalwall-mounted exhaust layouts including: rigidduct, length 1 metre, joints and wind protectionterminal (duct diameter 80 mm up to modelMEC / MEC C 35, 100 mm for models MEC /MEC C from 50 to 85)

- rigid pipes, 45° and 90° bends, 90° bend withcondensate drain, connectors and windprotection terminals to create different exhaustconfigurations, including the vertical roof layout

- kit to supply combustion air from outdoorswith protection terminal

- additional air delivery grille with adjustablevertical louvers (MEC)

- drilled polyethylene pipe Ø 400 mm for airdistribution in agricultural and zoo-technicalapplications

- circular connectors for air delivery inpolyethylene duct

- air intake connector duct (MEC C)

1.7 FIELDS OF USE

MEC and MEC C air heaters can be used to buildmodular plants, consisting of one or moreappliances, to meet the heating requirements ofsmall spaces such as artisan laboratories, etc.,up to large volumes, such as industrial sheds,warehouses, churches and sports facilities.

Therefore, the heat dispersion of the buildingmust be calculated as well as the required heatingpower, selecting the number and type of airheaters in relation to the values, such as: air flowand throw, head available when using distributionducts, effective coverage of the areas to beheated, any air changes, etc.

The MEC and MEC C air heaters are built forinstallation in rooms, whether they are speciallydesigned for the appliances (technical room) orother activities (i.e. directly inside the environmentto be heated). The quality and the dimensions ofthe materials used have been chosen toguarantee a reasonable service life and aresuitable to operate the appliances, both in theirentirety and relative to their parts, provided thatthe appliances are professionally installed andare subjected to mechanical, chemical andthermal stress conditions corresponding tonormal use.

The air heater must not be installed underconditions for which it was not specificallydesigned, e.g. where the atmosphere is highlycorrosive or salty.

For “open” outdoor installations, it isnecessary to use the MEC EX series airheaters, which go beyond the scope of thismanual and which have been specificallydesigned and built for this purpose.

Based on what is prescribed by the currentinstallation standards, the MEC and MEC C airheater applications may be summarised asfollows:

- MEC series air heaters with axial, free-deliveryfans can be used if there are no special airdistribution problems or there are no physicalobstacles to obstruct such distribution, suchas partitions, shelving or bulky machinery, etc.In these cases, the effective coverage of theareas to be heated must be evaluated in relationto the air throw of the appliances

- MEC C air heaters with ductable centrifugalfans can be used for the cases in which, unlikewhat was described in the previous paragraph,it is not possible to serve the desired area

efficiently with the free air delivery. The MEC Cair heaters are also suitable if a filter must beapplied to the air intake (in fact, centrifugalfans are needed due to the load losses inducedby that filter) and/or a change is required withoutdoor air, to be conveyed by ducts.

WARNING! It is important to verify that thedesign and installation conform with currentstandards. Ensure that the environment inwhich the air heater will be installed will notcreate a hazard, i.e. where excessive (volati-le) dust, flammable or corrosive substancesand/or vapours and combustible materialsmay be present.

A B C D E F G H I L M

695 415 840 477 470 400 120 695 93 528 113

N O P Q R S T U Air Flue gas Gas

283 440 35 62 48 315 76 398 Ø140 Ø 80 1/2"

1.8 DIMENSIONS - MEC series with axial fans - Models 25 - 30 - 35

Fig. 1

Air inlet

Exhaust outlet

Gas inlet

AB

CD

EF

GH

IL

M

1.14

741

584

047

792

240

011

368

493

528

113

NO

PQ

RS

TU

Air

Flue

gas

Gas

290

440

3562

4831

581

840

Ø14

0Ø

100

1/2"

Fig.

2

1.8

DIM

EN

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50 -

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Gas

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CD

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1.7

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358

400

1.13

371

587

413

311

3

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Air

Flue

gas

Gas

353

515

3562

4831

542

490

0 Ø

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1.8

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A B C D E F G H I L M

695 415 840 797 470 400 120 695 93 528 113

N O P Q R S T U Air Flue gas Gas

283 440 35 382 48 315 76 398 Ø140 Ø 80 1/2"

1.9 DIMENSIONS - MEC C series with centrifugal fans - Models 25 - 30 - 35

Fig. 4

Exhaust outlet

Air inlet

Gas inlet

AB

CD

EF

GH

IL

M

1.1

4741

584

079

792

240

011

368

493

528

113

NO

PQ

RS

TU

Air

Flue

gas

Gas

290

440

3538

248

315

8184

0 Ø

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Ø 1

001/

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g. 5

1.9

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M

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087

086

21.

358

400

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371

587

413

311

3

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PQ

RS

TU

Air

Flue

gas

Gas

353

515

3538

248

315

424

900

Ø14

0Ø

100

1/2"

Fig.

6

1.9

DIM

EN

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Fig.

7

1.10

EX

PLO

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IEW

- M

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els

25 -

30

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1.10

EX

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- M

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els

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57

Fig.

8

1.10

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5

Fig.

9

Parts legend

1 Atmospheric burner2 Burner insulating gasket3 Gas injectors4 Ignition electrode5 Flame detection electrode6 Second ignition transformer (model 85)7 Complete gas unit8 “T” gas fitting (model 85)9 Gas supply pipe for 2nd burner (model 85)

10 Control device11 Printed circuit board12 Radio interference filter13 Cable gland14 Reset button15 Differential pressure switch16 Silicon pressure switch tube17 Safety limit thermostat18 Limit thermostat support19 Fan control thermostat20 Fan control thermostat protection21 Flue exhaust fan22 Flue exhaust diaphragm (models 25-30-35-50-57)23 Flue exhaust stainless steel duct24 Axial fan (MEC)25 Axial fan protection grille26 Fan condenser27 Flue exhaust condenser28 Centrifugal fan (MEC C)29 Centrifugal fan protection grille30 Remote-control panel (supplied on request)31 Combustion chamber/exchanger32 Flue gas mixers33 Flue gas deflector34 Exchanger cover35 Combustion air deflector (models 50-57-85)36 Burner air header (model 85)37 Front panel with delivery grille (MEC)38 Rear panel with delivery outlet (MEC C)39 Top panel40 Bottom panel41 Side panel (models 25-30-35-50-57)42 Rear panel (MEC)43 Rear panel (MEC C)44 Side box45 Service door46 Lock

Fig. 10

1.11 WIRING DIAGRAM

Ac = Control equipmentBr1 = BurnerBr2 = Second burner (MEC 85)C1 = Fan motor condenserC2 = Flue exhaust motor condenser (MEC 85)Cs = Printed circuit boardEa1 = Ignition electrodeEa2 = Br2 ignition electrode (MEC 85)Ef1 = Flue exhaust motor (MEC 25-57)Ef2 = Flue exhaust motor (MEC 85)Er = Flame detection electrodeEv = Gas solenoid valveFr = Radio interference filterM1 = Ef2 connection terminal boards (MEC 85)Mvc1 = Centrifugal fan motor (MEC C 25-85)Mvc2 = Centrifugal fan motor (MEC C 50-85)Mvc3 = Centrifugal fan motor (MEC C 85)Mve1 = Axial fan motor (MEC 25-85)Mve2 = Axial fan motor (MEC 50-85)Mve3 = Axial fan motor (MEC 85)

Op = Jumper for auxiliariesP = Differential pressure switchR1 = Fan relay (MEC C)R2-R3 = Fan relay (MEC C / MEC 85)Rs = Reset buttonSb = Lockout signalTr = Br2 ignition transformer (MEC 85)Ts1 = Safety thermostatTs2 = Second safety thermostat (MEC 85)Tv = Fan thermostat

= Fuse- - - - - = Connection to be made

= Series connection= Varying connection (model depending)

Warning:- Install an omnipolar switch with a contact opening of at

least 3 mm.- The 230 V ~ 50 Hz single-phase power supply must be

connected according to the phase-neutral polarity.

Cable colors

[b] = blue[m] = brown[n] = black

J 15

J 14

J 13

J 12

J 11

J 10 J 9 J 8 J 7 J 6 J 5 J 4 J 3 J 2 J 1

J 25

J 26

J 27

J 28

J 29

J 30

J 31

J 32

J 33

J 34

J 35

J 36

NL

J 23

J 24

Ef2

C2M1

[b]

[n]

[m]

123

1a NJ1 J2 J3 J4

N 1a N 1a

P Ef1NONC

C

Ts1

Ts2

Tr

Br2

Ea2

Br1

Ea1 Er

Ev

Ac

K3 K1 K2

Tv

L

N

SB

RS

J 22

J 21

J 20

J 19

J 18

C1

R1 R2

J 17

J 16

R3

[b ] common

[m] condenser

[n 2] max.

[n 1] min.

Mvc1

3(U)

1(U)

(4 )

(2 )

FrNL

230 V ~50 Hz

[b ] common

[m] condenser

[n 2] max.

[n 1] min.

Mvc2

[b ] common

[m] condenser

[n 2] max.

[n 1] min.

Mvc3

Op Sb Rs

Cs

3

12

[n] common

[m] condenser

[b] max. Mve1

[n ] common

[m] condenser

[b] max. Mve2

[n ] common

[m] condenser

[b] max. Mve3

L N SB RS

L N 1a N

1.12 TECHNICAL DATA TABLE Units 25 30 35 50 57 85

Heat input (Hi) kW 25,0 30,0 34,8 50,0 57,0 85,0

kcal/h 21.500 25.800 29.900 43.000 49.000 73.100

Heat output (Hi) kW 22,9 27,5 31,9 45,3 51,6 75,6

kcal/h 19.700 23.650 27.400 38.960 44.380 65.050

Gas Natural gas G20 m3/h 2,65 3,17 3,70 5,29 6,03 9,00

consumption Butane G30 kg/h 1,97 2,37 2,76 3,94 4,49 6,70

(15 °C - 1.013 mbar) Propane G31 kg/h 1,94 2,32 2,71 3,88 4,42 6,60

Burner G20 p 20 mbar mbar 10,0 10,5 12,0 10,4 10,5 11,0

pressure G30 p 28-30 mbar mbar 27,7 27,6 27,4 24,2 24,2 25,0

(15 °C - 1.013 mbar) G31 p 37 mbar mbar 36,5 36,3 36,0 32,5 32,5 32,5

Injector size G20 mm/100 310 340 350 350 370 400

G30 - G31 mm/100 175 195 210 185/240 220 240

Gas service connection “ G 1/2

Air supply diameter mm 140

Flue exhaust diameter mm 80 100

Electrical supply 230 V ~ / 1 / 50 Hz

Air volume m3/h 2.100 2.300 2.500 4.600 5.000 7.400

Fan speed (rpm) n° 1.095 1.215 1.370 1.260 1.350 1.335

MEC series Throw m 16 18 22 18 22 22

with axial fans Temperature rise °C 33 35 37 30 31 30

Sound level (at 5 m) dBA 45 47,5 50,5 50,5 54 55,5

Electric power W 175 185 215 380 400 530

Fuse A 4

Net weight kg 64 106 180

Air volume m3/h 2.000 2.150 2.500 4.300 5.000 7.300

Fan speed (rpm) n° 880 900 930 900 930 950

MEC C series Useful pressure Pa 100 100 80 100 80 80

with ductable Temperature rise °C 34 38 37 31 31 31

centrifugal Sound level (at 5 m) dBA 45 45 48,5 48 51,5 53

fans Electric power W 580 580 580 1.050 1.050 1.550

Fuse A 6,3 10 15

Net weight kg 73 125 207

2. CONTROL AND SAFETY DEVICES2.1 CONTROL DEVICE

This device is housed in a heat-resistant andshockproof plastic enclosure and is mounted onthe air heater electric board, inside the servicedoor (fig. 11).The control device operates on the ionisationflame detection principle, using a special probeon the burner.

The detection circuit must be fed with single-phase 230 V ~ mains voltage. The circuit issensitive to the phase-neutral polarity and ifthis is reversed, the device will lock outwithin the safety time, even if the flame hasa regular shape (for special cases consultour Technical Office).

2.2 GAS UNIT

The gas unit includes two, direct operationsolenoid valves with class B closing devices(maximum pressure 60 mbar) and a pressureregulator. The die-cast aluminium casing isequipped with 1/2 RP threaded gas inlet andoutlet connections and two inlet and outletpressure measurement fittings. The gas unit isalso equipped with an inlet filter (figures 12-13).

2.3 DIFFERENTIAL PRESSURE SWITCH

This device shuts off the burner if the flue gasexhaust fan flow rate is insufficient, caused byfan malfunction or an obstruction in thecombustion circuit.

Fig. 11

CONTROL DEVICE

Fig. 12

GAS UNIT - Models 25 - 30 - 35

Outlet pressure fitting

Inlet pressure fittingElectric connection

Pressure set screw

Gas

GAS UNIT- Models 50 - 57 - 85

Fig. 13

Inlet pressure fitting

Outlet pressure fitting

Pressure set screw

Gas

Electric connection

Fig. 14

DIFFERENTIAL PRESSURE SWITCH

Sealed set screw

The pressure switch is mounted on the air heaterelectric board and is connected by a silicon tubeto a pressure fitting on the exchanger to detectthe differential pressure on the combustion circuit.A set screw, located on the front of the device, isused for calibration, which is performed in thefactory, according to the appliance model, andlocked with a seal (fig. 14).

2.4 FAN THERMOSTAT

This thermostat controls fan operation, makingit start when the exchanger has reached therated operating temperature and stopping itwhen the exchanger has adequately cooled.The thermostat is attached to a threaded support,located on an element of the exchanger ( fig. 15).

2.5 SAFETY THERMOSTAT

The thermostat is designed to interrupt burneroperation when the air temperature in the airheater reaches a set value, i.e. when theexchanger overheats due to insufficient air flowor a fan malfunction. The thermostat enclosureis attached to the electric board inside the airheater service door. The sensitive bulb,connected to the thermostat enclosure by acapillary tube, is located in front of the exchanger,on a special support bracket (fig. 16).

Fig. 15

FAN THERMOSTAT

Threaded attachment

Electric connection

Fig. 16

SAFETY THERMOSTAT

Electric connection

Bulb sensor

Thermostat enclosure

SECTION 2 - TECHNICAL INFORMATION FOR THE INSTALLER

3. PRECAUTIONS3.1 GAS SAFETY (Installation and Use)

(Amendment) REGULATIONS 1990

The law requires all gas appliances to beinstalled by competent persons inaccordance with the above regulations.Failure to install appliances correctly maylead to persecution. It is in your own interestsand that of safety to ensure compliance withthe law.

3.2 RELATED DOCUMENTS

Air heater(s) must be installed in accordancewith the requirements and recommendations ofBritish Standard BS 6230 1991 “Installation ofGas Fired Forced Convection Air Heaters forCommercial and Industrial Space Heating”.

The installation must also be in accordance withthe relevant requirements of “The Gas Safety(Installation and Use regulation) and(Amendment Regulations 1990)” and the“Building” and “IEE Regulations”. Therequirements of the “Local Building StandardsOffice”, the premises “Insurance” company andthe “Fire Office” must also be observed.

3.3 TRANSPORT AND HANDLING

The MEC air heaters are supplied with cardboardpacking and internal protective pieces in pre-formed cardboard, while the MEC C seriesmodels are also supplied with wooden pallets,attached to the base of the appliance with 4screws (M8). Cap cardboard packing is attachedwith plastic straps.

The air heater can be handled with a fork-lifttruck or transpallet, making sure to balanceits weight on the supports. For safety reasons,considering the relatively heavy weight, donot try to lift the appliance by hand. Do nothang with slings or ropes, since there are nospecific anchor points. Always observe theinstructions reported on the box indicatedby the special graphic symbols.

When delivered, check that no visible damageon the packing and/or on the device has occurredduring transport. If damage is noted, immediatelysubmit a claim to the shipping agent.

3.4 DATA CHECK

Check that the air heater and its technicalcharacteristics match what is indicated by thedesign or other documents.

The type of gas for which the air heater hasbeen designed and the relative supplypressure are found on the exterior of thepacking and on a special label located on theinside of the appliance service door.

WARNING! If the type gas for which theappliance has been designed is differentfrom the one being used, the adaptationoperation must be carried out by skilledtechnical personnel, during the first start-upoperation and relative tests.

3.5 USING THE INSTRUCTIONS

WARNING! When installing or working onthe appliance, comply with all the instructionsreported in this manual. Changes to any typeof connection and non-compliance with theseinstructions will immediately invalidate thewarranty and release the manufacturer fromall responsibilities.

4. INSTALLATION4.1 LOCATION

The installation of a warm air heating systemmust be in strict accordance with any fireregulations or insurance company’srequirements pertaining to the area in whichthe system is installed, particularly wherespecial risks are involved, such as areaswhere petrol vehicles are housed, wherecellulose is sprayed, in wood-workingdepartments, etc.

In addition, where a warm air heating systemis installed in a shop or department store oran office building, any relevantrecommendations of CP3:Ch-IV pertainingto such buildings, with respect to theinstallation and maintenance of any fireescape routes, must be complied with.

As already described, the possible air heaterinstallations can be summarised into two differentsolutions:

4.1.1 Installation of MEC air heaters for thefree delivery of warm air

To ensure the optimal configuration of the airheaters within an environment, it is recommendedto observe the following instructions:

a) position the air heater as close as possible tothe occupied area, also for what concerns theinstallation height of the appliance, withouthowever taking the risk of striking peopledirectly with the flow of warm air

b)when installing the appliance consider thepresence of obstacles, such as pilasters,shelving and stored materials which mightprevent the warm air from being delivered

c) when more than one air heater is installed inthe same room, it is recommended to distributethe warm air in opposing directions (fig. 17)

d)Where there is a large inflow of cold air, suchas next to entrance doors, it is recommendedto install an air heater so that the stream ofwarm air flows directly towards the coldsources.

4.1.2 Installation of MEC C air heaters fordistribution of ducted air

For ducted installation it is recommended toobserve the following instructions:

a) for ducted units, all delivery and return airducts, including air filters, jointing and anyinsulation or lining, must be constructed entirelyof materials which will not contribute to a fire,are of adequate strength and dimensionallystable for the maximum internal and externaltemperatures to which they will be exposedduring commissioning and normal operation.

When selecting materials, it is also necessaryto consider the working environment and theair temperatures which will result when theoverheat limit thermostat is beingcommissioned. Where inter-joist spaces areused as duct routes, they should be suitablylined with a fire-resisting material

b)a full and unobstructed return air path to the airheater(s) must be provided.

If the air heater(s) will be installed in a plantroom, the return air and warm air dischargelayouts must prevent any interference withflue operation by the air circulation fan. Thereturn air intake(s) and the warm air outlet(s)should, therefore, be fully ducted, in the plantroom, to and from the air heater(s) respectively.The openings in the plant room structurecrossed by ducting must be fire stopped.

c) make sure that return-air intakes are keptclear of any sources of smells and fumes, andin special circumstances, where there is anypossibility of polluting the air with dust,shavings, etc., precautions must be taken bycarefully positioning return-air intakes andinstalling screens to prevent contamination.

4.2 MINIMUM HEIGHTS AND DISTANCES

If the appliance is installed in the room to beheated, the installation height has a direct effecton the optimum distribution of the warm air. Forthis reason the air heater should be installed withits base at a height of 2.5 metres from the ground(fig. 18).

Do not install the air heater at higher levels fromthe ground, thus limiting the stratification of theair. If this is not possible or for the case involving

Fig. 17

POSITION INDICATIONS

maintenance, there must be free access tothe front of the exchanger which containsthe fan and safety control thermostats.

4.3 AIR INTAKE AND FLUE EXHAUST DUCTS

4.3.1 Type definition

As already mentioned in point 1.1, the MEC andMEC C air heaters can be installed with differentconfigurations of the air intake and combustionproduct exhaust ducts and these differentsolutions constitute the definition of “type”.

The possible solutions are reported below inrelation to the CE certification for the appliances:

- Type C12

The combustion circuit is hermetically sealedwith respect to the environment in which the airheater is installed. The ducts pass directlythrough the outside wall of the room, withterminals close to each other (fig. 19).

- Type C52

The combustion circuit is hermetically sealedwith respect to the environment in which the airheater is installed.

Both types of ducts are connected to the outdoors,but their terminals may also be located on wallsnot in the room. The combustion products canbe exhausted also with a special duct on the roofof the building (fig. 20).

WARNING! In the previous solutions (TypeC), the intake and exhaust ducts, includingthe relative terminals, are considered by thestandards to be integral parts of the air heater.

rooms with heights greater than 6-7 metres, it isrecommended to combine the air heaters withthe installation of Arianne air mixers (see thespecific documentation), to optimise thedistribution of the air, ensuring the uniformity ofthe temperature in the environment and ensuringsignificant energy savings.

The appliance rests on two support brackets(supplied on request in two separate versions forthe MEC and MEC C series) each equipped withtwo attachment holes with a diameter of 14 mm.

WARNING! Make sure that the supportcapacity of the wall where the brackets areattached and the wall anchor system areadequate for the weight of the appliance tobe installed (see the technical data table onpage 18).

If the support brackets are built differently, attachthe appliance as required respecting the properdistance from the wall. This distance, measuredfrom the rear corner of the air heater housing,must be at least 30 centimetres for the MECseries and 40 centimetres for the MEC C series,to ensure a correct air intake to the fan(s). Forthis reason and to make maintenance easier,the air heater must not be installed inside nichesor in positions where they are difficult to access.It is recommended to respect the minimumdistances indicated in fig. 18.

Any combustible materials stored near the airheater must be at least 1.5 metres away from theappliance.

When installing MEC C ducted air heaters, itshould be recalled that, to perform

MINIMUM DISTANCES

Fig. 18

2,5

m

2,5

m

50 cm 80 cm50

cm

50 cm

80 cm 80 cm

1,5

m

30 / 40 cm

Fig. 19

Fig. 20

Top view Side view

Top viewTerminals far apart andlocated on different walls

Type C52

The combustion circuit ishermetically sealed withrespect to the environment.Both types of ducts areconnected to the outdoors,but their terminals may alsobe located on walls not inthe room.

Type C12

The combustion circuit ishermetically sealed withrespect to the environment.The ducts pass directlythrough the outside wall ofthe room, with terminalsclose to each other.

Fig. 21

Side viewExhaust directly throughthe external wall

Side viewVertical exhaust abovethe roof of the building

Type B22

Open combustion circuitwith combustion air takenfrom within theenvironment. In this casethe correct amount ofcombustion air must beguaranteed by means ofsuitable opening in thewalls.

Minimum20 cm

8 cm

Side viewWall exhaust and dischargeabove the roof of the building

Therefore, they must be requested from AC-CORRONI S.r.l., together with the appliance.

- Type B22

The combustion circuit is not hermetically sealedwith respect to the environment in which the airheater is installed. Combustion air intake isperformed within the environment, while thecombustion products are exhausted through ahorizontal duct that passes directly through anexternal wall or vertically above the roof of thebuilding (fig. 21).

If the ducts and terminals supplied by AC-CORRONI S.r.l. are not used, the followingmust be taken into consideration:

- it is recommended to use ducts with a smoothinterior surface, the diameter of which shouldnot be less than the exhaust fitting on theappliance

- the duct and terminal material must be suitablefor the specific use, in relation to the heat andchemical stress exerted by the combustionproducts

- the joints must guarantee an efficient seal andthe attachment of various elements must bestable over time

- if a vertical duct is used, it is recommended todrain off any condensate in the lower part. Ifthe vertical duct runs outside the building, it isrecommended to use insulated pipes

WARNING! In this solution (Type B22

), theroom must be adequately ventilated to ensurethe correct amount of combustion air, bymeans of openings on the sides of the room,with the dimensions and characteristicsestablished by the current safety standards.

In all the cases outlined above the length of theducts must always respect the limits describedin the next point.

4.3.2 Duct length limits

The length of the ducts must remain with thelimits described below, otherwise the load lossesgenerated might not allow the appliance to ope-rate correctly, thus causing the differentialpressure switch to be activated. It should berecalled that a bend is equivalent to a straightsegment of about 50 cm. The relative position ofthe external terminals must comply in generalwith what is indicated in figures 19-20-21 and inparticular with the specific instructions includedin the duct kit supplied on request.

Length (cm) Min. Max.

Exhaust only(Type B

22) 50 450

Exhaust + intake(Types C

12 - C

52) 2 x 50 2 x 300

4.4 INSTALLATION OPERATIONS

Based on the installation design, set up the gas(the diameters of which must ensure thenecessary gas volume) and electricity supplylines, in addition to the support brackets and theholes to pass the combustion air and flue exhaustducts.

4.4.1 Attaching the brackets

Remove the 4 screws (M8 x 30) on the bottom ofthe air heater; lift it using a suitable device andplace it on the support brackets. Adjust theposition and attach the appliance using thescrews that were previously removed.

4.4.2 Connecting the intake and exhaust ducts

Connect the ducts (according to the differentcases described in point 4.3.1) to the attachmentson the air heater and make sure they are properlysealed by using the special fittings.

WARNING! The material comprising theexternal wall crossed by the ducts and anycovering must not be sensitive to the heatproduced by the flue duct. If not, the passagehole must be protected with insulation thatinsulates the wall or the covering.The flue should terminate in a freely exposedposition and must be situated so as to preventthe combustion products from entering anyopening in a building in such a concentrationthat may be considered a health risk orbecome a nuisance.

4.4.3 Gas connection

Connect the gas supply line to the threadedfitting on the air heater by using a removablerigid connector.

It is recommended to mount a manual gas on-offvalve along the piping in an easy-to-accessposition.

Check the seal of the gas piping and make surethat it is installed in conformity with the currentstandards regarding gas plants.

4.4.4 Electrical connections

Ensure that the electric power supply available is230 V single-phase 50 Hz. Install an omnipolar

circuit-breaker with an adequate rating (with acontact opening of at least 3 mm) near theappliance to be used as a general switch to turnoff the appliance.

Insert the power supply cable through the specialcable gland, making sure to cut the wires so thatthe yellow/green earth cable is longer than theother two. This precaution, in case of accidentaldetachment , allows the earth cable to be the lastconnection to be removed. The power supplycable shall have a cross-section of 3 x 1.5 mm²,with an external diameter of 9.8 mm.

Connect the power supply cables to the phase(L) and neutral (N) attachments of the networkfilter (FR) and to the special air heater earthtower (see wiring diagrams). When connectingthe phase and neutral wires, use the faston typeterminals 6.3 x 0.8 mm supplied with theappliance.

Comply with the phase/neutral polarity,otherwise the control equipment will gene-rate a safety lock out.

THESE APPLIANCES MUST BE EARTHED.

4.4.5 Using the remote-control panel(supplied on request)

The remote-control panel (fig. 23) includes themain appliance control functions (on-off switch,electronic room thermostat, lock out andoperating signals, reset button, summerventilation). It is supplied in a kit, including anappliance connection cable, anchor bolts withscrews for wall mounting and the necessaryinstructions. The connection, already availableon the appliance board, must be performed by aqualified electrician.

WARNING! If the panel is attached to a metalstructure, such a structure must be earthed.

4.4.6 Using the room thermostat, timedthermostat or timer (not supplied)

A bridge has been installed in the applianceelectric board for external OP controls - seewiring diagrams - between the faston connectors(type 4.8 x 0.8 mm) J14 and J15. Remove thebridge and connect the above-mentionedattachments to the terminals of the regulationdevice switch. It is recommended to use a double-insulated cable for which the external diameterensures the seal of the cable gland entering theappliance.

When using a thermostat or timed thermostat, itmust be installed in a position that is easy toaccess and avoids exposure to air flows, heat

sources or excessive humidity, which may affectthe temperature measurements.

The regulation device must conform with thecurrent standards and must be installed incompliance with the standards.

4.4.7 Connecting more than one unit with asingle timer

To operate several appliances with just onetimer follow the diagram reported in fig. 22, usingthe same connections J14 and J15 described inthe previous point. To complete this specialconnection, use a normally open contact relaywith an adequate rating.

5. START-UPWARNING! The appliance initial start-upoperations and the relative tests must beperformed by skilled technical personnel.

5.1 TESTS

5.1.1 Before starting the air heater, make surethat all the current provisions and standardsrelative to the installation of these applianceshave been observed, especially for whatconcerns the correct positioning of thecombustion product exhaust duct and gas supplypiping.

5.1.2 Make sure that the 230 V ~ single-phase50 Hz electric power supply and the relativeearth wire are connected correctly to the airheater electric board.

5.1.3 Check that the gas injectors mounted onthe burner correspond to those indicated for thetype of gas to be used (table on page 18).

Fig. 22

1°air heater

2°air heater

n°air heater

Relay with ncontactsTimer

switch

NeutralPhase

n

2

1

n

2

1

J14J15

J14J15

J14J15

The appliance are delivered already set in thefactory to use natural gas G20, with a supplypressure of 20 mbar. Instead, if the gas fromthe third group is used (G30 - G31), first carryout the operations described in point 6.1.

5.1.4 Check that the gas on-off valves on themeter and near the air heater are open. Makesure that the air inside the gas supply piping hasbeen bled off.

5.2 IGNITION

5.2.1 Ignition procedure

(The instructions to the remote-control panelfunctions - supplied on request - refer to fig. 23).

a) Energise the appliance using the omnipolarcircuit-breaker described in point 4.4.4

- appliance equipped with a remote-controlpanel:

push the switch (A) to the top “ON” position.Turn the room thermostat dial (E) clockwiseto the highest value

- appliance with room thermostat:

set the thermostat regulation device to thehighest value

b) Check that the burner control equipment isnot in the lock out condition


this is indicated by the red light of the “reset”button (B). Press the button (D) to continuethe cycle

- appliance part of standard supply orequipped with room thermostat:

this is indicated by the red illuminated button

located at the bottom of the electric boardinside the appliance. Press the button tocontinue the cycle.

At this point the pre-ventilation phase begins,starting the flue exhaust fan which, whenoperating correctly, closes the differentialpressure switch contacts.

After completing the pre-ventilation phase, thesystem simultaneously opens the gas solenoidvalves and activates the transformer to dischargethe electrode to ignite the burner (in the models50 - 57 - 85 the gas solenoid valves opengradually and this cannot be modified).

From the moment in which the burner is ignited,the flame must be detected by the specialionisation sensor within the specific safety time,otherwise the control equipment enters the lockout mode.

This may occur in particular in a new plant dueto air in the gas piping. In this case, wait aboutone minute and reset the appliance (see point babove) to begin a new cycle. Repeat the operationunit the residual air has been bled off and theignition is regular.

The exchanger heating phase begins after theburner has been ignited. The exchanger reachesthe rated operating temperature after about threeminutes and at that point a thermostat starts thefan(s) to distribute warm air in the environment.

5.2.2 Controls

WARNING! When operations or visualinspections are performed on the air heaterwith the door(s) open, be extremely cautiousand work under safe conditions. Neverexpose parts of the body (hands, face, etc.),especially to the effect of any burner ignitionwhich may occur under conditions thatcannot be completely predicted or controlled.

Insert the manometer into the pressure inlet onthe burner (figures 24-25-26) after backing offthe fastening screw a few turns. Start the airheater and check that the pressure to the burnercorresponds to what is indicated in the technicaldata table.

If the pressure of the gas delivered to the burnerdoes not correspond to the value indicated, usethe special pressure set screw (figures 12-13),after having removed the protection plug, toobtain the specific value. Turn it counter-clockwise to decrease the pressure and clockwiseto increase the pressure.Fig. 23

REMOTE-CONTROL PANEL

D E

A CB

Remove the manometer and tighten the pressureset screw, carefully checking the seal. Replacethe regulator protection plug.

Turn the room thermostat dial to the minimumvalue and check that the burner shuts off.

WARNING! When the burner turns off, thefan(s) will continue to operate for a fewminutes, to properly cool the exchanger.Therefore, it is important not to turn off theair heater using the mains switch, that alsocuts off the power supply to the fan(s), sincethis might lead to overheating and trip thesafety thermostat.

Then repeat the start-up operation to observeand check that the burner has ignited correctlyand that the flame is stable. It is also necessaryto check the ignition of the second burner (model85 only), which ignites at the same time as thefirst one. The discharge of the ignition electrodein the second burner will continue for about 30seconds; check that it operates correctly.

If the remote-control panel is installed, performthe following test: while the air heater is notoperating, set the switch (A) to the bottom“ventilation” position and check that causes thefan(s) to start operating (summer ventilation).

If the MEC C series air heaters are installed withwarm air distribution ducts, operate the appliancefor at least 30 minutes. In the meantime, checkthat warm air flows freely from the duct grilles oroutlets, under the foreseen design conditions.Any obstructions, improper adjustments of theoutlets or incorrect dimensioning of the ductsmight cause the appliance to overheat, and tripthe safety thermostat. If this occurs, try to identifyand eliminate the possible causes of suchoverheating.

Once the tests have been completed, close theair heater service door(s) correctly.

5.3 USEFUL INFORMATION

It is recommended to inform the user aboutall the operations necessary to use the airheater correctly, with particular reference tothe ignition and shutdown phases and aboutthe importance of periodic tests, which mustbe performed at least once every year byskilled personnel.

6. GAS TYPE CHANGEWARNING! The operations described belowmust be carried out by skilled technicalpersonnel.

6.1 SWITCHING FROM GAS IN THE SECONDGROUP (G20) TO GAS IN THE THIRDGROUP (G30 - G31)

a) check that the envelope supplied with the airheater contains the replacement injectors, withthe relative aluminium seal washers and theadhesive label, on which to indicate the newtype of gas being used, to replace the originalone, inside the air heater service door.

- For the models 50 - 57 and 85 there is alsoan aluminium diaphragm with calibratedhole. The use of this diaphragm isdescribed in point f) below

b) check that the diameter of the injectorsindicated for the type of gas to be used (seetechnical data table on page 18) correspondsto what is stamped on the injectors

c) close the gas on-off valve and disconnect theelectric power supply

d) disassemble the injectors from the burnerusing a 12 mm hex wrench ( figures 24-25-26)

- Model 85 is equipped with two burners,mounted in an opposing positions (seeexploded diagrams). To access the secondburner it is necessary to open the servicedoor on the left of the appliance. Theoperations to replace the injectors of theaforementioned burner are similar to thosefor the other models (fig. 27).

Fig. 24

GAS INJECTOR REPLACEMENT (models 25-30-35)

Injectors

Unscrew using a 12mm hex wrench

Gas unit

Burner

Pressure inlet

e) screw the new injectors into place, insertingthe new aluminium seal washers andcompletely tighten to guarantee a proper gasseal (fig. 27)

f) (only for models 50 - 57) unscrew the gasfitting on the burner, remove the aluminiumgasket and replace it with the calibrateddiaphragm. The diameter of the holecorresponds to: 7.1 mm for model 50 and 7.6mm for model 57. Make sure that thediaphragm is in the exact position and tightenthe fitting nut (fig. 25).

(only for model 85) unscrew the fitting afterthe gas unit, corresponding to the position ofthe “T” fitting. Remove the aluminium gasketand replace it with the calibrated diaphragm.The diameter of the hole corresponds to: 9.6mm. Make sure that the diaphragm is in theexact position and tighten the fitting nut (fig.26).

g) use the pressure regulator screw, after havingremoved the protection plug, tightening it(clockwise) carefully at the limit switch.Replace the protection plug

h) start the air heater according to what isindicated in point 5.2

i) Insert the manometer into the upstreampressure inlet on the burner (figures 15-16)after having removed the closing screw. Checkthat the supply pressure corresponds to whatis indicated in the technical data table. If thegas supply pressure does not correspond tothe value indicated, use the pressure reducer(second stage) installed externally to obtainthe correct value

l) remove the manometer and tighten thepressure inlet screw

m)use a special spray or electronic leak detectorto identify any leaks in the gas circuit, withparticular attention on the burner and gas unitpressure inlets.

6.2 SWITCHING FROM GAS IN THE THIRDGROUP (G30 - G31) TO GAS IN THESECOND GROUP (G20)

WARNING! For this gas type change operationa new adapter kit is required and should berequested from the authorised dealer. In fact,it is recommended not to use the injectorsand the gaskets from the original supply,since the seals might have deteriorated.

a) check that the envelope supplied with the airheater contains the replacement injectors,with the relative aluminium seal washers andthe adhesive label, on which to indicate thenew type of gas being used, to replace theoriginal one, inside the air heater servicedoor. For the models 50 - 57 - 85 there is alsoan aluminium gasket with a diameter of 24 x18 mm

b) check that the diameter of the injectorsindicated for the type of gas to be used (seetechnical data table on page 18) correspondsto what is stamped on the injectors

c) close the gas on-off valve and disconnect theelectric power supply

d) disassemble the injectors from the burnerusing a 12 mm hex wrench ( figures 24-25-26)

- Model 85 is equipped with two burners,mounted in an opposing positions (see

Fig. 25

GAS INJECTOR REPLACEMENT (models 50 - 57)


InjectorsGas unit

Burner

Al gasketPressure inlet Fig. 26

GAS INJECTOR REPLACEMENT (model 85)


Injectors

Gas unit

Al gasket

Burner

Pressure inlet

exploded diagrams). To access the secondburner it is necessary to open the servicedoor on the left of the appliance. Theoperations to replace the injectors of theaforementioned burner are similar to thosefor the other models (fig. 27)

e) screw the new injectors into place, insertingthe new aluminium seal washers andcompletely tighten to guarantee a proper gasseal (fig. 27)

f) (only for models 50 - 57) unscrew the gasfitting on the burner, remove the calibrateddiaphragm and replace it with the newaluminium gasket. Make sure that the gasketis in the exact position and tighten the fittingnut (fig. 25)

(only for model 85) unscrew the fitting afterthe gas unit, corresponding to the position ofthe “T” fitting. Remove the calibrateddiaphragm and replace it with the newaluminium gasket. Make sure that the gasketis in the exact position and tighten the fittingnut (fig. 26)

g) remove the protection plug of the pressureregulator (figures 12-13) and back off theregulator screw 3-4 turns

h) start the air heater according to what isindicated in point 5.2

i) Insert the manometer into the pressure inleton the burner (figures 24-25-26) after havingbacked off the closing screw a few turns.Check that the pressure to the burnercorresponds to what is indicated in thetechnical data table. If the pressure of the gasto the burner does not correspond to the

value indicated, use the pressure regulatorscrew (figures 12-13) to obtain the correctvalue. Turn it counterclockwise to decreasethe pressure and clockwise to increase thepressure

l) remove the manometer and tighten thepressure inlet screw. Replace the regulatorprotection plug.

m)use a special spray or electronic leak detectorto identify any leaks in the gas circuit, withparticular attention on the burner and gas unitpressure inlets.

7. OPERATING DEFECT7.1 PRELIMINARY TESTS

Before performing specific tests, make surethat:

a) the electric power supply is properly connected(with particular attention focused on the phase-neutral polarity and earth connector) and thatany external adjustment components, suchas a room thermostat or timer, operatecorrectly

b) the gas supply is correct, the gas on-off valveis open and the pressure to the burnercorresponds to what is indicated in thetechnical data table

c) the external terminals of the combustion airintake and combustion product exhaust ductsare not obstructed or that their material hasdeteriorated

d) any remote-control panel operates properly.

7.2 POSSIBLE DEFECTS

The following is a list of possible defects alongwith their probable causes. The informationindicated in italics refers to repair operations orcorrections which are the responsibility of theauthorised Technical Service Centre.

7.2.1 The appliance does not start even if theconditions described in the previouspoints are correct.

a) the flame detection circuit of the controlequipment is malfunctioning and the initialself-check does not allow the cycle to conti-nue.

- Replace the control equipment (see point8.1).

b) The flame detection electrode has an earthleakage.

- Check the correct position of the electrode.Fig. 27

GAS INJECTOR INSTALLATION

Aluminium washerInjector

Burner

The ceramic insulation material may becracked and this is difficult to determinevisually. In case of doubt, replace the electrode(see point 8.7).

c) the contacts of the differential pressure switchare stuck in the position they assume whenthe draft is correct.

- Replace the pressure switch if its microswitchdoes not reset the contacts to the regularposition (see point 8.4).

d) the flue exhaust fan motor is malfunctioningand the differential pressure switch does notissue the enabling signal to start the cycle.

- Replace the fan making sure to re-assemblethe unit as reported in figures 38-39 (seepoint 8.9).

7.2.2 The control equipment is not in a blockcondition, but the cycle remains incontinuous pre-ventilation.

a) the differential pressure switch does not issuethe enabling signal to continue the cyclebecause the flue exhaust or air supply ductsare obstructed.

- First eliminate any obstructions that may beblocking the terminals and always check theentire duct route to identify possible damageor alterations.

b) the differential pressure switch does not issuethe enabling signal to continue the cyclebecause the flue exhaust fan does not opera-te correctly and does not exert an adequatevacuum.

- Check for any friction problems regarding fanmotor rotation. Check that the fan is in thecorrect position, that nothing interferes withthe rotation and that there are no deformations.Replace the fan, if necessary, making sure tore-assemble the unit as reported in figures38-39 (see point 8.9)

c) the differential pressure switch does not issuethe enabling signal to continue the cyclebecause it is malfunctioning or its electricalconnection has been interrupted.

- Check for damage to the connection cableand the relative terminals. Do not try to adjustthe pressure switch, removing the seal.Instead, it should be replaced.

d) the differential pressure switch does not issuethe enabling signal to continue the cyclebecause the pressure inlet tube is obstructed

or the silicon connection tube is detached orbroken.

- Check that the silicon tube is properlyconnected and that there are no holes or cuts.If it is undamaged, check the steel pressureinlet tube and clear it by removing anyobstructions or deposits. To carry out thisentire operation, it will be necessary to accessthe interior of the exchanger flue gas header.

Under particular temperature and humidityconditions, condensate may form which, ifpresent inside the silicon tube, and even justa few drops, might prevent the pressureswitch from performing the measurement.

7.2.3 At the end of the pre-ventilation phase,the ignition electrode does notdischarge and the control equipmentblocks within the safety time.

a) the ignition transformer is malfunctioning.

- Replace the control equipment which containsthe transformer. Since these are electroniccomponents, it is recommended not to try toreplace just the transformer, nor to useimproper tools.

b) the ignition electrode is no longer connectedto the equipment connector.

- Restore the connection or replace theelectrode including the cable. Do not makejoints to avoid reducing the cable insulationlevel.

c) The ignition electrode is not correctlypositioned or its ceramic insulation isdamaged, with a subsequent leakage of theignition discharge.

- Replace the electrode including the cable.

7.2.4 At the end of the pre-ventilation phase,the ignition electrode discharges, butthe flame is not formed and the controlequipment blocks within the safety time.

a) No gas supply or there is air inside the piping.

- Determine why there is no gas supply firstchecking the on-off components on the feedline. Completely bleed off any residual air andrestart the appliance.

b) The gas solenoid valves do not open becausethe coils are malfunctioning or their electricalconnection has been interrupted.

- Check if the connection cable and relativeterminals have been damaged. Use a special

tool to verify that the coils have failed andreplace them, if necessary (see point 8.3).

c) The safety thermostat is malfunctioning anddoes not allow the solenoid valves to open.

- Replace the safety thermostat (see point8.6).

7.2.5 At the end of the pre-ventilation phase,the ignition electrode discharges, theflame is formed correctly, but thecontrol equipment blocks within thesafety time.

a) The phase-neutral electric power supply isnot correctly connected to the respectiveterminals, marked as “L” and “N” and reversingthe polarity may de-activate the flamedetection device.

- Check using a multimeter or phase detectorand correctly connect the cables to thecorresponding terminals.

b) The flame detection electrode is not correctlypositioned and is not in contact with theflame.

- Check if the electrode is properly connectedand if there are any deformations. Complywith what is indicated in figures 34-35-36.

c) The flame detection electrode electricconnection has been interrupted.

- Check the electrode connection to the controlequipment. If the cable or ceramic insulationis damaged, replace the electrode inaccordance with the positions indicated infigures 34-35-36.

7.2.6 The control equipment blocks duringnormal operation.

a) The gas supply was cut off and the equipment,after repeating the ignition cycle, and withoutdetecting the flame within the safety timeperiod, entered the block mode.

- Determine why the gas supply prior to the airheater was interrupted. Restart the applianceusing the Reset button on the control panel.

b) The incorrect positioning of the external intakeand exhaust terminals has caused combustionproducts to return and this prevents the flamefrom being formed and therefore from beingdetected by the electrode .

- Change the position of the external terminals,considering that the exhaust duct shouldproject about 10 cm more than the intake

duct. Check that the terminals are not installedinside niches o recesses in the walls and thatthere are no obstructions that prevent the airfrom circulating.

c) The safety thermostat cuts off the supply tothe gas solenoid valve because overheatinghas occurred due to incorrect operation or afailure of the convection fan(s).

- Check for obstructions or dust deposits onthe fan(s) and relative grille(s). Replace themalfunctioning fan, if necessary (see point8.10).

d) The safety thermostat cuts off the supply tothe gas solenoid valve because overheatinghas occurred due to incorrect operation of thefan control thermostat.

- Replace the control thermostat of the fan(s)(see point 8.5).

7.2.7 The burner stops while it is operating,even if the ambient temperature doesnot require it.

a) The room thermostat (or the remote-controlpanel) is defective or is incorrectly positionedin the room to detect the necessary tempera-ture.

- If the panel is considered to be in the correctposition and the defect continues, the panelshould be replaced. It is recommended, sincethese are electronic components, not to try toeffect repairs on the printed circuit board ofthe panel.

b) The differential pressure switch stops theburner because the flue exhaust fan volumeis incorrect, due to an obstruction in the ductsor because the ducts are too long.

- Remove any obstructions and/or check thelength of the ducts according to what isindicated in point 4.3.2.

8. REPLACING PARTSSince specific technical skills are required toreplace the parts listed below, it isrecommended to advise the user to alwayscontact skilled technical personnel. For safetyand quality reasons, it is recommended touse original spare parts when replacingcomponents.

WARNING! All the following operations mustbe carried out while the air heater is turnedoff, disconnecting the gas and electricsupplies.

8.1 CONTROL EQUIPMENT

Disconnect the cables pulling on the relativeterminals and extracting the connectors,releasing them first from the special retainer.Replace the equipment, attached using the twoself-threading screws. Insert the terminals andthe connectors into their respective housings(fig. 28).

8.2 FUSE

Using a special tool, remove the fuse on theprinted circuit board on the electric panel insidethe air heater. The new fuse must have the samecharacteristics as the original one:“instantaneous”, certified and with a ratingcorresponding to the technical data table onpage 18. Replace the fuse with the new onexerting slight pressure until it enters the housing.

8.3 GAS SOLENOID VALVES

8.3.1 Models 25 - 30 - 35

Disconnect the electric connection on the gasunit. Remove the screw that attaches the coilblock and remove it from the housing. Pull out

the coils from the metal cage and replace themwith new ones. Replace the coil block into thehousing on the gas unit, tighten the fasteningscrew and re-establish the electrical connection(fig. 29).

8.3.2 Models 50 - 57 - 85

Disconnect the electrical connection of thedefective coil. Remove the screw that attachesthe coil to the gas unit and remove it from thehousing. Insert the new coil, tighten the fasteningscrew and re-establish the electrical connection(fig. 30).

8.4 DIFFERENTIAL PRESSURE SWITCH

Disconnect the electrical connection and thesilicon tube. Loosen the fastening screws andremove the pressure switch. Mount the newpressure switch and re-establish the electrical

Fig. 28

CONTROL EQUIPMENT REPLACEMENT

Connectors and terminalsfor electrical connections

Equipment enclosure

Fig. 30

GAS UNIT COIL REPLACEMENTModels 50 - 57 - 85

Fasteningscrew

Solenoidvalve coil

Coil cage

Gas unit

Solenoidvalve coil

Fig. 29

GAS UNIT COIL REPLACEMENTModels 25 - 30 - 35

Gas unit Coil cage

Solenoid valve coils

Fastening screw

connection making sure to respect the positionof the contacts. Re-insert the silicon tube (fig.31).

WARNING! The calibration of the newdifferential pressure switch must correspondto the appliance model on which it is replaced.In fact, the pressure switches are calibratedin the factory and sealed. Do not try to performimproper adjustments tampering with theseal.

8.5 CONTROL THERMOSTAT OF THECONVECTION FAN(S)

Remove the protection grille that shields thethermostat. Disconnect the cables and unscrewthe thermostat from the threaded support. Insertthe new thermostat, screwing it all the way in byhand (do not use tools which might damage thethermostat). Make sure that the distance between

the thermostat enclosure and the threadedsupport is not greater than 3 mm, to guaranteethat the sensor remains in contact with the wallof the exchanger. Re-establish the electricalconnection and replace the protection grille (fig.32).

8.6 SAFETY LIMIT THERMOSTAT

To access the thermostat remove the four screwswhich attach the appliance electric board.Disconnect the cables and remove the two screwsthat attach the thermostat enclosure to the board.Use a pair of pliers to pull out the thermostatsensor from its support in the front of theexchanger. Pull out the sensor and the relativecapillary element. Mount the new thermostat byreversing the order of the previous operations(fig. 33).

Fig. 31

PRESSURE SWITCH REPLACEMENT

Fastening screws

Electrical connection

Silicon tube

Fig. 32

FAN THERMOSTAT REPLACEMENT

Grille attachmentscrews

Correct distance = 3 mm

Unscrew

Thermostat

Threaded supportExchanger wall

Protection grille Fig. 34

ELECTRODE POSITIONINGModels 25 - 30 - 35

Ignition electrodeDetection electrode

Correct distancebetween electrodeand burner 3 mm

Fig. 33

SAFETY THERMOSTAT REPLACEMENT

Sensor support

Thermostatenclosure

Thermostat sensor

ignition electrode, open the service door on theleft of the appliance.

8.8 SECOND BURNER IGNITIONTRANSFORMER (MODEL 85 ONLY)

Only model 85, with a second burner, has aspecial ignition transformer, located in thecompartment on the left of the appliance, whichcan be accessed by opening the relative servicedoor.

Disconnect the power supply cables and thoseto the ignition electrode from the transformer.Remove the transformer by loosening the twoself-threading fastening screws. Insert the newtransformer and re-establish the electricalconnections respecting the connections indicatedwith the special symbols (fig. 37).

8.7 ELECTRODES

Disconnect the cable connection on the controlequipment. Remove the fastening screws andremove the electrodes from the housing in theburner. Insert the new electrodes, attach thesupports and re-establish the electricalconnection. To check the position of theelectrodes on the burner, free the burner fromthe fitting with the gas unit, remove the fourfastening screws on the air heater and extract ituntil the electrodes emerge. The position of theelectrodes with respect to the burner mustcorrespond to what is indicated in the figures 34-35-36.

Only model 85 has another ignition electrode onthe second burner, with the same relative position.To access the second burner and the relative

Fig. 35

ELECTRODE POSITIONINGModels 50 - 57

Detection electrodeIgnition electrode

Correct distancebetween electrodeand burner

3 mm

Fig. 36

ELECTRODE POSITIONINGModel 85

3 mmCorrect distancebetween electrodeand burner

Ignition electrodeDetection electrode Fig. 38

FLUE EXHAUST REPLACEMENTModels 25 - 30 - 35 - 50 - 57

Diaphragm

Scroll

Motor-fan unit

Fig. 37

IGNITION TRANSFORMERModel 85 only (second burner)

Ignition electrodecable

Electricalconnections

and extract the flexible stainless steel ducts fromthe fittings. In the rear of the appliance,corresponding to the fitting with the flue exhaustduct, unscrew the four fan scroll fastening screws.Extract the unit, being careful not to damage thegasket between the fan scroll and the rear panelof the air heater.

Disassemble the flexible stainless steel ductsfrom the unit and insert them on the new fan,checking that they have not been damaged.Insert the new unit reversing the order of theprevious operations. Carefully tighten the clampson the fittings of the flexible stainless steel ductsto ensure a proper seal; re-establish the electricalconnection (fig. 39).

8.10 CONVECTION FAN

8.10.1 MEC series axial fan

Disconnect the fan electrical connection fromthe terminal strip on the printed circuit board ofthe air heater electric panel. Unscrew the fourscrews that attach the fan grille to the rear panelof the air heater. Extract the unit and release thefan from the grille, removing the four fasteningscrews.

Clean the grille, removing all dust deposits andattach the new fan, making sure to use theoriginal screws since thread depths of more than5 mm might damage the motor. Re-insert thefan-grille unit into the housing and attach it withthe screws, inserting the grommets includingspacers (fig. 40). Re-establish the electricalconnection making sure to respect the originalconnection as shown in the diagrams andattaching the cables using suitable clamps.

8.9 FLUE EXHAUST FAN

8.9.1 Models 25 - 30 - 35 - 50 - 57

Disconnect the motor electrical connection andloosen the three scroll fastening screws. Gentlyremove the motor-fan unit and, respecting theoriginal position, insert the new unit. Tighten thescrews and re-establish the electrical connection.Make sure the fan rotates correctly and withoutfriction (fig. 38).

8.9.2 Model 85

Disconnect the fan connection from the terminalstrip on the air heater electric board. Remove thetop panel of the air heater housing using asuitable tool, lifting until releasing the snapfasteners.

Loosen the duct clamps on the exchanger fittings

Fig. 39

FLUE EXHAUST REPLACEMENTModel 85

Stainlesssteel ducts

Fan

Scroll

Flue exhaustheader

Motor

Ductclamps

Fig. 40

Grommets

FAN REPLACEMENT (MEC)

Protection grille

Motor fasteningscrews

Grille fasteningscrews

Fan Fig. 41

FAN REPLACEMENT (MEC C)Screws

Grille

Fan

Fastening screwsModels 25-30-35

Fastening screws Models 50-57-85

Carefully carry out all the operations describedin chapter 5 and, in case of malfunctions, consultchapter 7 regarding operating defects.

9.2.2 Cleaning the exchanger

Disassemble the top panel and the front panelwith the air delivery grille and remove any dustdeposits on the exchanger.

Clean the limit thermostat sensor, removing anydust deposits.

If necessary, clean the rear of the exchanger,after having disassembled the fan. Remove thedust using a brush or a jet of compressed air.

Disassemble the cover at the top of the flueexhaust header, use a circular movement toremove the internal deflector and check thatthere are no carbon deposits on the visiblesurface that may obstruct the passage ofcombustion products. If necessary, also removethe mixers from the exchanger ducts andthoroughly clean all the surfaces.

Check that the fitting duct between the headerand the flue exhaust fan has not deterioratedand that there are no deposits inside. Check thatthe pressure inlet tube of the flue pressureswitch is not obstructed.

Check the condition of the electric system andcheck the efficiency of the connections.

Carefully replace the components and checkthat they operate regularly (fig. 42).

8.10.2 MEC C series centrifugal fan

Disconnect the fan electrical connection fromthe terminal strip on the printed circuit board ofthe air heater electric panel. Unscrew the fourscrews that attach the fan to the rear panel of theair heater (on the side for models 25 - 30 - 35; atthe top and bottom for models 50 -57 -85).Extract the unit and disassemble the fanprotection grilles. Clean the grilles and mountthem on the new fan. Insert, position and attachthe new unit, re-establish the electricalconnection making sure to respect the originalconnection as shown in the diagrams andattaching the cables using suitable clamps.

9. PERIODIC MAINTENANCE OPERATION9.1 USER INFORMATION

It is recommended to advise the user to carry outthe operations indicated in point 13.1 of thismanual at least once every two months.

9.2 YEARLY INSPECTION

9.2.1 Control and safety devices

WARNING! Specific technical skills arerequired to test the control and safety devicesand this is why it is important to contactskilled personnel.

Fig. 42

CLEANING THE EXCHANGER

10. HEALTH ANDSAFETY STATEMENT

10.1 GENERAL

Under the 1987 Consumer Protection Act andSection 6 of the 1974 Health and Safety at WorkAct, we hereby provide the following informationabout substances that are hazardous to health.Product range reference: MEC and MEC CSeries air heaters.

10.2 CAUTIONARY NOTE

During the first firing operation, some smokingmay occur. This is due to the burning off ofprotective/lubricating oils used when theappliance was being manufactured. Most of thiswill have been removed during the productiontesting process. It is a wise precaution to ensurethat adequate ventilation is provided during theinitial firing operation and throughout thecommissioning period. This is particular importantif the exhaust air is blown into a confined space.This smoking does not constitute a poison hazard.

10.3 MISCELLANEOUS

Small quantities of adhesives and sealants usedin the product are dried and cured and presentno known hazard.

10.4 THERMOSTAT(Thermal overheat limit control)

Material: llluminating Kerosene.Description: Sealed vial contains a small

quantity in liquid form.Recognition: Colourless liquid, paraffin oil/

petroleum hydrocarbon odour.Characteristics: Non-corrosive, flammable with

no poisonous reference-CHpoison Class 3

Precautions: Avoid handling. This productcan irritate and remove fat fromthe skin. Prolonged contactmay cause dermatitis. Avoidbreathing vapour. Avoid eyecontact. Do not ingest.

First Aid: Skin - Wash thoroughly withsoap and water.Eyes - Rinse immediately withcopious amounts of cleanwater.

lngestion: Seek medical advice.

10.5 ELECTROLYTIC CAPACITOR

Two types are used by random selection:Recognition: 1. Plastic enclosure

2. Aluminium enclosureMaterial: Contained liquid electrolyteKnown hazards: Electric shock possible if

charged.Precautions: Discharge to ground/earth.

Do not incinerate.First Aid: Treat for electric shock íf

affected.

END OF HEALTH AND SAFETY STATEMENT

SECTION 3 - USER OPERATING AND MAINTENANCEINSTRUCTIONS

11. START-UP11.1 FIRST FIRING AND TESTING

WARNING! It should be recalled that the firstfiring of the appliance and the relative testsmust be performed by skilled technicalpersonnel. Non-compliance with this proce-dure will invalidate the warranty conditionsand release the manufacturer from allresponsibilities.

11.2 TESTS

Before operating the air heater, make sure thatthe installer has correctly carried out theoperations under his competence.

11.3 IGNITION

WARNING! Any operation on the appliancenot expressly described below must beperformed by skilled personnel.

Check that the gas on-off valves on any meterand near the appliance are open.

(The instructions to the remote-control panelfunctions - supplied on request - refer to fig. 43).

a) Energise using the omnipolar circuit-breakerinstalled near the appliance


push the switch (A) to the “ON” position. Turnthe room thermostat dial (E) clockwise to thehighest value

- appliance with room thermostat:

set the thermostat regulation device to thehighest value

After this operation, the appliance starts workingand, after about three minutes from when theburner was ignited, a thermostat starts the fan(s)to distribute warm air in the environment.

If the air heater operation is controlled by theremote-control panel (fig. 43), when the roomhas reached the desired temperature, adjust theroom thermostat by slowly turning(counterclockwise) the regulation dial (E) untilthe burner turns off, indicated by the green lamp(C).

If the air heater is controlled by another type ofdevice or a room thermostat, set the requiredtemperature according to what is indicated in theinstructions provided with the regulation device.

From this point the air heater operation will becompletely automatic and will maintain thedesired temperature in the room.

Generally, the appliance blocks during a faultor operating defect. Therefore, it isrecommended to contact a Technical ServiceCentre.

If the air heater is controlled by the remote-control panel, the block condition is signalled byturning on the red lamp on the “reset” button (B).

11.4 SHUTDOWN

11.4.1 To turn off the air heater for a short periodof time, just use the room thermostat (loweringthe set temperature value or using a switch, ifpresent) or, with a remote-control panel, settingthe switch (A) to the “OFF” position, withoutmoving the temperature regulation dial.

WARNING! When the burner turns off, the fan(s)will continue to operate for a few minutes, toproperly cool the exchanger. Therefore, it isimportant not to turn off the air heater using themains switch, that also cuts off the power supplyto the fan(s), since this might lead to overheatingand trip the safety thermostat.

11.4.2 To turn off the air heater for an extendedperiod of time:

a) follow the same operations described in point11.4.1Fig. 43

REMOTE-CONTROL PANEL

D E

A CB

b) after the fan(s) have turned off, disconnectthe electric power supply at the mains switch

c) close the gas on-off valve

11.5 SUMMER VENTILATION (applianceequipped with a remote-control panel)

During the summer, the MEC air heater can beused to ventilate the environment, excluding theburner according to the following operations:

a) close the gas on-off valve

b) turn on the electric power supply using themains switch

c) set the switch (A) to the “VENTILATION”position

d) to stop the fan, set the switch (A) to the “OFF”position.

12. PLANT MAINTENANCE12.1 ROUTINE MAINTENANCE TO BE

PERFORMED BY THE USER

It is recommended to carry out the followingoperations at the beginning of each heatingseason and then at least once every monthduring operation:

WARNING! The operations described inpoints a) b) and c) below must be performedwhile the air heater is not functioning,excluding the gas and electric supplies.

a) check that the combustion product exhaustand any air intake ducts, including the externalterminals, are not obstructed or that theirmaterial has deteriorated

b) clean the external parts of the air heatersimply by using a damp cloth

c) use a brush or a jet of compressed air toremove the dust deposits on the externalsurfaces of the exchanger, on the fan intakegrille and on the safety thermostat sensor

d) make sure that the operating phases areregular, as described in point 11.3.

12.2 ANNUAL AIR HEATER INSPECTION

To reduce possible failures to a minimum and tokeep the air heater operating at peak efficiency,and therefore providing the best output andensuring the lowest operating costs, it isrecommended to perform a general inspectionof the air heater at least once a year. Morefrequent servicing may be required dependingon the environmental conditions where the airheater is installed. Regular inspections areanecessary, especially in dirty areas, to assessthe servicing frequency.

Gas-fired air heaters MEC - MEC C series - Models 25 - 30 - 35 - 50 - 57 - 85.Technical information - Code 10179525 - Dwg. 4.86.0960 - C 500 - Printed in February 1996

UNIFICARE GLI SCHEMIELETTRICI

CONTROLLAREFORMATTAZIONE

RIFARE NUMERAZIONIFIGURE E RIFERIMENTI,

OLTRE AGLI INDICI

AGGIORNARE CODICE ERIFERIMENTI

GAS-FIRED AIR HEATERS MEC - MEC C SERIES Models 25 - 30 - … · 2004. 4. 16. · GAS-FIRED AIR...

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Transcript of GAS-FIRED AIR HEATERS MEC - MEC C SERIES Models 25 - 30 - … · 2004. 4. 16. · GAS-FIRED AIR...