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MCQUAY DIGITAL SCROLL SYSTEM

Troubleshooting

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SELF DIAGNOSIS

MDS Outdoor Unit

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SELF DIAGNOSIS

MDS Outdoor UnitMDS Outdoor Unit Compressor Protection

High & low pressure switch / Sensor

Overload protection input from compressor

Monitoring Point (Temperature Sensor) Compressor Discharge Compressor Suction Ambient Temperature Coil Inlet Coil Coil Outlet Compressor

LS HS LP HPB Series Yes 150~300 No YesA Series No No Yes Yes

LS - Low Pressure SensorHS - High Pressure SensorLP - Low Pressure Switch (0.05 Mpa / 7.25psi)HP - High Pressure Switch (2.80 Mpa / 406psi)

Pressure Swtich Setting is Factory Preset, not adjustable

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7 segment display on outdoor PCB

ITEM CODE DESCRIPTION ITEM CODE DESCRIPTION1 E0 Outdoor DLT Discharge Sensor Error 13 F2 Indoor Inlet Sensor Error2 E1 Outdoor OD Ambient Sensor Error 14 F3 Indoor Midlet Sensor Error3 E2 Outdoor RTN Return Air Sensor Error 15 F4 Indoor Outlet Sensor Error4 E3 Sump Sensor Error 16 F5 Communication Error between Indoor and Wired Controller5 E4 Outdoor Inlet Sensor Error 17 F6 Wired Controller IC Error6 E5 Outdoor Midlet Sensor Error 18 F7 Wired Controller Clock Error7 E6 Outdoor Outlet Sensor Error 19 F8 Communication Error between Indoor and Outdoor8 E7 Outdoor DLT Discharge Sensor Error 20 F9 Outdoor IC Error9 E8 System Error 21 H1 Compressor High Pressure Error

10 EE Conflict of Mode Setting 22 H2 Digital Compressor Overload11 E9 Network Communication Error 23 H3 Fixed Compressor Overload12 F1 Indoor Room Sensor Error 24 L1 Compressor Low Pressure Error

SELF DIAGNOSIS

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Indicator Code

1 2 3 4 5 6 7 8LETTER A B C D E F H L

SIGN

9 10 11 12 13 14 15LETTER N O/0 P R T U Y

SIGN

7 Segment Display on outdoor PCB

SELF DIAGNOSIS

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ERROR Code

ITEM CODE DESCRIPTION ITEM CODE DESCRIPTION0 EC00 00# indoor unit Communication failure 62 ER62 Refrigerant released1 EC01 01# indoor unit Communication failure 63 ER63 Slaver outdoor unit Communication failure

2~47 … 02~47# indoor unit Communication failure 64 ER64 TH1 temperature sensor failure48 ER48 Digital compressor Overload 65 ER65 TH2 temperature sensor failure49 ER49 Fix 1 compressor Overload 66 ER66 TH3 temperature sensor failure50 ER50 Fix 2 compressor Overload 67 ER67 TH4 temperature sensor failure51 ER51 Fix 3 compressor Overload 68 ER68 TH5 temperature sensor failure52 ER52 Discharge pressure is too high 69 ER69 TH6 temperature sensor failure53 ER53 Suction pressure is too low 70 ER70 TH7 temperature sensor failure54 ER54 Outdoor unit's IC Error 71 ER71 TH8 temperature sensor failure55 ER55 System Error 72 ER72 TH9 temperature sensor failure56 ER56 Discharge temperature is too high 73 ER73 TH10 temperature sensor failure57 ER57 - 74 ER74 TH11 temperature sensor failure58 ER58 4 way valve failure 75 ER75 TH12 temperature sensor failure59 ER59 Ambient temperature is beyond the limit 76 ER76 Discharge pressure sensor failure60 ER60 Emergency Runing 77 ER77 Suction pressure sensor failure61 ER61 Subheating is beyond the limit 78 EC78 All indoor units Communication failure

LED of outdoor PCB

SELF DIAGNOSIS

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MDS Indoor UnitMDS Indoor Unit

Temperature SensorCoil InletCoilCoil OutletReturn air

SELF DIAGNOSIS

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ERROR CodeLCD Indicator of controller

ITEM CODE DESCRIPTION1 E0 System malfunction2 E1 Sensor broken (TH1 discharge temp.)3 E2 Sensor broken (TH2 inlet coil 1#)4 E3 Sensor broken (TH3 mid coil 1#)5 E4 Sensor broken (TH4 inlet coil 2#)6 E5 Sensor broken (TH5 mid coil 2#)7 E6 Sensor broken (TH6 inlet coil 3#)8 E7 Sensor broken (TH7 mid coil 3#)9 E8 Sensor broken (TH8 ambient temp)

10 E9 Sensor broken (TH9 outlet coil)11 EA Sensor broken (TH10subcool outlet)12 EB Sensor broken(TH11subcool suction)13 EC Sensor broken (TH12 suction)14 EF Emergency run15 F0 Outdoor storage malfunction16 F1 Sensor broken (indoor inlet coil) 17 F2 Sensor broken (indoor mid coil)18 F3 Sensor broken (indoor outlet coil)19 F4 Sensor broken (indoor return air )20 F5 Sensor broken (indoor supply air)21 F6 Indoor and controller communication malfunction22 F7 Ambient temp exceed the limit

ITEM CODE DESCRIPTION23 F8 4wv malfunction24 F9 Refrigerant leakage25 FA Controller storage malfunction26 FB Water pump(indoor drain pump)27 FC Indoor and outdoor communication malfunction28 FE Outdoor master and slave communication malfunction29 H0 Digital comp overload30 H1 Fixed comp1 overload31 H2 Fixed comp2 overload32 H3 Fixed comp3 overload33 H4 High pressure too high34 H5 Sensor broken, high pressure35 H6 Discharge temp too high36 L0 Super heat too low37 L1 Low pressure too low38 L2 Sensor broken, low pressure39 10 System malfunction40 11 Sensor broken(slaveTH1 discharge temp)41 12 Sensor broken(slaveTH2 inlet coil 1#)42 13 Sensor broken(slaveTH3 mid coil 1#)43 14 Sensor broken(slaveTH4 inlet coil 2#)44 15 Sensor broken(slaveTH5 mid coil 2#)

ITEM CODE DESCRIPTION45 16 Sensor broken(slaveTH6 inlet coil 3#)46 17 Sensor broken(slaveTH7 mid coil 3#)47 18 Sensor broken(slaveTH8 ambient temp)48 19 Sensor broken(slaveTH9 outlet coil)49 1A Sensor broken(slaveTH10subcool outlet)50 1B Sensor broken ( slave TH11 subcool suction)51 1C Sensor broken(slaveTH12 suction)52 1F Emergency run(slave)53 20 Outdoor storage malfunction(slave)54 27 Ambient temp exceed the limit(slave)55 28 4wv malfunction(slave)56 29 Refrigerant leakage(slave)57 30 Digital comp overload(slave)58 31 Fixed comp1overload(slave)59 32 Fixed comp2 overload(slave)60 33 Fixed comp3 overload(slave)61 34 High pressure too high(slave)62 35 Sensor broken, high pressure(slave)63 36 Discharge temp too high(slave)64 40 Super heat too low(slave)65 41 Low pressure too low(slave)66 42 Sensor broken, low pressure(slave)

SELF DIAGNOSIS

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ERROR Code

Indication light twinkle related to malfunction code :

LED Indicator of Receiver

SELF DIAGNOSIS

ITEM Type Heat Sleep/Fan Dry1 Indoor sensor error2 Indoor pump error3 Communication error4 Outdoor sensor error5 Compressor overload 6 Pressure switch trip7 Pressure sensor error8 System failure9 Others

LED ONLED OFFLED BLINK

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TROUBLESHOOTING

Frequent Malfunction for Commissioning – Communication Error

Symptom:For A series Outdoor, the 7 segment display C-For B series Outdoor, the 7 segment display EC78For Wired Handset, the LCD panel display FCFor LED Display, the Heat LED will be blinking

Potential Caused A:The communication chip MAX485 of outdoor unit is damaged (Possibility is low. The Communication is tested before ship out)Solution: To replace the MAX485 chip

Potential Caused B:The communication wires A/B get crossed each other or not connected(Most common caused)Solution: Check on all wiring. Ensure proper tighten and the polarity is consistent.

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TROUBLESHOOTING

Potential Caused C:Shielding wire is connected to ground terminal (not grounded).(Long wiring and running the communication wire together with power supply wire will cause this to happen)Solution: Ensure the shielding wire is only grounded at the outdoor unit. Do not run the communication wire with the power supply wire together.

Potential Caused D:Address of indoor are wrongly set(Caution, the indoor address must be start at ‘0000’ and follow. Do no jump the number.)Solution: Make sure the address start from ‘0000, did not skip any address and no repetition.

Frequent Malfunction for Commissioning – Communication Error (cont’)

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TROUBLESHOOTING

Symptom:For A series Outdoor, the 7 segment display CX (X – Indoor Unit Number)For B series Outdoor, the 7 segment display ECXX (XX – Indoor Unit Number)For Wired Handset, the LCD panel display FCFor LED Display, the Heat LED will be blinking

Frequent Malfunction for Commissioning – Specific Indoor Communication Error

Example:For A series Outdoor, the 7 segment display C3 (Indoor Unit Number 4 not communicating)

For B series Outdoor, the 7 segment display EC03 (Indoor Unit Number 4 not communicating)

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TROUBLESHOOTING

Potential Caused A:Indoor Unit PCB has no power supply.(Possible the power supply to the indoor had been turned off)Solution: Check the power supply of the indoor power.

Frequent Malfunction for Commissioning – Specific Indoor Communication Error (cont’)

Potential Caused B:Indoor Unit address error.(Possible the indoor address is not set or duplication)Solution: Check the indoor model address.

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TROUBLESHOOTING

Frequent Malfunction for Commissioning – Specific Indoor Communication Error (cont’)

Potential Caused D:Wrong quantity of indoor set.(Possible the quantity of indoor unit set in the outdoor PCB is not tally with the actual indoor quantity)Solution: Check the quantity of indoor unit setting at the outdoor PCB.

Potential Caused C:Indoor Unit PCB malfunction.(Possibility is low. PCB communication is tested before ship out.)Solution: Replace with another PCB and check the communication

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If the followings malfunction occurred, please follow the steps below to resolve :

TROUBLESHOOTING

Symptom Possible Caused Solution

Indoor temperature is higher (heating) or lower (cooling) than setting temperature

Change the set temperature

When heating and defrost mode, indoor unit is just running

Wait for the defrost cycle to finish

Power is not on Check and connect the powerFuse broken in main power supply Replace the fuseAir filter too dirty Clean or replace the filterReturn air barrier Remove the barrierLow battery Replace the batteryWrong installation of battery Install properly

Compressor stop and fan work normally

Units do not work

Cooling or heating not enough

Remote controller unreadable

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Thank YouThank You