Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.Catalog No. 04-56380002-01 Printed in U.S.A. Form 38AH-9W Pg 1 709 4-09 Replaces: 38AH-8W

Wiring DiagramsUnits Produced After April 20, 2009

(Includes Variable Air Volume ModuPanel™ Control)

INDEX

Fig.Unit 38AH with Two-Stage Thermostat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9One 38AH Dual-Circuit Condensing Unit with ModuPanel Control . . . . . . . . . . . . . . . . . 10Two 38AH Dual-Circuit Condensing Units with ModuPanel Control . . . . . . . . . . . . . . . . . 11

LEGEND (For Fig. 1-11)

UNIT 38AHELECTRICAL

CHARACTERISTICS(V-Ph-Hz)

DIAGRAM TYPE FIGURE NO. LABEL DIAGRAM NO.

024-034

208/230-3-60,460-3-60

Component Arrangement 1 38AH500185-4Power Schematic 2 38AH500184-5

575-3-60Component Arrangement 3 38AH500181-4

Power Schematic 4 38AH500180-5

380-3-60Component Arrangement 5 38AH500183-4

Power Schematic 6 38AH500182-5

230-3-50, 380/415-3-50346-3-50

Component Arrangement 7 38AH500187-4Power Schematic 8 38AH500186-5

38AH024-034Air-Cooled Condensing Units

50/60 Hz

AFR — Airflow RelayAFS — Airflow SwitchATS — Air Temperature SwitchC — Contactor, CompressorCB — Circuit BreakerCH — Crankcase HeaterCM — Control ModuleCOMP — CompressorCOTP — Compressor Overtemperature

ProtectionCR — Control RelayDU — DummyEQUIP — EquipmentFC — Fan ContactorFIOP — Factory-Installed OptionFM — Fan MotorFR — Fan RelayFU — FuseGND — GroundHPS — High-Pressure Switch

IFC — Indoor (Evaporator) Fan Contactor

LLSV — Liquid Line Solenoid ValveLPS — Low-Pressure SwitchMMF — Motormaster® FuseMMPT — Motormaster Pressure

TransducerMPR — ModuPanel RelayNEC — National Electrical Code

(U.S.A. Standard)OPS — Oil Pressure SwitchPL — PrimaryPRI — PrimaryRLA — Rated Load AmpsSEC — SecondaryTB — Terminal BlockTRAN — TransformerU — UnloaderVAV — Variable Air Volume

Plug

Receptacle

Terminal Block Connection

Unmarked Terminal

Marked Splice

Unmarked Splice

Factory Wiring

Field Control Wiring

Field Power Wiring

Indicates common potential. (Does not represent wiring.)

2

NOTES (For Fig. 1-8)1. For TRAN2: for 208/230 v connect to H3; for 460 v, connect to

H4.2. TRAN 1: for 208/230 v, connect to orange lead; for 460 v, con-

nect to black lead.3. Compressor and fan motors are thermally protected. Three-

phase motors are protected against primary single-phasingconditions.

4. Replacement of original wires must be with type 90 C wire or itsequivalent.

5. Factory wiring is in accordance with NEC. Field modifications oradditions must be in compliance with all applicable codes.

6. Wiring for field power supply must be rated 75 C. Use copper,copper-clad aluminum, or aluminum conductors.

7. FU1 is used on 208/230-3-60 units only.8. Thermostat wire between RC and TB2-1 is not connected when

AFS is used.9. Control circuit power (va) available at TB2 is as follows:

10. Reset OPS before resetting thermostat.11. The AFR is used only when 38AH is connected to a single air

handler. Use airflow relay Carrier part no. HN61KK040,HN61KK060, or equivalent.

12. The following table lists information for replacement of CB3,CB4, and CB5.

VA ITEM40 Standard unit, no winter start34 Standard unit with winter start on circuits no. 1 and 216 VAV VIOP, no winter start

9 VAV FIOP with winter start on circuits no. 1 and 2

CB3 CB4 AND 5Max

VoltageRating

Mfg Part No.Potter &

Brumfield

Must-Trip

Amps

MaxVoltageRating

Mfg Part No.Potter &

Brumfield

Must-Trip

Amps250-v W28X-1029-5 5.0 250-v W2BX-1024-3.2 3.2

3

NOTES (cont)13. The motor-compressor is a thermally protected system. Circuit

breaker must-trip amps are less than or equal to 156% RLA.The following tables list compressor and fan circuit breakerdata.

60 Hz UNITS

50 Hz UNITS

UNITSIZE38AH

MAINVOLTAGE

CONTROLVOLTAGE

COMP CB1 AND 2 MUST-TRIPAMPSHeinemann Airpax

024500 208/230 11524 47-100-85 209-3-2599-372 55

028500 208/230 11524 47-100-76 209-3-2599-410 61

034500 208/230 11524

CB1 47-100-76 209-3-2599-410 61CB2 47-100-82 209-3-2599-311 89

024600 460 11524 CF3-Z33-34 219-3-2600-438 27

028600 460 11524 CF3-Z33-62 219-3-2600-452 31

034600 460 11524

CF3-Z33-62 219-3-2600-452 31CF3-Z33-59 219-3-2600-464 42

024100 575 11524

CB1 CF3-Z33-61 219-3-2600-451 25CB2 CF3-Z33-61 219-3-2600-451 25

028100 575 11524

CB1 CF3-Z33-61 219-3-2600-451 25CB2 CF3-Z33-61 219-3-2600-451 25

034100 575 11524

CB1 CF3-Z33-61 219-3-2600-451 25CB2 CF3-Z229-16 219-3-2600-561 32

024200 380 23024 CF3-Z33-89 219-3-2600-459 33.6

028200 380 23024 CF3-Z228-38 219-3-2600-539 37

034200 380 23024

CF3-Z228-38 219-3-2600-539 37CF3-Z228-39 219-3-2600-540 48

UNITSIZE38AH

MAINVOLTAGE

CONTROLVOLTAGE

COMP CB1 AND 2 MUST-TRIPAMPSHeinemann Airpax

024800 230 23024 47-100-85 209-3-2599-372 55

028800 230 23024 47-100-76 209-3-2599-410 61

034800 230 23024

CB1 47-100-76 209-3-2599-410 61CB2 47-100-82 209-3-2599-311 89

024900 380/415 23024 CF3-Z33-34 219-3-2600-438 27

028900 380/415 23024 CF3-Z33-62 219-3-2600-452 31

034900 380/415 23024

CB1 CF3-Z33-62 219-3-2600-452 31CB2 CF3-Z33-59 219-3-2600-464 42

024300 346 23024 CF3-Z33-89 219-3-2600-459 33.6

028300 346 23024 CF3-Z33-38 219-3-2600-563 37

034300 346 23024

CB1 CF3-Z228-38 219-3-2600-539 37CB2 CF3-Z228-39 219-3-2600-540 20

4

OPERATING SEQUENCE

Standard Constant Volume Unit with 2-StageCooling Thermostat — Seven seconds after a thermo-stat call for the first stage of cooling, compressor no. 1 and theoutdoor fans start. The no. 2 fan only starts if the outdoor ambi-ent temperature is above 70 F (21.1 C). The oil-pressure switchand the low-pressure switch are bypassed for 1 and21/2 minutes, respectively. If either the low-pressure switch oroil pressure switch remain open after the delay, the unit shutsdown and goes into alarm mode. The indoor-fan motor startsimmediately whenever there is a call for cooling. If a liquid linesolenoid valve has been installed (for refrigerant control duringthe off cycle), then the solenoid valve for compressor no. 1opens immediately upon a call for cooling.

On standard units, compressor no. 1 operates either fullyloaded or at one step of unloading, depending on the suctionpressure, which is dependent on the evaporator load conditions.

As the cooling demand increases, the thermostat calls forthe second stage of cooling. Within 7 seconds from a call forthe second stage of cooling, compressor no. 2 starts. The oilswitch and low-pressure switch for circuit no. 2 are bypassedduring start-up.

As the cooling load is satisfied, the thermostat stops the callfor the second stage of cooling, which in turn deenergizes com-pressor no. 2, closes the no. 2 liquid line solenoid (if installed)and energizes the compressor no. 2 crankcase heater.

If the space temperature continues to decrease, then thethermostat stops the call for the first stage of cooling, whichthen deenergizes compressor no. 1 and the outdoor fans, closesthe no. 1 liquid line solenoid valve (if installed), and energizesthe compressor no. 1 crankcase heater.

The unit controls prevent both compressors from reenergiz-ing within 3 minutes from a previous call for operation.

If the unit safeties trip during operation, refer to the Installa-tion Instructions shipped with the unit. To reset the lockoutmode, cycle the unit power.NOTE: If the thermostat fan switch is in the auto position, theindoor fan cycles on and off as the thermostat calls for cooling(or heating). If the switch is in the continuous position, the fanruns when the outdoor unit is powered.

Optional Variable Air Volume Unit with Modu-Panel™ Control — The ModuPanel control regulates upto 10 stages of cooling to maintain a leaving-air temperaturefor variable air volume (VAV) applications. When connected toone 38AH condensing unit, only 6 stages are used. SeeTable 1 for unit loading and compressor operating sequence.

When the timeclock connected to the panel closes, theindoor-fan contactor is energized through a field-supplied re-lay. (The relay must be a pilot-duty SPST relay with 115-v coiland 30 va maximum coil draw.) After the time delays pro-grammed into the ModuPanel control have elapsed, and withthe leaving air above the set point, the stages of mechanicalcooling are sequenced as follows:

1. Stage 1 starts compressor no. 1 with 2 banks of cylin-ders unloaded (1/3 loaded). Both unloader solenoids areenergized.

2. Stage 2 loads one bank of compressor no. 1 cylinders(2/3 loaded) by deenergizing unloader solenoid no. 1.

3. Stage 3 loads the second bank of compressor no. 1 bydeenergizing unloader solenoid no. 2.

4. Stage 4 starts compressor no. 2 and unloads 2 banks ofcompressor no. 1 cylinders unloaded (1/3 loaded). Bothunloader solenoids are energized.

5. Stage 5 loads one bank of compressor no. 1 cylinders(2/3 loaded) by deenergizing unloader solenoid no. 1.

6. Stage 6 loads one bank of compressor no. 1 cylinders(fully loaded) by deenergizing unloader solenoid no. 2.

Two Optional Variable Air Volume Units with aSingle ModuPanel Control — The ModuPanel con-trol regulates up to 10 stages of cooling to maintain a leaving-air temperature for variable air volume (VAV) applications.When connected to two 38AH condensing units, all 10 stagesare used. See Table 2 for unit loading and compressor operat-ing sequence.

When the timeclock connected to the panel closes, theindoor-fan contactor is energized through a field-suppliedrelay. (The relay must be a pilot-duty SPST relay with 115-vcoil and 30 va maximum coil draw.) After the time delays pro-grammed into the ModuPanel control have elapsed, and withthe leaving air above the set point, the stages of mechanicalcooling are sequenced as follows:

1. Stage 1 starts unit no. 1 compressor no. 1 with 2 banksof cylinders unloaded (1/3 loaded). Both unloader sole-noids are energized.

2. Stage 2 loads one bank of unit no. 1 compressor no. 1cylinders (2/3 loaded) by deenergizing unloader solenoidno. 1.

3. Stage 3 turns off unit no. 1 compressor no. 1 and startscompressor no. 2 fully loaded.

4. Stage 4 starts unit no. 1 compressor no. 1 with 2 banks ofcylinders unloaded (1/3 loaded). Both unloader solenoidsare energized.

5. Stage 5 loads one bank of unit no. 1 compressor no. 1 cyl-inders (2/3 loaded) by deenergizing unloader solenoidno. 1.

6. Stage 6 loads one bank of unit no. 1 compressor no. 1cylinders (fully loaded) by deenergizing unloadersolenoid no. 2.

7. Stage 7 starts unit no. 2 compressor no. 1 with 2 banks ofcylinders unloaded (1/3 loaded). Both unloader solenoidsare energized.

8. Stage 8 turns off unit no. 2 compressor no. 1 and startscompressor no. 2 fully loaded.

9. Stage 9 starts unit no. 2 compressor no. 1 with 2 banks ofcylinders unloaded (1/3 loaded). Both unloader solenoidsare energized.

10. Stage 10 loads 2 banks of unit no. 2 compressor no. 1cylinders (fully loaded) by deenergizing both unloadersolenoids.

Restart — Manual reset of the 24-v control circuit isrequired if unit is shut down by any of the safety devices. Ap-plicable devices include the high-pressure switch (HPS), low-pressure switch (LPS), oil-pressure switch (OPS), and com-pressor overtemperature protection (COTP) switch. To restartthe unit after the unit has been shut down, raise the thermostatset point above the space temperature (thereby removing thecall for cooling) and then lower the set point back to the desiredsetting.

If unit circuit breakers trip during unit shutdown, they mustbe reset manually.

Causes of Complete Unit Shutdown:• interruption of supplied power• open compressor overtemperature protection (COTP)• compressor electrical overload protection (CB1 or CB2) • open high-pressure or low-pressure safety switches• open oil pressure switch

5

Table 1 — Unit Loading Sequence with ModuPanel™ Control

Table 2 — Loading Sequence, Two Condensing Units with ModuPanel Control

STAGE NO. CYLINDERSLOADED CYLINDERS

CAPACITY STEP (%)Compressor No. 1 Compressor No. 2

1 2 2 — 172 4 4 — 333 6 6 — 504 8 2 6 675 10 4 6 836 12 6 6 100

STAGE NO. CYLINDERSUNIT 1 LOADED CYLINDERS UNIT 2 LOADED CYLINDERS

CAPACITY STEP (%)CompressorNo. 1

CompressorNo. 2

CompressorNo. 1

CompressorNo. 2

1 2 2 — — — 82 4 4 — — — 173 6 — 6 — — 254 8 2 6 — — 335 10 4 6 — — 416 12 6 6 — — 507 14 6 6 2 — 588 18 6 6 — 6 759 20 6 6 2 6 83

10 24 6 6 6 6 100

6

Fig

. 1 —

Co

mp

on

ent

Arr

ang

emen

t, 3

8AH

024-

034,

208

/230

-3-6

0 an

d 4

60-3

-60

Un

its

a38-7085.eps

7

Fig. 2 — Power Schematic, 38AH024-034, 208/230-3-60 and 460-3-60 Units

a38-7086

8

Fig

. 3 —

Co

mp

on

ent

Arr

ang

emen

t, 3

8AH

024-

034,

575

-3-6

0 U

nit

s

a38-7087

9

Fig. 4 — Power Schematic, 38AH024-034, 575-3-60 Units

a38-7088

10

Fig

. 5 —

Co

mp

on

ent

Arr

ang

emen

t, 3

8AH

024-

034,

380

-3-6

0 U

nit

s

a38-7089

11

Fig. 6 — Power Schematic, 38AH024-034, 380-3-60 Units

a38-7090

12

Fig

. 7 —

Co

mp

on

ent

Arr

ang

emen

t, 3

8AH

024-

034,

230

-3-5

0, 3

80/4

15-3

-50

and

346

-3-5

0 U

nit

s

a38-7091

13

Fig. 8 — Power Schematic, 38AH024-034, 230-3-50, 380/415-3-50 and 346-3-50 Units

a38-7092

14

Fig

. 9 —

Un

it 3

8AH

wit

h T

wo

-Sta

ge

Th

erm

ost

at

*U

se th

erm

osta

t wiri

ng s

how

n he

re fo

r si

ngle

air-

hand

ler

appl

icat

ions

.†C

B3

prot

ects

con

trol

circ

uit a

t the

follo

win

g un

it vo

ltage

s:

**F

or a

sin

gle

air

hand

ler,

LLS

V v

alve

1 i

s to

be

used

on

the

low

er(n

o. 1

) ev

apor

ator

circ

uit.

The

LLS

V v

alve

2 i

s to

be

used

on

the

uppe

r (n

o. 2

) ev

apor

ator

circ

uit.

††O

nly

one

indo

or-f

an c

onta

ctor

is r

equi

red

on s

ingl

e ai

r-ha

ndle

r ap

pli-

catio

ns.

Use

Car

rier

acce

ssor

y pa

rt n

o. 4

0RR

9001

81 f

or i

ndoo

r-fa

nco

ntac

tor.

CO

NT

RO

L C

IRC

UIT

PR

OT

EC

TE

D A

T:(V

-Ph

-Hz)

UN

IT (

V-P

h-H

z)

115-

1-60

208/

230-

3-60

460-

3-60

575-

3-60

230-

1-60

380-

3-60

230-

1-50

230-

3-50

346-

3-50

400-

3-50

NO

TE

S:

1.C

B4

prot

ects

TB

2 ci

rcui

t; C

B3

prot

ects

TB

3 ci

rcui

ts.

2.LL

SV

1 an

d LL

SV

2 ar

e fie

ld s

uppl

ied.

3.O

n 20

8/23

0, 4

60,

and

575-

3-60

uni

ts,

TB

2 is

24-

van

d T

B3

is 1

15-v

. O

n 38

0-3-

60 a

nd 2

30,

346,

and

400-

3-50

uni

ts, T

B2

is 2

4-v

and

TB

3 is

230

-v.

a38-7050.eps

15

a38-7113

SEE

MO

DU

PAN

EL A

CC

ESSO

RY IN

STA

LLAT

ION

FO

R SC

HEM

ATIC

C

→ F

ig. 1

0 —

On

e 38

AH

Du

al-C

ircu

it C

on

den

sin

g U

nit

wit

h M

od

uP

anel

™ C

on

tro

l

NO

TE

S:

1.Fa

ctor

y w

irin

g is

in a

ccor

danc

e w

ith N

atio

nal E

lect

rical

Cod

e (N

EC

). F

ield

mod

ifica

tions

or

addi

tions

mus

t be

in c

ompl

i-an

ce w

ith a

ll ap

plic

able

cod

es.

2.W

irin

g fo

r fie

ld p

ower

sup

ply

mus

t be

rate

d 75

° C

min

imum

. Use

cop

per,

copp

er-c

lad

alum

inum

or

alum

inum

con

duct

ors.

Max

imum

in

com

ing

wire

si

ze

for

mai

n te

rmin

al

bloc

k (T

B1)

is

35

0 m

axim

um

kcm

il (2

30

v).

All

othe

r vo

ltage

s2/

0 m

axim

um.

3.Te

rmin

al b

lock

s T

B2

and

TB

3 ar

e fo

r ex

tern

al fi

eld

cont

rol c

onne

ctio

ns. C

ontr

ol c

onne

ctio

ns a

re to

be

Cla

ss 2

wiri

ng.

4.F

ield

sup

plie

d co

mpo

nent

s (I

FC

, LL

S-1

and

LLS

-2)

mus

t ha

ve a

max

imum

sea

led

coil

ratin

g of

30

va (

.25

amps

at

120

vac,

.13

am

ps a

t 12

0 va

c).

The

rmos

tats

mus

t ha

ve a

pilo

t du

ty r

atin

g of

120

va,

(1

amp

at 1

20 v

ac,

.52

amp

at23

0 va

c). T

he fa

n sw

itch

mus

t ha

ve a

pilo

t dut

y ra

ting

of 3

0 va

(.2

5 am

p at

120

vac

, .13

am

p at

230

vac

). T

he A

FS

mus

tha

ve a

pilo

t dut

y ra

ting

of 3

0 va

(1.

25 a

mps

at 2

4 va

c).

5.R

epla

cem

ent o

f fac

tory

wire

s m

ust b

e w

ith ty

pe 1

05°

C w

ire o

r its

equ

ival

ent.

6.F

ield

-sup

plie

d liq

uid

line

sole

noid

val

ves

inst

alle

d at

the

evap

orat

or a

re r

equi

red

on C

ircui

ts 1

and

2 o

n al

l uni

ts.

7.T

RA

N1

has

75 v

a av

aila

ble

for

field

-inst

alle

d ac

cess

orie

s.8.

Mod

uPan

el c

ontr

ol is

wire

d fo

r on

e ai

r ha

ndle

r on

ly.

709

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.Catalog No. 04-56380002-01 Printed in U.S.A. Form 38AH-9W Pg 16 709 4-09 Replaces: 38AH-8W

Copyright 2009 Carrier Corporation

Fig

. 11

— T

wo

38A

H D

ual

-Cir

cuit

Co

nd

ensi

ng

Un

its

wit

h M

od

uP

anel

™ C

on

tro

l

MP

R

SE

E M

OD

UPA

NE

L A

CC

ES

SO

RY

INS

TALL

ATIO

N F

OR

SC

HE

MAT

IC

SE

E M

OD

UPA

NE

L A

CC

ES

SO

RY

INS

TALL

ATIO

N F

OR

SC

HE

MAT

IC

MP

R

NO

TE

S:

1.Fa

ctor

y w

iring

is

in a

ccor

danc

e w

ith N

atio

nal

Ele

ctri

cal

Cod

e(N

EC

). F

ield

mod

ifica

tions

or

addi

tions

mus

t be

in c

ompl

ianc

e w

ithal

l app

licab

le c

odes

.2.

Wiri

ng f

or f

ield

pow

er s

uppl

y m

ust

be r

ated

75°

C m

inim

um.

Use

copp

er, c

oppe

r-cl

ad a

lum

inum

or

alum

inum

con

duct

ors.

Max

imum

inco

min

g w

ire s

ize

for

mai

n te

rmin

al b

lock

(T

B1)

is

350

kcm

il(2

30 v

). A

ll ot

her

volta

ges

2/0

max

imum

.3.

Term

inal

blo

cks

TB

2 an

d T

B3

are

for

exte

rnal

fiel

d co

ntro

l con

nec-

tions

. Con

trol

con

nect

ions

are

to b

e C

lass

2 w

iring

.4.

Fie

ld s

uppl

ied

com

pone

nts

conn

ecte

d to

TB

3 (e

.g.,

LLS

V1

and

LLS

V2)

can

not e

xcee

d 75

va

tota

l ind

uctiv

e lo

ad a

t 24

vac,

so

that

TR

AN

1 do

es n

ot b

ecom

e ov

erlo

aded

. T

he a

ir ha

ndle

r au

xilia

rym

otor

sta

rter

con

tact

s m

ust

have

a m

inim

um c

onta

ct r

atin

g of

30 v

a at

24

vac.

The

airf

low

sw

itch

mus

t ha

ve a

min

imum

con

tact

ratin

g of

125

va

at 2

4 va

c.5.

Rep

lace

men

t of f

acto

ry w

ires

mus

t be

with

type

105

° C

wire

or

itseq

uiva

lent

.6.

Fie

ld s

uppl

ied

liqui

d lin

e so

leno

id v

alve

s in

stal

led

at t

he e

vapo

ra-

tor

are

requ

ired

on C

ircui

ts 1

and

2 o

n al

l uni

ts.

7.T

RA

N1

has

75 v

a av

aila

ble

for

field

-inst

alle

d ac

cess

orie

s.8.

Mod

uPan

el is

wire

d fo

r on

e ai

r ha

ndle

r on

ly.

9.A

FR

onl

y us

ed w

ith s

ingl

e ai

r ha

ndle

r. U

se H

N61

KK

040,

060

oreq

uiva

lent

.10

.F

or M

PR

, use

HN

61K

K04

0,06

0 or

equ

ival

ent.