3
IOM - 7602-444 Communicating Service Tool
Comfort-Aire/Century Communicating Service Tool 7602-444 allows install and service technicians to configure and diagnose
Comfort-Aire/Century Digital Communicating Units without installing a digital communicating thermostat.
Using the Service Tool, a technician can ELECTRONICALLY:
1. Configure items like: airflow, heat pump options and configuration, pump or modulating valve operation, unit family, unit
size, etc.
AND
2. Diagnose the unit by operating it manually, performing control diagnostics, viewing dip switch configurations, or by
viewing fault history and operating conditions when a fault occurred.
The Service Tool connects to the DXM2 board with a 4-Wire Connector as shown below:
P1
Alarm Relay
Comp Relay
O
Y1
Y2
W
G
C
R
AL1
24Vdc
EH1 EH2
P6
R
C
Off On
JW3
A
OV
R
ESD
C
R
NSB
AL2
JW1
Acc1 Relay
Acc2 Relay
H
CO
M
NC1
NO
1
CO
M
NC2
NO
2
P3
CO
RV
RV
LT1 LT1 LT2 LT2
LP LP
HP
HP
P7
Status
Fault
R
R
CC
CCG
CO
S1
S2
1
12
1
4
Factory Use
(240V
ac)
Com
N.O.
Fan Enable
5
1/
2"
7"
6
1/
2"
5"
Use 4 mounting screws
#6 sheet metal screw 1” long
1.5
3/8” standof
f
Factory lo
w
voltage Mole
x
connection for unit harness
Factory lo
w
voltage Mole
x
connection for electric heat
harness
Micr
o
U1
Off On
P2
COH
COM
AO2
P11
Gnd
T1
P10
T2
T2
T3
T3
T4
T4
T5
P9
T5
T6
T6
A0-1
A0-2
Off On
S3
RV Relay
CCH Relay
Test
P5
B-
Gnd
P4
A+
24V
(240V
ac)
Fan Speed
N.O.
N.C.
12V
OUT Gnd
P8
IN
NC
P12
Note: There is only one T1 connection
1 2 3 4
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
AO1
Gnd
1
Service tool
connection
DXM2
Board
DXM2
DXM2
Board
Board
1.0 Connection
�
WARNING!
�
WARNING! Connecting wire harness while unit is powered on
or connecting backward may damage service tool.
