Carrier 38AUQ 25 Series Installation, Start-Up And Service Instructions Manual page 28

Comfort Alert Diagnostic Module
The Comfort Alert Diagnostic Module (CADM) monitors and an-
alyzes data from the Copeland Scroll three-phase compressor and
the thermostat demand. The CADM also provides a 3-minute anti-
recycle time delay to compressor cycling.
The CADM detects causes for electrical and system related fail-
ures. Flashing LEDs communicate the Alert codes to guide ser-
vice technicians in accurately and quickly troubleshooting the sys-
tem and determining root cause for the failure.
Inputs to the CADM include 24-vac power, demand signal Y,
compressor contactor coil (common side) and compressor power
leads (from the compressor contactor).
INPUT TERMINAL
Control Power
Control Common
Demand
Contactor Coil
Compressor T1
Compressor T2
Compressor T3
Control of the compressor contactor coil is through a contact be-
tween terminals P and C.
Communications of status and alert conditions is through three
LEDs located on the top edge of the module housing (see Fig. 27):
POWER (green), ALERT (yellow), and TRIP (red).
The POWER LED indicates the presence of control power to the
CADM.
VOLTAGE
R 24-V
C 24-V
Y 24-V
P 24-V
T1 Line
T2 Line
T3 Line
Power
(GRN)
POWER
Alert
(YEL)
ALERT
TRIP
Trip
(RED)
Fig. 27 — CADM Housing/LED Locations
The ALERT LED indicates an abnormal condition exists in the
system through a flash code. The ALERT LED will blink a num-
ber of times consecutively, pause and the repeat the process. The
number of blinks, defined in Table 14, correlates to a particular
abnormal condition; troubleshooting tips are provided for each
Alert code. Reset of the ALERT may be automatic or manual. If
the fault condition causing the Alert is self-corrected, the Alert
code will be removed and the CADM will automatically reset and
allow the system to restart normally. Manual reset for lockouts re-
quires that main power to the 38AUQ unit be recycled after the
cause for the Alert condition has been detected and corrected.
The TRIP LED indicates either a time-delay period is currently
active (RED LED is blinking) or the module has locked out the
compressor (RED LED is on steady). A lockout condition will oc-
cur for some faults as identified in Table 14. Reset of the TRIP
LED requires that unit main power be recycled after the loss of
power to the compressor condition has been detected and
corrected.
Simultaneous Blinking of YELLOW and RED LEDs indicates
control power input to the CADM is low. Check control circuit
transformer and wiring.
Troubleshooting the CADM Wiring – Flashing LEDs also indi-
cate wiring problems to the CADM. See Table 15 for discussion
of additional LED flash codes and troubleshooting instructions.
28
Comfort Alert
™
Commercial Diagnostics
Green LED - 24VAC Power
Yellow LED - Flash Code
2 System Pressure Trip
3 Short Cycling
4 Locked Rotor
5 Open Circuit
T1
6 Missing Phase
7 Reverse Phase
8 Welded Contactor
9 Low Voltage
Red LED - Protector Open
or no compressor power
Active Protection T2
PROT breaks 24VAC common
leg of compressor contactor coil
Reset codes and PROT lockout
by removing 24VAC to module
For Two-Stage Applications:
T3
DC SOL operating range: 4-18VAC
Compressor second stage is
energized when YA & Y2 are 24VAC
and Alert and Trip LEDs are off
EMERSON ™
Climate Technologies