34
Comfort Alert Diagnostic Module
The Comfort Alert Diagnostic Module (CADM ) monitors
and analyzes data from the Copeland Scroll three- ph as e
compressor and the thermostat demand. The CADM also
prov id es a 3-minute anti-r ecycle time delay to compr es s or
cycling. Each compressor has a separate CADM module.
The CADM detects causes for electrical and system
related failures without any sensors. Flashing LEDs
communicate the Alert codes to guide service technicians
in accurately and quickly troubleshooting the system and
determining root cause for the failure.
Inputs to the CADM include 24-vac power, thermosta t Y1
or Y2, compressor contac tor coil (common side) and
compressor power leads (from the compressor contactor).
Input Te r m i n a l Voltage
Control
Power
R 24-V
Control
Common
C 24-V
Cooling Y 24-V
Contactor
Coil
P 24-V
Line A T1 Line
Line B T2 Line
Line C T3 Line
Control of the compressor conta ctor coil is through a
normally-closed (power on t he module) conta ct between
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 (yell ow), and
TRIP (red).
The POWER LED indica tes the presence of control power
to the CADM.
The A LERT LED indicates an abnormal condition exists in
the system through a flash code. The ALERT LED will
blink a n umb er of times consecu tively, pau s e and the rep eat
the process. The number of blinks, defined in Table 13,
correlates to a particular abnormal condition; troubleshooting
tips are provided for each Aler t code. Reset of the ALERT
may be automatic or manual. If the fault condition causing
the Alert is self -co rr ected, the Alert code will be removed
and the CA D M will automatically res et and allow the
system to restart normally. Manual reset requires that main
pow er to the 38AU unit be recycled after the cause for the
Alert cond itio n has been detected and corr ected.
POWER
(GRN)
ALERT
(YEL)
TRIP
(RED)
C10086
Fig. 27 -- CADM Housing/LED Locations
The TRIP LED indicates either a time-delay period is
current ly active (RED LED is blinking) or the module has
locke d out the compressor (RED LED is on steady). A
lockout condition will occur when t he CADM detects a
thermostat demand at input Y but there is no power at the
compressor line terminals T1 or T2 or T 3. This lockout
can occur due to a safety switch (L PS or HPS) opening
and de-energizing the compressor contactor, the
compressor-motor interna l overload opens, or other
internal power interruption has occurred. Reset of the
TRIP LED requires that unit main power be recycle d 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 i s l ow. Check
control circuit transformer and wiring.
Troubleshooting the CADM Wiring – Flashing LEDs also
indicate wiring problems to the CADM. See Table 14 for
discussion of additional LED flash codes and
troubleshooting instructions.
38AU
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