Comfort Alert Diagnostic Module - Carrier 38AU Installation, Start-Up And Service Instructions Manual

Comfort Alert Diagnostic Module

The Comfort Alert Diagnostic Module (CADM) monitors
and analyzes 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. 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, thermostat Y1
or Y2, compressor contactor coil (common side) and
compressor power leads (from the compressor contactor).
Input Terminal
Control
Power
Control
Common
Cooling
Contactor
Coil
Line A T1
Line B T2
Line C T3
Control of the compressor contactor coil is through a
normally-closed (power on the module) contact 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. 32): POWER (green), ALERT (yellow), and
TRIP (red).
The POWER LED indicates the presence of control power
to the CADM.
The ALERT LED indicates an abnormal condition exists
in the system through a flash code. The ALERT LED will
blink a number of times consecutively, pause and the
repeat the process. The number of blinks, defined in Table
11, 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 requires that main power to the
38AU unit be recycled after the cause for the Alert
condition has been detected and corrected.
Voltage
R 24-V
C 24-V
Y 24-V
P 24-V
Line
Line
Line
POWER
(GRN)
ALERT
(YEL)
TRIP
(RED)
Fig. 32 - - CADM Housing/LED Locations
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 occur when the CADM detects a
thermostat demand at input Y but there is no power at the
compressor line terminals T1 or T2 or T3. This lockout
can occur due to a safety switch (LPS or HPS) opening
and de-energizing the
compressor-motor internal overload opens, or other
internal power interruption has occurred. 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
indicate wiring problems to the CADM. See Table 12 for
discussion of additional
troubleshooting instructions.
35
C10086
compressor contactor, the
LED flash codes and