Carrier Gemini 38AU Series Installation, Start-Up And Service Instructions Manual page 34

STATUS LED
Green "POWER"
Red "TRIP" LED On Solid
Red "TRIP" LED Flashing
Module locks out compressor when compressor damaging ALERT code appears.
Lockout ALERT codes are noted in the Status LED Description.
During a compressor lock out, 24VAC power must be removed from module to manually reset.
Yellow "ALERT" LED On Solid
Yellow "ALERT" Flash Code 2
Yellow "ALERT" Flash Code 3
Yellow "ALERT" Flash Code 4 Locked Rotor LOCKOUT
Yellow "ALERT" Flash Code 5 Open Circuit
Yellow "ALERT" Flash Code 6 Missing Phase LOCKOUT
Yellow "ALERT" Flash Code 7 Reverse Phase LOCKOUT
Yellow "ALERT" Flash Code 8
Yellow "ALERT" Flash Code 9 Low Voltage Control circuit
MISWIRED MODULE INDICATION
Green LED is not on,
module does not power up
Green LED Intermittent,
module powers up only
when compressor runs
TRIP LED is on but system
and compressor check OK
TRIP LED and ALERT LED
flashing together
ALERT Flash Code 3
(Compressor Short Cycling)
displayed incorrectly
ALERT Flash Code 5 or 6
(Open Circuit, Missing Phase)
displayed incorrectly
Alert Flash Code 8
(Welded Contactor)
displayed incorrectly
Table 20 — LED Status Codes
STATUS LED
DESCRIPTION
Module has power Supply voltage is present at module terminals
1. Compressor protector is open
2. Condensing unit power disconnect is open
Thermostat demand signal
3. Compressor circuit breaker or fuse(s) is open
Y is present, but the
4. Broken supply wires or connector is not making contact
compressor is not running.
5. Compressor power wires not routed through Comfort Alert
6. Compressor contactor has failed open
The anti-short cycle timer (3 minutes) in module is preventing compressor restart.
A short circuit or over 1. Compressor contactor coil shorted
current condition exists on 2. Electrical load too high for PROT circuit (maximum 1 Amp)
PROT terminal. 3. 24 V AC wired directly to PROT terminal
1. High head pressure
2. Condenser coil poor air circulation (dirty, blocked, damaged)
3. Condenser fan is not running
4. If low pressure switch is open:
System Pressure Trip
Discharge pressure out of
limits LOCKOUT
Short Cycling Compressor
is running only briefly (four 1. Loose connection between thermostat Y1 and CADM Y terminal.
consecutive cycles of less 2. Unit short-cycling on thermostat
than three minutes each) 3. System or control board defective
LOCKOUT
1. Low line voltage to compressor
2. Excessive liquid refrigerant in compressor
3. Compressor bearings are seized
1. Condensing unit power disconnect is open
2. Compressor circuit breaker or fuses are open
3. Compressor contactor has failed open
4. High pressure switch is open and requires manual reset
5. Broken supply wires or connector is not making contact
6. Unusually long compressor protector reset time due to extreme ambient temperature
7. Compressor windings are damaged
1. Compressor fuse is open on one phase
2. Broken wire or connector on one phase
3. Compressor motor winding is damaged
4. Utility supply has dropped one phase
1. Compressor running backward due to supply phase reversal
Welded Contractor 1. Compressor contactor has failed closed
Compressor always runs 2. Thermostat demand signal not connected to module
1. Control circuit transformer is overloaded
< 18VAC 2. Low line voltage to compressor
Table 21 — CADM Troubleshooting
RECOMMENDED TROUBLESHOOTING ACTION
Determine if both R and C module terminals are connected. Verify voltage in present at module's R and C
terminals.
NOTE: The CADM requires a constant nominal 24VAC power supply. The wiring to the module's R and C
terminals must be directly from the control transformer. The module cannot receive its power from another
device that will interrupt the 24VAC power supply. See Appendix B Wiring Diagrams.
Determine if R and Y terminals are wired in reverse. Verify module's R and C terminals have a constant
source. See "NOTE" above for details on R and C wiring.
Verify Y terminal is wired properly per the 38AU wiring diagram (see Appendix B Wiring Diagrams). Verify
voltage at contactor coil falls below 0.5VAC when off. Verify 24VAC is present across Y and C when
thermostat demand signal is present. If not, R and C are reverse wired.
Verify R and C terminals are supplied with 19-28VAC.
Verify Y terminal is connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below
0.5VAC when off.
Check that compressor T1 and T3 wires are through module's current sensing holes. Verify Y terminal is
connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below 0.5VAC when off.
Determine if module's Y terminal is connected. Verify Y terminal is connected to 24VAC at contactor coil.
Verify 24VAC is present across Y and C when thermostat demand signal is present. If not, R and C are
reverse wired. Verify voltage at contactor coil falls below 0.5VAC when off.
STATUS LED TROUBLESHOOTING INFORMATION
a. Low refrigerant charge
b. Evaporator blower is not running
c. Evaporator coil is frozen
d. Faulty metering device
e. Condenser coil is dirty
f. Liquid line restriction (filter drier blocked if present)
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