Lennox Dave Signature Collection XC15 Installation Instructions Manual page 21

compressor to run. The yellow LED will begin flashing
a code 8 indicating a welded contactor.
3. Disconnect power from the compressor and 24VAC
power from the LSOM. While the LSOM is off, reattach
the wire to the Y terminal.
Status LED Condition
Green LED ON
Green LED Intermittent
Red LED ON
Red and Yellow LED
Status LED
Status LED Description
Condition
Thermostat demand signal Y1 is
Red LED ON present, but compressor not
running
Long Run Time − Compressor is
running extremely long run
Yellow Flash Code 1
cycles.
System Pressure Trip −
Discharge or suction pressure
Yellow Flash Code 2
out of limits or compressor
overloaded
Table 7. LSOM Module LED Troubleshooting Codes
Mis−wired Module
Indication
Module not powering up.
Module powers up only when
compressor runs.
LED is on but system and
compressor check OK.
Simultaneous flashing.
Table 8. LSOM System LED Troubleshooting Codes
Status LED Troubleshooting Information
1
Compressor protector is open.
2
Outdoor unit power disconnect is open.
3
Compressor circuit breaker or fuse(s) is open.
4
Broken wire or connector is not making contact.
5
Low or high pressure switch open if present in the system.
6
Compressor contactor has failed to close.
1
Low refrigerant charge.
2
Evaporator blower is not running.
3
Evaporator coil is frozen.
4
Faulty metering device.
5
Condenser coil is dirty
6
Liquid line restriction (filter drier blocked if present)
7
Thermostat is malfunctioning
1
High head pressure.
2
Condenser coil poor air circulation (dirty, blocked, damaged).
3
Condenser fan is not running.
4
Return air duct has substantial leakage.
4. Reapply power to the compressor and 24VAC power
to the LSOM; the yellow LED will flash the previous
code for 60 seconds and then turn off. If the yellow
LED does not function as described, refer to table 7 to
verify the wiring.
Status LED Troubleshooting Information
Determine/verify that both R and C module terminals are connected and
voltage is present at both terminals.
Determine if R and Y terminals are wired in reverse. Verify module's R and C
terminals have a constant source.
1
Verify Y terminal is connected to 24VAC at contactor coil.
2
Verify voltage at contactor coil falls below 0.5VAC when off.
3
Verify 24VAC is present across Y and C when thermostat demand signal is
present; if not present, R and C wires are reversed.
Indicates that the control circuit voltage is too low for operation. Verify R and C
terminals are supplied with 19−28VAC.
S
Check for high head pressure
S
Check compressor supply voltage
S
Check blower relay coil and contacts
S
Check blower motor capacitor
S
Check blower motor for failure or blockage
S
Check evaporator blower wiring and connectors
S
Check indoor blower control board
S
Check thermostat wiring for open circuit
S
Check for low suction pressure
S
Check for excessively low thermostat setting
S
Check evaporator airflow (coil blockages or return air filter)
S
Check ductwork or registers for blockage.
S
Check TXV bulb installation (size, location and contact)
S
Check if TXV is stuck closed or defective
.
.
S
Check thermostat sub−base or wiring for short circuit
S
Check thermostat installation (location and level)
S
Check high pressure switch if present in system
S
Check if system is overcharged with refrigerant
S
Check for non−condensable in system
S
Check fan capacitor
S
Check fan wiring and connectors
S
Check fan motor for failure or blockage
Page 21
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XC15 SERIES