Lennox XP19-024

Page 12
TABLE 4
System Operation Monitor LED Troubleshooting Codes
Status LED Condition Status LED Description Status LED Troubleshooting Information
Green Power" LED ON Module has power 24VAC control power is present at the module terminal.
Green Power" LED
OFF
Module not powering up Determine/verify that both R and C module terminals are connected
and voltage is present at both terminals.
Red Trip" LED ON System and compressor
check out OK
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, Y and C wires are reversed.
Thermostat demand signal
Y1 is present, but compres-
sor not running
NOTE − During 5-minute
delay in defrost board, the
red trip" LED will be on.
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 pressure switch open if present in the system.
6
Compressor contactor has failed to close.
Red Trip" & Yellow
Alert" LEDs Flashing
Simultaneous flashing. Indicates that the control circuit voltage is too low for operation.
Yellow Alert" Flash
Code 1*
Long Run Time − Compres-
sor is running extremely
long run cycles
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
.
Yellow Alert" Flash
Code 2*
System Pressure Trip or
Discharge Sensor Fault −
Discharge or suction pres-
sure out of limits or
compressor overloaded
1
Check high head pressure or discharge line sensor.
2
Condenser coil poor air circulation (dirty, blocked, damaged).
3
Condenser fan is not running.
4
Return air duct has substantial leakage.
5
If low pressure switch is present, see Flash Code 1 information.
Yellow Alert" Flash
Code 3*
Short Cycling − Compres-
sor is running only briefly
1
Thermostat demand signal is intermittent.
2
Time delay relay or control board is defective.
3
If high pressure switch is present, see Flash Code 2 information.
4
If discharge sensor is present, see Flash Code 2 information.
Yellow Alert" Flash
Code 4*
Locked Rotor
1
Run capacitor has failed.
2
Low line voltage (contact utility if voltage at disconnect is low).
3
Excessive liquid refrigerant in the compressor.
4
Compressor bearings are seized.
Yellow Alert" Flash
Code 5*
Open Circuit
1
Outdoor unit power disconnect is open.
2
Unit circuit breaker or fuse(s) is open.
3
Unit contactor has failed to close.
4
High pressure switch is open and requires manual reset.
5
Open circuit in compressor supply wiring or connections.
6
Unusually long compressor protector reset time due to extreme ambi-
ent temperature.
7
Compressor windings are damaged.
Yellow Alert" Flash
Code 6*
Open Start Circuit − Cur-
rent only in run circuit
1
Run capacitor has failed.
2
Open circuit in compressor start wiring or connections.
3
Compressor start winding is damaged.
Yellow Alert" Flash
Code 7*
Open Run Circuit − Current
only in start circuit
1
Open circuit in compressor start wiring or connections.
2
Compressor start winding is damaged.
Yellow Alert" Flash
Code 8*
Welded Contactor − Com-
pressor always runs
1
Compressor contactor failed to open.
2
Thermostat demand signal not connected to module.
Yellow Alert" Flash
Code 9*
Low Voltage − Control cir-
cuit <17VAC
1
Control circuit transformer is overloaded.
2
Low line voltage (contact utility if voltage at disconnect is low).
*Flash code number corresponds to a number of LED flashes, followed by a pause, and then repeated. Reset ALERT flash code
by removing 24VAC power from monitor; last code will display for 1 minute after monitor is powered on.