Lennox XP21 Series Installation Instructions Manual page 46

Table 14. Compressor Fault and Alarm LED Codes and Related icomfort Touch
NOTE See notes 1 and 2 in table below for duration of fast / slow flashes and pause.
Heat Pump Control
icomfort
LEDs
Touch
Thermostat
DS15 DS13
Display
Yellow Red
Moderate/
Critical
Off On
Code 400
1 flash Critical Alert
Off
then pause Code 401
2 flashes Critical Alert
Off
then pause Code 402
Moderate
3 flashes
Alert Code
Off
then pause
403
506601−01
®
Possible
Condition
Cause(s)
Thermostat
Compressor
demand signal Y1
3
Alert internal
is present, but
overload trip
compressor not
running
Compressor is
Long run time. running extremely
long run cycles.
Indicates the
compressor
System
protector is open
pressure trip
or missing supply
power to the
compressor.
Compressor is
running less than
Short cycling
three minutes.
Solution
1
Compressor protector is open.
S
Check for high head pressure
S
Check compressor supply voltage
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.
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 connec-
tors
S
Check indoor blower control
S
Check thermostat wiring for open circuit
3
Evaporator coil is frozen.
S
Check for low suction pressure
S
Check for excessively low thermostat setting
S
Check evaporator airflow (coil blockages or re-
turn air filter)
S
Check ductwork or registers for blockage.
4
Faulty metering device.
S
Check TXV bulb installation (size, location and
contact)
S
Check if TXV/fixed orifice is stuck closed or de-
fective
5
Condenser coil is dirty
6
Liquid line restriction (filter drier blocked if present)
7
Thermostat is malfunctioning
S
Check thermostat sub−base or wiring for short
circuit
S
Check thermostat installation (location and lev-
el)
1
High head pressure.
S
Check high pressure switch if present in sys-
tem
S
Check if system is overcharged with refrigerant
S
Check for non−condensable in system
2
Condenser coil poor air circulation (dirty, blocked,
damaged).
3
Condenser fan is not running.
S
Check fan capacitor
S
Check fan wiring and connectors
S
Check fan motor for failure or blockage
4
Return air duct has substantial leakage.
1
Thermostat demand signal is intermittent.
2
Time delay relay or heat pump control is defective.
3
If high pressure switch is present, see flash code 2
information.
Page 46
® Thermostat Alert Codes
.
.
.
Clearing Status
Clears the error
after current is
sensed in the
run and start
winding for two
seconds, ser-
vice removed or
power reset.
Clears the error
after 30 consec-
utive normal run
cycles, or after
power reset.
Clears after four
consecutive
normal com-
pressor run
cycles, or after
power reset.
Clears after four
consecutive
normal com-
pressor run
cycles, or after
power reset.