Lennox XC21 User Manual

Page 37
XC21 SERIES
Table 10. Compressor Alert Codes (A175 Main Control LEDs and Communicating Thermostat User Interface)
Outdoor A175 Main
Control LEDs
icomfort
Toucht
Thermostat
Display
Condition
Possible
Cause(s)
Solution
Clearing Status
DS15
Yellow
DS13
Red
OFF ON
Moderate/
Critical Alert
Code 400
Compressor
Internal
Overload Trip
Thermostat
demand signal Y1
is present, but
compressor not
running
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 pres-
ent in the system.
6
Compressor contactor has failed to close.
Clears the error after
current is sensed in the
run and start winding for
two seconds, service
removed or power reset.
1 Flashes
then
Pause
OFF
Critical Alert
Code 401
Long run time.
Compressor is
running extremely
long run cycles.
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
connectors
S Check indoor blower control
S Check thermostat wiring for open cir-
cuit
3
Evaporator coil is frozen.
S Check for low suction pressure
S Check for excessively low thermostat
setting
S Check evaporator airflow (coil block-
ages or return air filter)
S Check ductwork or registers for block-
age.
4
Faulty metering device.
S Check TXV bulb installation (size,
location and contact)
S Check if TXV/fixed orifice is stuck
closed or defective
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 (loca-
tion and level)
Clears the error after 30
consecutive normal run
cycles, or after power
reset.
2 Flashes
then
Pause
OFF
Critical Alert
Code 402
System
Pressure Trip
Indicates the
compressor
protector is open
or missing supply
power to the
compressor.
1
High head pressure.
S Check high pressure switch if present
in system
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 block-
age
4
Return air duct has substantial leakage.
Clears after four
consecutive normal
compressor run cycles,
or after power reset.

Lennox XC21 Specifications

General

SEER Rating	up to 21.00
Sound Rating	as low as 69 dB
Refrigerant	R-410A
Energy Star Certified	Yes
Compressor Type	Two-Stage
Cooling Capacity (BTU/h)	24000-54000
Warranty	10-Year Limited Warranty on compressor