Lennox XP21 Series User Manual

Page 16
XP17
System fault and lockout LED (DS11 / DS14) alarm codes takes precedence over system status LED codes (cooling, heating stages or
defrost/dehumidification). Only the latest active LED fault or lockout alarm code if present will be displayed. If no fault or lockout codes are active, then
system status LEDs are routinely displayed. See notes 1 and 2 in table below for duration of fast / slow flashes and pause.
Heat Pump Control
LEDs
SolutionPossible Cause(s)Condition
iComfortt
-enabled
Thermostat
Display
DS11
Green
SolutionPossible Cause(s)Condition
iComfortt
-enabled
Thermostat
Display
DS14 Red
DS11
Green
SolutionPossible Cause(s)Condition
iComfortt
-enabled
Thermostat
Display
DS14 Red
Slow flash On
Moderate
Alert Code
414
Discharge line
temperature fault
This code indicates high discharge temperatures. If the discharge line temperature
exceeds a temperature of 279ºF (137ºC) during compressor operation, the control
will de-energize the compressor contactor output (and the defrost output if active).
The compressor will remain off until the discharge temperature has dropped below
225ºF (107ºC).
Fast flash On
Critical Alert
Code 415
Discharge line
temperature
lockout
Off Fast flash
Moderate /
Critical Alert
Code 417
Discharge sensor
fault
The heat pump control (A175) detects open or short sensor or out of temperature
sensor range. This fault is detected by allowing the unit to run for 90 seconds
before checking sensor resistance. If the sensor resistance is not within range
after 90 seconds, the control will raise the alarm.
3 fast
flashes
then
pause
Off
Moderate /
Critical Alert
Code 418
W output
hardware fault
When auxiliary heat output is detected as active. Fault in the heat pump control.
Replace heat pump control.
3 fast
flashes
then
pause
On
Moderate /
Critical Alert
Code 419
W output
hardware fault
lockout
If heat pump control recognizes five output hardware fault events during a single
cooling demand, the heat pump control will initiate a lockout.
Off
3 fast
flashes
then
pause
Critical Alert
Code 421
W external
miswire fault
When auxiliary heat output is detected as active after compressor has been
de-energized.
Simultaneous fast
flashes then pause
None
Second-stage
heat lock-in
If the unit is in non-communicating mode and it goes to second stage due to ambi
ent temperature being below second stage lock-in setting (E48).
Fast simultaneous flashing of DS11,
DS13, DS14 and DS15
OEM mode Factory test mode.
1. Pause duration is two (2) seconds.
2. Fast flash duration is 1/2 second. Slow flash duration is one (1) second.
Table 6. Compressor Fault and Lockout LED Codes and Related iComfortt-Enabled Thermostat Alert Codes
NOTE — See notes 1 and 2 in table below for duration of fast / slow flashes and pause.
Heat Pump Control
LEDs
iComfortt
-enabled
Thermostat
Display
Condition
Possible
Cause(s)
Solution
Clearing Sta
tus
DS15
Yellow
DS13
Red
Off On
Moderate/
Critical
3
Alert
Code 400
Compressor
internal
overload trip
Thermostat
demand signal
Y1 is present, but
compressor not
running
1
Compressor protector is open.
 Check for high head pressure
 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.
Clears the error
after current is
sensed in the
run and start
winding for two
seconds, ser
vice removed or
power reset.

Lennox XP21 Series Specifications

General

Brand	Lennox
Model	XP21 Series
Category	Heat Pump
Language	English