Page 39
XP14 SERIES
DEFROST BOARD DIAGNOSTICS (XP14-XXX-230-01 and later)
See table 13 to determine defrost board operational conditions and to diagnose cause and solution to problems.
Table 13. Defrost Control Board Diagnostic LEDs (XP14-XXX-230-01 through 07)
DS2
Green
DS1
Red
Condition/Code
Possible Cause(s)
Solution
OFF
OFF
Power problem
No power (24V) to board terminals R
and C or board failure.
1
Check control transformer power (24V).
2
If power is available to board and LED(s) do not
light, replace board.
Simultaneous
SLOW Flash
Normal operation
Unit operating normally or in standby
mode.
None required.
Alternating SLOW
Flash
5-minute anti-short cycle
delay
Initial power up, safety trip, end of
room thermostat demand.
None required (Jumper TEST pins to override)
Simultaneous
FAST Flash
Ambient Sensor Problem
Sensor being detected open or shorted or out of temperature range. Board will revert to time/
temperature defrost operation. (System will still heat or cool).
Alternating
FAST Flash
Coil Sensor Problem
Sensor being detected open or shorted or out of temperature range. Board will not perform
demand or time/temperature defrost operation. (System will still heat or cool).
ON
ON
Circuit Board Failure
Indicates that board has internal component failure. Cycle 24 volt power to board. If code does
not clear, replace board.
FAULT and LOCKOUT CODES
(Each fault adds 1 strike to that code's counter; 5 strikes per code = LOCKOUT)
OFF
SLOW
Flash
Low Pressure Fault
1
Restricted air flow over indoor or
outdoor coil.
2
Improper refrigerant charge in
system.
3
Improper metering device installed or
incorrect operation of metering
device.
4
Incorrect or improper sensor location
or connection to system.
1
Remove any blockages or restrictions from coils
and/or fans. Check indoor and outdoor fan motor for
proper current draws.
2
Check system charge using approach and subcool
ing temperatures.
3
Check system operating pressures and compare to
unit charging charts.
4
Make sure all pressure switches and sensors have
secure connections to system to prevent refrigerant
leaks or errors in pressure and temperature mea
surements.
OFF
ON
Low Pressure
LOCKOUT
SLOW
Flash
OFF
High Pressure Fault
ON
OFF
High Pressure
LOCKOUT
SLOW
Flash
ON
Discharge Line Temperature
Fault
This model does not have a defrost line sensor, therefore this code is not applicable.
FAST
Flash
ON
Discharge Line Temperature
LOCKOUT
OFF
Fast
Flash
Discharge Sensor Fault
The XP14 series units does not use a defrost line sensor. However, a resistor is installed
across pins P4-1 and P4-2. If the resistor is missing or damage then this fault code will be
displayed.
Fast
Flash
OFF
Discharge Sensor
LOCKOUT
This model does not have a defrost line sensor, therefore this code is not applicable.
