Page 10
TABLE 2
DS2
Green
DS1
Red
Condition/Code
Possible Cause(s)
Solution
OFF
OFF
Power problem
No power (24V) to control termi-
nals R & 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. Control 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. Control will not
perform demand or time/temperature defrost operation. (System will still heat or
cool).
ON
ON
Circuit Board Failure
Indicates that control has internal component failure. Cycle 24 volt power to board.
If code does not clear, replace control.
FAULT & 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
1.
Remove any blockages or restrictions from
coils and/or fans. Check indoor and outdoor
fan motor for proper current draws.
2
OFF
ON
Low Pressure
LOCKOUT
Improper refrigerant charge in
system.
3.
Improper metering device
installed or incorrect operation
fan motor for proper current draws.
2.
Check system charge using approach & sub-
cooling temperatures.
3.
Check system operating pressures and
SLOW
Flash
OFF
High Pressure Fault
installed or incorrect operation
of metering device.
4.
Incorrect or improper sensor
location or connection to sys-
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
ON
OFF
High Pressure
LOCKOUT
location or connection to sys
tem.
have secure connections to system to prevent
refrigerant leaks or errors in pressure and
temperature measurements.
