Model reference
Lennox HP21-653
Heat Pump
1 document14 error codes7 service modes
Available documentation
Service Manual
- HP21 Service Literature53 pg
MyPros+ Max
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Error codes (14)
CodeMeaning
1Power loss for two electrical cycles (33-40 milliseconds), may suggest dirty or…10Option 2 safety device switch opens.11Compressor temperature sensor wires have shorted together.12Problem with the operation of the outdoor temperature sensor.14Control is in TEST mode; does not indicate a problem.15Mode jumper is not in place on the TSC-6 control.2Input indication acknowledging a change (jumper setting changes, delay…3Unsteady thermostat input indicating intermittent inputs from the room…4Low or high pressure switch opens after compressor has run for less than two…5Low or high pressure switch opens after compressor has run for more than two…6Compressor temperature exceeded its limit after running less than five minutes…7Compressor temperature exceeded its limit after running more than five minutes…8Option 1 safety device switch opens after compressor runs less than five…9Option 1 safety device switch opens after compressor runs more than five…Service modes (7)
- CMC1 Defrost Control Test Mode1
- HP21-3 Defrost Control Test ModeWith Y1 energized and 24V power applied to the board, place the termination temperature jumper…
- TSC-2 Manual Override (5-minute delay bypass)Press and release the manual override button on the TSC-2 control (after power-up delay of 10…
- TSC-2 Safety Dormant Lockout ResetTurn off power at the disconnect for at least 3 seconds
- TSC-6 Diagnostic Code Recall1
- TSC-6 Manual Override (5-minute delay bypass)Press and release the manual override button on the TSC-6 control.
- TSC-6 Test Mode1
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