Error code reference

Lennox Heat Pump Error Code Green FAST Flash / Red ON

Discharge line temperature lockout (5 strikes): discharge line temperature fault occurred 5 times during a single Y1 demand; detects shorted sensor or high discharge temperatures.

SourceLennox HPXA16 Series Heat Pump - Service Manualp. 13

Lennox codes Lennox heat pump codes

Diagnostic procedure

The full Green FAST Flash / Red ON procedure

Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.

MyPros+ · DiagnosticsStep 1 preview

First diagnostic step

Cycle 24V power to board or short TEST pins 1-2 seconds to reset. Check discharge sensor and system operation.

SourceLennox HPXA16 Series Heat Pump - Service Manualp. 13

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Where this code is documented

1 manual in the MyPros+ library documents this code for Lennox heat pump.

Models covered by the manuals that document this code

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The full Green FAST Flash / Red ON procedure

Where this code is documented

Models covered by the manuals that document this code

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