Error code reference

Lennox Heat Pump Error Code 1

Long Run Time

Long Run Time – Compressor is running extremely long run cycles, indicating possible low charge, frozen evaporator coil, faulty metering device, dirty condenser coil, liquid line restriction, or thermostat malfunction.

First step from the service manual

Check for low refrigerant charge, verify evaporator blower is running, check for frozen evaporator coil, check metering device, inspect condenser coil for dirt, check for liquid line restriction.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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Step-by-step tests with expected resistance, voltage, and continuity values
Wiring diagram references and connector pinouts from the OEM service manual
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Long Run Time – Compressor is running extremely

From Service Manual 979405, p.17:

1.Check for low refrigerant charge, verify evaporator blower is running, check for frozen evaporator coil, check metering device, inspect condenser coil for dirt, check for liquid line restriction.

2.Inspect the exhaust duct from the unit to the wall cap. A crushed or lint-blocked duct is the most common cause of airflow-related faults.

3.Measure static pressure at the blower housing with the lint screen removed. Expected: ≥ 1.0 in. w.c. in a still-air test.

Part W10861225

Blower wheel and housing

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First step from the service manual

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