Error code reference

Lennox Furnace Error Code E 226

High pressure switch failed closed.

First step from the service manual

Check operation of high pressure switch closing on heat call. Measure operating pressure. Inspect vent and combustion air inducer for correct operation and restriction. Resumes normal operation after fault is cleared.

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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E 226 on my Lennox Furnace

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High pressure switch failed closed

From Service Manual 269853, p.25:

1.Check operation of high pressure switch closing on heat call. Measure operating pressure. Inspect vent and combustion air inducer for correct operation and restriction. Resumes normal operation after fault is cleared.

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

Get the full diagnostic procedure for E 226.

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