Error code reference

Lennox Air Conditioner Error Code E434

Outdoor control has lost communications with the inverter for greater than 3 minutes (inverter code 53).

Outdoor control has lost communications with the inverter for greater than 3 minutes (inverter code 53).

First step from the service manual

Check all electrical connections and check for proper main power to inverter.

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

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E434 on my Lennox Air Conditioner

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Outdoor control has lost communications with

From Service Manual 873164, p.16:

1.Check all electrical connections and check for proper main power to inverter.

2.Measure door lock assembly resistance across the PTC terminals. Expected: ~200 ohms cold, rising sharply once energized.

3.Inspect strike and latch alignment. A warped door or misaligned strike prevents the switch stack from closing in the correct sequence.

Part W10810403

Door lock assembly

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