Error code reference

Lennox Hvac Error Code 302

The R to O jumper was not removed on the air-handler control board.

The R to O jumper was not removed on the air-handler control board.

First step from the service manual

Cut/remove R to O jumper. Applicable with non-communicating outdoor unit with communicating indoor unit. The fault clears after the R to O jumper is cut/removed.

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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