Error code reference

Lennox Heat Pump Error Code DS2:OFF / DS1:ON

Low pressure lockout

Low pressure lockout — 5 low pressure faults during a single Y1 demand.

First step from the service manual

Remove blockages from coils/fans, check system charge using approach and subcooling, check operating pressures, verify pressure switch connections.

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

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DS2:OFF / DS1:ON on my Lennox Heat Pump

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Low pressure lockout — 5 low pressure faults

From Service Manual 286226, p.38:

1.Remove blockages from coils/fans, check system charge using approach and subcooling, check operating pressures, verify pressure switch connections.

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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