Error code reference

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

High pressure lockout

High pressure lockout — 5 high pressure faults during a single Y1 demand.

First step from the service manual

Remove blockages from coils/fans, check system charge, check operating pressures, verify all pressure switch and sensor connections.

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

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

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High pressure lockout — 5 high pressure faults

From Service Manual 173274, p.46:

1.Remove blockages from coils/fans, check system charge, check operating pressures, verify all pressure switch and sensor 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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