Error code reference
Lennox Heat Pump Error Code DS2 ON / DS1 OFF
High pressure lockout
High pressure lockout — high pressure switch has tripped 5 times during a single Y1 demand.
First step from the service manual
1) Remove any blockages or restrictions from coils and/or fans; check indoor and outdoor fan motor for proper current draws. 2) Check system charge using approach & subcooling temperatures. 3) Check system operating pressures and compare to unit charging charts. 4) Make sure all pressure switches and sensors have secure connections.
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
- Verified part numbers when replacement is required
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