Error code reference

Lennox Heat Pump Error Code DS2:SLOW Flash / DS1:OFF

High pressure fault

Lennox codes Lennox heat pump codes

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Diagnostic procedure

The full DS2:SLOW Flash / DS1:OFF procedure

Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.

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First diagnostic step

Remove blockages or restrictions from coils and fans; check system charge; check metering device operation; verify pressure switch and sensor connections.

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More steps, wiring diagram references, and verified part numbers

Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.

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The full DS2:SLOW Flash / DS1:OFF procedure

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