Error code reference

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

Discharge line temperature lockout

Discharge line temperature lockout — 5 high discharge line temperature faults during a single Y1 demand.

First step from the service manual

Cycle OFF 24V power to board or short TEST pins 1-2 seconds to reset. Check system charge, airflow, and sensor connections.

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

MyPros+ Max

$29/month · Cancel anytime · Or $9.95 3-day pass

M+

M+ Max·Lennox Heat Pump

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

M+

Discharge line temperature lockout — 5 high

From Service Manual 319191, p.43:

1.Cycle OFF 24V power to board or short TEST pins 1-2 seconds to reset. Check system charge, airflow, 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

78,000+ service manuals · 160,000+ error codes · 55+ brands

$29/month · Cancel anytime · Or $9.95 3-day pass