Short answer
On the Hayward/Summit heat-pump models listed in the linked guide, LP indicates an open low-pressure switch. Check the exact model plate, outdoor temperature, and whether the fan runs. A refrigerant leak or electrical fault needs qualified service. Stop if LP persists; do not open the sealed circuit or order a switch from this code alone.
Checks for Hayward LP
- Match the model plate to the models covered by the Hayward/Summit guide.
- Record outdoor temperature and whether the fan starts when the heat pump runs.
- Record whether LP appears immediately or only after a short run.
Proof to capture before ordering parts
- Photo of the complete display and when the code appeared
- Model and serial plate, including controller revision if visible
- Filter, pump, bypass position, and pad context
Stop rule
Stop if LP persists. Refrigerant, switch, fan-electrical, and internal tests belong to a qualified servicer.
Not a diagnosis. Confirm the exact model and current manufacturer procedure before repair or parts ordering. Do not bypass safeties.
Common questions
What does Hayward LP mean on a guide-listed heat pump?
LP indicates the low-pressure switch is open on the models covered by the linked Hayward/Summit guide.
What should I check first for LP?
Match the model plate to the models covered by the Hayward/Summit guide. Record outdoor temperature and whether the fan starts when the heat pump runs. Record whether LP appears immediately or only after a short run.
When should I stop checking LP?
Stop if LP persists. Refrigerant, switch, fan-electrical, and internal tests belong to a qualified servicer.
Related codes
Manufacturer source
Hayward/Summit Heat Pump Troubleshooting Guide (PDF). Last reviewed: . Consult the guide's model list before using these checks.
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