The display shows H1; the unit does not blow warm air for several minutes in heating mode.

Note: H1 on many Tristar heat pump models indicates a normal defrost operation, not a fault.

Steps:

• Wait 5–10 minutes: The unit will stop the indoor fan and reverse cycle to melt ice on the outdoor coil. Warm air will resume after defrost completes.
• Check outdoor unit: Ensure the outdoor coil is not buried in snow or heavy ice. Clear snow and ice around the base and grille.
• Improve drainage: Make sure meltwater can drain away and not refreeze around the unit.

When to call a technician: If H1 remains for an unusually long time or heating never resumes, the defrost sensor or control may be faulty and should be checked professionally.