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ICP · Heat pump

1 Long run time

Medium severity ICP N4H3 Heat Pump

What the control is telling you

Compressor is running extremely long cycles.

Applies to: ICP N4H3 R-410A split heat pump (manual 428 01 5103 02); Comfort Alert codes apply only to units factory-fitted with the Comfort Alert module

Likely causes

  • Low refrigerant charge
  • Indoor blower not running
  • Indoor coil frozen
  • Faulty metering device
  • Dirty outdoor coil
  • Liquid line restriction (blocked filter-drier)
  • Thermostat malfunction

Test and repair steps

  1. Check the indoor blower runs and filters are clean.
  2. Check for a frozen indoor coil; thaw and find the cause.
  3. Clean the outdoor coil.
  4. Check charge by subcooling (TXV) or superheat (piston) as the manual specifies.
  5. Check the liquid line filter-drier for temperature drop (restriction).
  6. Check the metering device and the thermostat.

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Source: ICP N4H3 Installation Instructions 428 01 5103 02, Comfort Alert Diagnostics Codes (Figure 18), p.20. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.