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ICP · Heat pump

5 Open circuit

High severity ICP N4H3 Heat Pump

What the control is telling you

Compressor circuit is open - no current to the compressor.

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

  • Outdoor disconnect open
  • Breaker or fuses open
  • Contactor failed open
  • High pressure switch open needing manual reset
  • Open compressor supply wiring
  • Long protector reset time in extreme heat
  • Damaged compressor windings

Test and repair steps

  1. Warning: Turn off power before checking wiring.
  2. Check disconnect, breaker and fuses.
  3. Check the contactor closes.
  4. Reset the high pressure switch if it is the manual-reset type, and find why it tripped.
  5. Check compressor power wiring and terminals.
  6. Allow time for the internal protector to reset in high ambient.
  7. Check compressor windings with an ohmmeter.

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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.