HVACopediaKeepRite · Heat pump
Phase monitor LED flashing 3-phase monitor - phase reversal
What the control is telling you
On 3-phase units, a flashing LED on the phase monitor means the supply phases are reversed. Off = no compressor call, on = normal.
Applies to: KeepRite N4H4/R4H4/WCH4/NXH5 3-phase heat pumps
Likely causes
- Two supply legs swapped
Test and repair steps
- Warning: lock out power first.
- Swap any two incoming supply legs at the disconnect.
- Confirm the LED goes steady on with a compressor call.
Models that show this code
5 models in KeepRite N4H4/R4H4/WCH4/NXH5 Heat Pump
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Source: KeepRite/ICP N4H4/R4H4/WCH4/NXH5 Installation Instructions 428 01 5107 10, Table 3 3-Phase Monitor LED Indicators, p.6. 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.