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Heat pumps · Error codes

Heliotherm heat pump error codes

Heliotherm · A niche brand in the UK. 9 codes across 1 product family, each taken from the manufacturer’s manuals. Heliotherm technical support ↗

Find a Heliotherm engineer →9 codes · reviewed 23 September 2026

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Type the code on your display or a word from its meaning. Each code opens its own page with what it means, whether it is safe and what you can check.

9 codes

CodeMeaningStops?Homeowner check?
COMPRESSOR-ERROR
High/low pressure difference falls below 3.5 bar
YesYes
DEFROST-MIN
Heating-side inlet temperature too low during defrost (error messages "H.outH.in Dif." / "Defrost min.")
YesYes
DEFROST-TIME
Defrosting takes too long (error message "Defrost time")
YesYes
DISCHARGE-MAX
Discharge (hot gas) maximum temperature limit exceeded
YesYes
ES-MOTOR-PROTECTION
Energy source (outdoor evaporator fan) motor protection tripped - protects ES drive from excessive current
YesYes
FLOW-RATE-MIN
Temperature difference between heat outlet and inlet too high - insufficient flow/energy for defrost
YesYes
HIGH-PRESSURE
Safety chain high pressure / condensing pressure limit exceeded
YesYes
LOW-PRESSURE
Evaporation pressure below safety-chain limit
YesYes
SUCTION-LINE-MIN
Suction line temperature monitoring - prevents heating water freezing during defrost/cooling
YesYes