E488 on a Samsung heat pump: AC Input Voltage Sensor Error

What it means

The manual says: AC Input Voltage Sensor Error.

Part involved: Inverter PCB / compressor.

When it shows: Unit self-diagnosis: AC Input Voltage Sensor Error.

Likely causes:

• Inverter/compressor drive fault: supply voltage issue, compressor wiring/winding, IPM/PFC/sensor fault on inverter PCB, refrigerant or airflow problem causing overcurrent/overheat.
• Engineer checks per Samsung service manual: Check AC input voltage sensing on inverter PCB and supply voltage.

Is it safe?

The heat pump stops until the fault clears or is reset.

Resetting itself: unknown.

Manual reset: unknown.

What you can check

• Note the full error code shown on the controller; check the heat pump breaker/isolator in the consumer unit is ON; check the outdoor unit is not blocked by leaves, debris or snow and air can flow freely; then contact your installer or Samsung service; Samsung manuals do not describe a homeowner reset for this code.

What the engineer will check

• Check AC input voltage sensing on inverter PCB and supply voltage. Any work inside casings, on PCBs, wiring, sensors, pumps, valves or refrigerant is engineer-only.

Who to ask for: Heat pump engineer with electrical and refrigeration competence; R290 (A3 flammable refrigerant) competence.

Certification: Competent electrical worker (BS 7671); F-gas certification if refrigerant circuit is opened; R290/flammable refrigerant handling training (e.g. hydrocarbon refrigerant course).

What you might notice

• Sym:error-code
• No heating
• Keeps stopping / cutting out
• Intermittent fault

Sources

• EHS R290 Mono Outdoor Unit Installation Manual AE***CXYD** (EU) DB68-12496A-03 ↗ · DB68-12496A-03 · page p.24 · Reviewed 23 September 2026

A code explains what the controller detected, not a confirmed root cause.

Reviewed: 23 September 2026