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Heat pumps · Error codes · Advantix S.p.A
E891Advantix S.p.A

E891 on an Advantix S.p.A heat pump: One or more compressor supply phases absent

Short answer

On an Advantix S.p.A heat pump, E891 means: One or more compressor supply phases absent. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.

Reviewed 24 September 2026 · 4 sources

What it means

On the MAXA i-290 (Gamma i-290)

The manual says: One or more compressor supply phases absent.

Part involved: compressor inverter drive board.

On the MAXA i-32V5

The manual says: Driving protection-output phase loss.

Part involved: compressor inverter drive board.

On the MAXA i-32V5 MIDI (i-32V5H Midi)

The manual says: Compressor not connected.

Part involved: compressor inverter drive board.

On the MAXA i-HPV5H

The manual says: Compressor not connected.

Part involved: compressor inverter drive board.

Is it safe?

Does the heat pump stop?Yes
Engineer needed?Yes

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

Resetting itself: unknown.

What you can check

  • Note the code shown on the controller and the model number on the unit's rating label before contacting your installer.
  • Check that the heat pump's isolator and consumer-unit breaker are on; do not open any casing.

What the engineer will check

  • Check supply voltage and phase at the unit terminals.
  • Check compressor U/V/W connections and compressor winding resistance.
  • Check drive board heatsink cooling and fan.
  • Replace the inverter/driver board if faults persist.

Who to ask for: Heat pump engineer.

Certification: Heat pump installer competence; F-gas and flammable-refrigerant (R32/R290) handling competence for any refrigerant-circuit work.

What you might notice

Sources

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

Reviewed: 24 September 2026