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Heat pumps · Error codes · Immergas
E8Immergas · MAGIS M monobloc R32 (M4-M30 T) - sold in UK as Alpha Magis M

E8 on an Immergas MAGIS M monobloc R32 - sold in UK as Alpha Magis M: Water flow fault

Short answer

On an Immergas heat pump, E8 means: Water flow fault. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.

Reviewed 23 September 2026 · 1 source

What it means

The manual says: Water flow fault.

Likely causes:

  • Shut-off valves not fully open.
  • Water filter needs cleaning.
  • Air in system.
  • Water pressure below 1 bar.
  • Pump speed not at maximum.
  • Expansion vessel damaged.
  • Hydraulic pressure drop too high for pump.
  • During defrost: backup-heater supply wiring/fuses.
  • Pump or PCB fuse blown.

Is it safe?

Does the heat pump stop?Not stated
Engineer needed?Yes

The manual does not say whether the heat pump stops.

Manual reset: Manual 13.4: reset the safety device by switching the unit off and back on; if this fails contact your local dealer.

What you can check

  • Check the system pressure gauge (manual: water pressure must be above 1 bar with cold water).
  • Note the code on the control panel and contact the installer / Alpha-Immergas authorised service.
  • The manual says to reset the safety device by switching the unit off and back on; if the reset fails, contact the dealer - do not keep resetting.

What the engineer will check

  • Shut-off valves not fully open.
  • Water filter needs cleaning.
  • Air in system.
  • Water pressure below 1 bar.
  • Pump speed not at maximum.
  • Expansion vessel damaged.
  • Hydraulic pressure drop too high for pump.
  • During defrost: backup-heater supply wiring/fuses.
  • Pump or PCB fuse blown.

Who to ask for: heat pump engineer.

Certification: Electrical competence.

What you might notice

Sources

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

Reviewed: 23 September 2026