SolarpunkHomes
Sign inCall us · +44 7510 081687
Heat pumps
Heat pumps · Error codes · Immergas
P1Immergas · MAGIS M monobloc R32 (M4-M30 T) - sold in UK as Alpha Magis M

P1 on an Immergas MAGIS M monobloc R32 - sold in UK as Alpha Magis M: High pressure protection switch

Short answer

On an Immergas heat pump, P1 means: High pressure protection switch. 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: High pressure protection switch.

Likely causes:

  • Low water flow / air in system.
  • Water pressure < 0.1 MPa.
  • Refrigerant overcharge.
  • EXV blocked.
  • DHW: tank coil too small.
  • Cooling: coil protection not removed / coil dirty.

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 outdoor unit is not blocked by leaves, debris or snow and has clear airflow.
  • 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

  • Low water flow / air in system.
  • Water pressure < 0.1 MPa.
  • Refrigerant overcharge.
  • EXV blocked.
  • DHW: tank coil too small.
  • Cooling: coil protection not removed / coil dirty.
  • Refrigerant-circuit diagnosis/charging (F-gas certified engineer).

Who to ask for: heat pump / refrigeration engineer.

Certification: F-gas certification for refrigerant circuit work (unit is hermetically sealed; installation needs no F-gas per Alpha).

What you might notice

Sources

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

Reviewed: 23 September 2026