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Heat pumps · Error codes · Atlantic
370-A3Atlantic

370-A3 on an Atlantic heat pump: Compressor temperature protection

Short answer

On an Atlantic heat pump, 370-A3 means: Compressor temperature protection. 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 23 September 2026 · 2 sources

What it means

On the Alféa Excellia A.I. / Excellia Duo A.I. (R410A split, 11-16)

The manual says: Compressor temperature protection.

Likely causes:

  • Refrigerant circuit protection (pressure/temperature out of range).

On the Alféa Extensa A.I. / Extensa Duo A.I. R32 (split, 3-10)

The manual says: Compressor temperature protection (permanent stoppage).

Likely causes:

  • Refrigerant circuit protection (pressure/temperature out of range).

Is it safe?

On the Alféa Excellia A.I. / Excellia Duo A.I. (R410A split, 11-16)

Does the heat pump stop?Yes
SeverityFault — clears by itself when the condition goes
Engineer needed?Yes

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

On the Alféa Extensa A.I. / Extensa Duo A.I. R32 (split, 3-10)

Does the heat pump stop?Yes
SeveritySafety lockout
Engineer needed?Yes

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

What you can check

  • Check the outdoor unit is not blocked by leaves, debris or snow.
  • Note the error number/LED pattern shown and give it to your installer.

What the engineer will check

  • Check refrigerant charge and leaks, expansion valve, pressure sensor/switch and airflow.
  • Check water flow through the plate heat exchanger.

Who to ask for: refrigeration (F-gas).

Certification: F-gas certification for refrigerant work.

What you might notice

Sources

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

Reviewed: 23 September 2026