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Heat pumps · Error codes · Atlantic
516Atlantic

516 on an Atlantic heat pump: Heat pump missing - check the wiring between X60 and the interface board

Short answer

On an Atlantic heat pump, 516 means: Heat pump missing - check the wiring between X60 and the interface board. 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 · 3 sources

What it means

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

The manual says: Heat pump missing - check the wiring between X60 and the interface board.

Likely causes:

  • Loss of connection between controller and heat pump.

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

The manual says: Heat pump missing.

Likely causes:

  • Loss of connection between controller and heat pump.

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

The manual says: Heat pump missing.

Likely causes:

  • Loss of connection between controller and heat pump.

Is it safe?

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.

What you can check

  • Check the heat pump isolator and consumer-unit breakers are on (do not open any casing).
  • Note the error number/LED pattern shown and give it to your installer.

What the engineer will check

  • Check the wiring between X60 and the interface board.

Who to ask for: heat pump controls / electrical.

What you might notice

Sources

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

Reviewed: 23 September 2026