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Heat pumps · Error codes · Warmflow
E11Warmflow

E11 on a Warmflow heat pump: High Pressure Protection

Short answer

On a Warmflow heat pump, E11 means: High Pressure Protection. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.

Reviewed 23 September 2026 · 3 sources

What it means

The manual says: High Pressure Protection.

Part involved: pressure switch / compressor discharge-suction.

Likely causes:

  • The high pressure switch in the refrigeration circuit has been tripped.

Is it safe?

Does the heat pump stop?Yes
Engineer needed?Yes

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

What you can check

  • Note the exact code shown on the controller (a photo helps) and report it to your installer or the manufacturer's service line.
  • Check the heat pump's supply breaker/isolator at the consumer unit is on (do not open any casing).
  • Check the outdoor unit is not blocked by debris/snow and has its required clearances.

What the engineer will check

  • Check the operation of the high pressure switch and refrigeration circuit in terms of gas pressure.

Who to ask for: refrigeration.

Certification: F-gas certified refrigeration engineer (REFCOM or equivalent).

What you might notice

What owners and engineers report

1 owner and engineer report mentions this.

  • Keeps stopping / cutting out on the Zeno A-Series air source heat pump (R32) AS01-R32/AS02-R32/AS03-R32: 1 report

Sources

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

Reviewed: 23 September 2026