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Heat pumps · Error codes · Warmflow
F11Warmflow

F11 on a Warmflow heat pump: DSP Communication Error

Short answer

On a Warmflow heat pump, F11 means: DSP Communication Error. 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: DSP Communication Error.

Part involved: controller/PCB communication.

Likely causes:

  • There is a communication error between the DSP and the inverter.

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 controller display is lit and showing the code.

What the engineer will check

  • Check the wiring and connection between the DSP and the inverter.

Who to ask for: heat pump controls / electrical.

Certification: Electrical competence (Part P / qualified electrician) for work inside control panels.

What you might notice

What owners and engineers report

2 owner and engineer reports mention this.

  • Controller / thermostat problem on the Zeno R290 air source heat pump AS01-R290/AS02-R290/AS03-R290: 1 report
  • Controller / thermostat problem 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