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Mitsubishi Ecodan fault 26

Water circulation pump runs for a short time unexpectedly

Heat pump

What it means

Water circulation pump periodically runs for a short time as part of a routine jam prevention mechanism to inhibit scale build-up.

Likely causes

  1. Water circulation pump jam prevention mechanism (routine) to inhibit the build-up of scale
  2. Immersion heater degradation causing earth leakage, triggering circuit breaker (heater always OFF)
  3. Water circulation pump wear leading to pump failure

Where to start

  1. Refer to outdoor unit manual for refrigerant models only (except EHPT20 series)
  2. Check condition of cables
  3. Check rating and fuse fitted on the electricity supply

The full answer, free

  • 21 more checks in order
  • The readings and component tests from the manual
  • How to put it right, step by step
  • The manual page for this fault (page 57), right under the answer
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Safety: Isolate the outdoor unit and any backup heater, and give the inverter capacitors time to discharge before you open the electrics. Anything on the refrigerant circuit needs F-gas certification.

From the Mitsubishi manual for the Ecodan. Check the model on the data plate before you order parts.

Other Mitsubishi Ecodan fault codes