Mitsubishi Ecodan fault 10

Temperature of DHW tank water dropped

Heat pump

What it means

Water in the DHW tank reheats too frequently due to significant temperature drop, often caused by water leakage, loose insulation, 3-way valve failure, or incorrect water pump speed setting.

Likely causes

  1. Water leakage in the pipes that connect to the DHW tank
  2. Water pump (sanitary circuit) speed setting failure

Where to start

  1. Reoccurring problem with error code Displayed: Use table 10-4 'Self diagnosis and action' to identify fault and correct
  2. Reoccurring problem with error code Not Displayed: Use table 10-5 'Troubleshooting by inferior phenomena' to identify fault and correct
  3. Non reoccurring problem, error Logged: Check temporary causes of defects such as operation of safety devices on refrigerant/water circuit including compressor, poor wiring, electrical noise etc; re-check symptom and installation environment, refrigerant amount (split systems only), weather conditions at time of fault

The full answer, free

  • 12 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 55), right under the answer

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.

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