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Mitsubishi Ecodan fault E1

Main remote controller control board failure

Heat pump

What it means

Displayed if main remote controller cannot access its non volatile (non power dependent) memory.

Likely causes

  1. Fault with the main remote controller circuit board
  2. Outdoor unit abnormal stop triggers automatic backup operation

Where to start

  1. Check OUT1 (Water circulation pump 1, Space heating/cooling & DHW) at TBO.1 1-2, connector CNP1.
  2. Check OUT2 (Water circulation pump 2, Zone1) at TBO.1 3-4.
  3. Check OUT3 (Water circulation pump 3, Zone2 / 2-way valve 2b output) at TBO.1 5-6.

The full answer, free

  • 39 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 51), 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.

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