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Mitsubishi Ecodan fault 3

Main screen appears then disappears after pressing ON button

Heat pump

What it means

The main screen appears briefly when ON is pressed but disappears within a second; this is normal operation while the indoor unit applies updated settings made in the service menu.

Likely causes

  1. 2 or more main remote controllers have been connected to the FTC
  2. Fault with main remote controller transmission/receiving circuit board
  3. Electrical noise causes interference with transmission/reception of data for main remote controller
  4. System is applying updated settings made in the service menu

Where to start

  1. Only connect 1 main remote controller to 1 FTC indoor unit board
  2. Turn the power to the indoor unit OFF and then ON
  3. Power to both the indoor unit and outdoor units should be switched OFF then ON

The full answer, free

  • 19 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 54), 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