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Mitsubishi Ecodan F8 error

 
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Air Source Heat Pumps (ASHPs)
Last Post by JamesPa 10 months ago
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Mars
 Mars
(@editor)
Illustrious Member Admin
Joined: 6 years ago
Posts: 4809
08/10/2025 10:54 pm  

Posted by: @ashp-bobba
↑

Just to add to the F8 non existing code, in the book is all of the blinking codes and could be worth double checking it not trying to display a P8 which could look like a F8

I absolutely love this. This is the quintessential heat pump user experience.

Mitsi spent millions on the vapour compression cycle, only to delegate diagnostics to a single LED trying to communicate the difference between a Fault () and Performance issue () via blinking cadence that may or may not exist. I love it. It's less an error code and more a Rorschach test. 🤯

 


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JamesPa
 JamesPa
(@jamespa)
Illustrious Member Moderator
Joined: 3 years ago
Posts: 5269
09/10/2025 9:52 am  

Better than an early Windows/DOS error 'Faulty keyboard or keyboard not present, press F1 to continue'.  This persisted for a couple of decades at least.

There may actually be some sense in the flashing led thing, it probably works even if the circuit that is responsible for the display isn't working thus proviving a fall back basic diagnostic.  Computers emit a series of beeps on startup, the pattern of which depends on faults, for this precise reason.  

 


This post was modified 10 months ago by Mars

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.


   
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