Ecodan control failure

[Parkcollege]

Hi Thank you for letting me join the forum. I have a problem with a Renewable heating system. The control panel is an FTC5 PAC IF063B-E
 

there is a ASHP for under floor and HW. We have an immersion for hot water too. 
 

recently the hot water has stopped working. The immersion doesn’t come on either. I’ve hard wired the the immersion and it does work so the problem is somewhere in the control. 
 

looking at the thermistors all give sensible temperatures other than TH1A which says -39. 
 

when using manual control all pumps work but they don’t come on otherwise using the timer. 
 

any suggestions of where to look to solve the problem. 

Edited August 14, 2021 by Parkcollege

[Conor]

Have you spoken the the supplier or Mitsubishi? I've head they are good for support (one reason why they are so popular)

[Parkcollege]

Thank you- I did and they replied very quickly which was great but all they suggested was to turn it off and on. Which surprisingly I’d already tried, several times, but to no avail. Hopefully they’ll be able to give some more helpful Suggestions

[Temp]

I found the manual online here but cant find "TH1A" mentioned in it.  Nothing obvious in the Trouble shooting section.

 

https://www.manualslib.com/products/Mitsubishi-Electric-Pac-If063b-E-8788433.html

 

 

[Parkcollege]

1 hour ago, Temp said:

I found the manual online here but cant find "TH1A" mentioned in it.  Nothing obvious in the Trouble shooting section.

 

https://www.manualslib.com/products/Mitsubishi-Electric-Pac-If063b-E-8788433.html

 

 

Thank you - yes I found that too and couldn’t seem to find much of help in there. The LEDs on the pcb seem to be normal according to the manual.