Joining the Renewable Heating Hub forums is completely free and only takes a minute. By registering you’ll be able to ask questions, join discussions, follow topics you’re interested in, bookmark useful threads and receive notifications when someone replies. Non-registered members also do not have access to our AI features. When choosing your username, please note that it cannot be changed later, so we recommend avoiding brand or product names. Before registering, please take a moment to read the Forum Rules & Terms of Use so we can keep the community helpful, respectful and informative for everyone. Thanks for joining!
Vaillant Arotherm Plus PCB Failure
Hello all
I have a 5kw Arotherm Plus ASHP which was commissioned around 18 months ago however unused for around 9 months.
On restarting the system the ASHP was showing connected but wouldn't start then heat was requested (DHW or Heating) and after a few hours F.1117 Compressor Failure was shown.
Investigating further its evident that the 240vAC neutral on the PCB has failed - looks like it has overheated/melted.
Has anyone had similar issues and if so do you know the root cause? I've temporarily repaired the board which now means the ASHP is functional so I know this is the problem but before I replace the board I'd like to know why it happened and how to try and prevent it happening again!
I'll try and contact Vaillant directly also.
Thanks in advance for any advice!!
Hi, I have the same problem. Same place, what was the cause of the problem?
thx for the reply,
wim
Your original post must have fallen into the 'black hole' that appears to exist in the website from time to time.
Looking at the photos I suspect that the cause may have been condensation, possibly due to the heat pump not being used for 9 months.
@derek-m , @wimdeboysere - I've no idea what caused it - could see how potentially was condensation, didn't open the unit up prior to restarting it.
A new board is in and all has been fine since!
Posted by: @derek-mYour original post must have fallen into the 'black hole' that appears to exist in the website from time to time.
Looking at the photos I suspect that the cause may have been condensation, possibly due to the heat pump not being used for 9 months.
It is difficult to tell from the photo's, but PCB's for outdoor use should be coated with a waterproof lacquer.
I think the main board on the unistor is also Broken, screen shows connection failure and i cant measure power on the bus connection, Room thermostat is also dead.So the best thing tot do is put in a new main also of does it get power from the (dead)heatpump outside?
@pdfreeman did you have to pay for the replacement and did Vaillant offer any information on what may have caused this?
🔥 Britain’s Heat Pump Shitshow
How Installing a Heating System Became a National Nervous Breakdown
Free UK shipping.
Rewritten and updated for 2027
📘 From Zero to Heat Pump Hero
🛠️ Bodge Buster
New to heat pumps?
Take the Heat Pump Fundamentals course and use INTRO50 at checkout for 50% off.
@wimdeboysere did you have your system installed after pdfreeman’s and how long has yours been installed?
Have you raised it with Vaillant?
🔥 Britain’s Heat Pump Shitshow
How Installing a Heating System Became a National Nervous Breakdown
Free UK shipping.
Rewritten and updated for 2027
📘 From Zero to Heat Pump Hero
🛠️ Bodge Buster
New to heat pumps?
Take the Heat Pump Fundamentals course and use INTRO50 at checkout for 50% off.
Did the fried slug on the left have anything to do with the failure or was it collateral damage!
-
Heat pump done right first time? Installation in Kent.
3 months ago
-
Vaillant arotherm plus heat pump frost protection
4 months ago
-
ECO4, ECO3, ECO2, ECO1, HUS, BUS, GBIS Dedicated Support and Advice
5 months ago
-
Vaillant aroTHERM plus not level or flat - what base is best under an external unit?
2 years ago
-
Vaillant Arotherm monobloc error f.788 - ASHP is not working!
2 years ago
Currently viewing this topic 1 guest.
- 27 Forums
- 2,763 Topics
- 65.1 K Posts
- 1,841 Online
- 7,169 Members
Join Us!
Installer Finder
Degrees of Separation
Latest Posts
-
Vaillant Arotherm Plus 7KW need a service on it
looking for a service to be done on my heat pump, im ba...
By AdamK , 36 minutes ago
-
RE: Two heating zones to one zone
@transparent Many thanks. The garage is fairly well ...
By Profzarkov , 2 hours ago
-
RE: Vaillant Aurotherm - Heater Wire Position
Ah, good point. I need to check if this was installed i...
By Batpred , 8 hours ago
-
RE: Adventures in heat loss calculations
Posted by: @jamespa At this point its probably worth...
By Rob of York , 10 hours ago
-
@batpred thanks for getting a copy. Appreciate the supp...
By Mars , 19 hours ago
-
RE: Tell us about your Solar (PV) setup
We have a 6.56kW solar PV system (16x 410W panels) inst...
By Rob of York , 1 day ago
-
RE: Where heat loss surveys seem to go against practical reality
@cathoderay @jamespa I've managed to get some nice re...
By Rob of York , 2 days ago
-
RE: 7kW EV Charger Options Advice
Doh, not sure that I was thinking straight there, less ...
By Rusty , 2 days ago
-
RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S
I’m really liking reading through this thread and the r...
By Judith , 2 days ago
-
Thank you @trebor12345
By rgabor , 2 days ago
-
Panasonic Free Multi Z and Etherea Internal units.
My prospective installers have suggested the Panasonic ...
By Toodles , 3 days ago
-
RE: Next steps on my ASHP journey: Radiators and Pipework
Great. You just need to find a way of cranking up your...
By JamesPa , 3 days ago
-
RE: Heat Pumps Without Grants: Would You Have Installed One & Will You Now?
We had two heat pumps installed without Govt funding. H...
By Rob of York , 3 days ago
-
My Adapt is finally installed and running! Almost a yea...
By tomasmcguinness , 3 days ago








