Forums

Forums
Renewable Heating
Air Source Heat Pum...
Vaillant aroTherm n...
 
Notifications
Clear all

Vaillant aroTherm not heating with many faults

 
Air Source Heat Pumps (ASHPs)
Last Post by JamesPa 9 hours ago
2 Posts
2 Users
0 Reactions
68 Views
RSS
 Anon67
(@anon67)
New Member Member
Joined: 11 hours ago
Posts: 1
Topic starter 10/01/2026 9:01 pm  

I have a 3 year old 10kW vaillant aroTherm heat pump connected to dhw and ufh.

The heat pump kicks in on demand for hot water but when it comes to heating it faults, getting a mixture of faults 

F.732 Compressor outlet temperature too high

F. 733 Evaporation temperature too low

F. 0521 Outdoor temperature sensor signal invalid

Does anyone have any ideas how I can get the heating back on even temporary? Until I can get someone to look at it on Monday. 

I tried looking through the menu but there doesn't seem to be any option to force heat. 


This topic was modified 11 hours ago by Mars

   
Quote
 JamesPa
(@jamespa)
Illustrious Member Moderator
Joined: 3 years ago
Posts: 3904
10/01/2026 11:01 pm  

Posted by: @anon67
↑

I have a 3 year old 10kW vaillant aroTherm heat pump connected to dhw and ufh.

The heat pump kicks in on demand for hot water but when it comes to heating it faults, getting a mixture of faults 

F.732 Compressor outlet temperature too high

F. 733 Evaporation temperature too low

F. 0521 Outdoor temperature sensor signal invalid

Does anyone have any ideas how I can get the heating back on even temporary? Until I can get someone to look at it on Monday. 

I tried looking through the menu but there doesn't seem to be any option to force heat. 

When I had a series of apparently unrelated faults my installer turned up, checked the flow rate using the test menu, and cleaned the filters (two - a mag filter and a gauze filter immediately behind the unit).  Fixed the problem.,  He told me that 90% of call outs are that.  None of the apparently unrelated faults said anything about flow rate!

That said the fact it heats hot water suggests its not filters so...

If you go into live monitor on the HPAI and look at the first screen it initially shows --.  Until my installer showed what to do at this point I have always 'clicked past'.  But if you wait a few seconds on that screen it gives you a stream of consciousness about what the heat pump is doing.  That may reveal something.

 

 


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.


   
ReplyQuote
Forum Jump:
  Previous Topic

Recently viewed by users: Anon67 58 minutes ago.



Share:

Join Us!

Worth Watching

Latest Posts

Click to access the login or register cheese
x Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
ShieldPRO →