Renewable Heating Hub Heat Pump Forums

Search with Wattson
Forums
Renewable Heating
Air Source Heat Pum...
Daikin Altherma 3 H...
 
Notifications
Clear all

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!

Daikin Altherma 3 H HT - Freeze Prevention Threshold

 
Air Source Heat Pumps (ASHPs)
Last Post by RICHARDF5033 7 months ago
1 Posts
1 Users
0 Reactions
793 Views
RSS
 RICHARDF5033
(@richardf5033)
New Member Member
Joined: 7 months ago
Posts: 1
Topic starter 18/02/2026 1:34 pm   [#2835]

Hi. We have an Altherma 3 HT (18kW I think) which, now we've completed a load of tweaking, gives a SCOP of around 3.6. It is used in a single storey barn conversion with a lot of vaulted ceilings (not great), and underfloor heating system. Because it is single storey, it is 'long and low'. As a result, when the system was installed 14 years ago, it was fitted with pipe freeze prevention valves rather than adding glycol (I guess over concerns of the glycol reducing the heat-carrying capability of the water over the 45m run to the farthest room). This causes a problem on cold but sunny winter days. Because the house benefits from a lot of solar gain, the stats will frequently switch off and the heatpump stops. But because the pump isn't running and the water in the system doesn't have glycol added, the system protects the external pipes from freezing by taking heat from the hot water tank causing either a huge drop in water temp, or excess electricity usage to keep reheating the water. What troubles me most, is that this Pipe Freeze Prevention cycle kicks in when the outside temperature drops to 6.9 degrees centigrade. This seems excessively high and dictates that any sunny day from late autumn to late spring means we have to have heating running whether the house needs it or not. My question therefore is; is 7 degrees the correct threshold? Our engineer is stumped as he has found a setting which "appears to be" the threshold for the freeze protection, currently set at 7, but on the Daikin app shows as a default of 3. (It is setting 407). The problem is, it is the only setting that doesn't have a title/explanation within the app! Can anyone confirm what level the Pipe Freeze Prevention threshold should be set at by default and if 407 is the appropriate setting please? Cheers.



   
Quote
Topic Tags
Altherma Freeze Glycol
Forum Jump:
  Previous Topic
Next Topic  
Related Topics
Topic Tags:  Altherma (1) , Freeze (1) , Glycol (2) ,
Share:

SPONSORS

Join Us!

Installer Finder

Degrees of Separation

Latest Posts

SPONSORS

Click to access the login or register cheese
Protected By
Shield Security PRO