Renewable Heating Hub Heat Pump Forums

Search with Wattson
Forums
Renewable Heating
Air Source Heat Pum...
New heat pump heati...
 
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!

New heat pump heating system underperforming in Italy... Advice needed!

 
Air Source Heat Pumps (ASHPs)
Last Post by robinlawrie 11 months ago
1 Posts
1 Users
0 Reactions
836 Views
RSS
 robinlawrie
(@robinlawrie)
New Member Member
Joined: 11 months ago
Posts: 1
Topic starter 19/08/2025 12:09 pm   [#2426]

hi all, first post! I've just renovated a house in southern italy and spent a fortune on a 20kw heat pump  system with two inverter fancoils, ducted to all rooms, for heating and cooling.  the house is large and not well insulated hence the large capacity of the system. 

the heat pumps (there are two, in master/slave config)  are 10kw Ferroli Omnia 3.2.   they are connected to a 150 litre buffer tank (i think thats  the correct term)   which then feeds the two fancoils which are situated above a false cieling in the main corridor. 

here is a link to the brochure of the heatpumps, for reference: 

having lived here for one winter, and most of a summer, i have been observing the system.   firstly, in winter it struggles to get the house over 18 degrees, and in summer (when its 37+ degrees outside) it struggles to cool it under 26 degrees.

the installer has said repeatedly that it needs to be left on 24h a day to achieve the desired performance.     this may well be true, however i have noticed a strange behaviour which is likely also contributing:

the control panel of the heatpumps reports the heat/cooling output of the two machines, and ive never seen the combined total go over 12kw in either heating or cooling mode.

usually it reports around 3-4kw for one machine and 5-6kw  for the other. 

the other day i checked it specifically after running for half an hour in cooling mode, with the water temperature set to 7 degrees (quite low for decent efficiency,  but im trying to get the house cool, and i have solar panels so free electricity during the day) 

water output temp reported from the pumps was 12 degrees and the return temperature was 16 degrees, this means to me that the buffer tank was not yet cooled down, hopefully eliminating the fancoils from the equation. 

main pump was outputting 5.2 kw, slave was 6.4 kw.  this is about as high as ive ever seen it. 

 what could be the cause?    

the installer is being slippery, saying "its normal the output will vary all the time"   "you are lucky, imagine the bills if it was running full tilt"   and "leave it running all day itll be fine" 

Once we have a decent battery system,  ill be more happy to leave it running when theres no sun, but currently,  leaving it on 24 hrs a day would absolutely massacre us on the bills, and thats without it running at the rated 20kw. 

besides, thats a different discussion. 


This topic was modified 11 months ago 2 times by Mars

   
Quote
Forum Jump:
  Previous Topic
Next Topic  
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