Forums

Forums
Renewable Heating
Air Source Heat Pum...
Is it crucial to ge...
 
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. 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!

Is it crucial to get flow temperatures with heat pumps right?

 
Page 7 / 8
Air Source Heat Pumps (ASHPs)
Last Post by Alfapat 1 year ago
93 Posts
7 Users
1 Reactions
12 K Views
RSS
Toodles
 Toodles
(@toodles)
Famed Member Contributor
Joined: 3 years ago
Posts: 2639
12/01/2025 5:38 pm  

@alfapat The radiator / emitter that takes the longest to heat up will be the one LSV that remains fully open and all others will then end up somewhere between almost fully open and almost closed (though in practice, this means just a half turn or so from closed due to the nature of the valve’s design in many cases) The aim is to have as low a resistance to flow as can be achieved - hence one LSV being fully open - all others are compared to this in the end. By the way, it is quite possible that the radiator / emitter right at the end of the pipe run will be fed by the water that has released some heat by the time it gets to there and might well be the LSV that remains fully open BUT … this is not a given, an over or undersized  radiator / emitter elsewhere might require more / less throttling to achieve a balance! My wife occasionally challenges me when I am walking around the house with a radiator key! Not so much  a science but an art! Regards, Toodles


Toodles, heats his home with cold draughts and cooks food with magnets.


   
ReplyQuote
 Alfapat
(@alfapat)
Estimable Member Member
Joined: 3 years ago
Posts: 187
Topic starter 12/01/2025 5:39 pm  

@jamespa All Rads sized.



   
ReplyQuote
JamesPa
 JamesPa
(@jamespa)
Illustrious Member Moderator
Joined: 3 years ago
Posts: 4475
12/01/2025 7:48 pm  

Posted by: @alfapat
↑

@jamespa All Rads sized.

... in theory!

If they are all (close to ) perfectly sized then adjusting setting them up for consistent deltaT across the radiator is another way to balance.  Some plumbers do this by 'feel' I am told. 

Its still the same laborious and iterative task of adjusting the LSVs though.  We definitely need a variant of a TRV that does this automatically.  It should never (or almost never) shut down completely and should work out how much to throttle by over a period of a few days.  The hardware exists, it needs the right firmware, not sure whether all the TRVs in the house would have to communicate to make it work or whether they could use some sort of random delay protocol (a bit like ethernet).  Essentially Adia are creating a system to do this with a central controller (which communicates with the heat pump - ideal but potentially limiting as they dont support all heat pumps); doubtless they have some future development ideas in mind.

 


This post was modified 1 year ago 2 times by JamesPa

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



 Alfapat
(@alfapat)
Estimable Member Member
Joined: 3 years ago
Posts: 187
Topic starter 12/01/2025 11:14 pm  

@jamespa If only! 
Hindsight is great , but I was presented with the design 8 yrs ago , so I can only hope that they do the job , most of the time when the temperatures are there when required , they seem to do the job. 
It’s the cost of doing it !



   
ReplyQuote
 Alfapat
(@alfapat)
Estimable Member Member
Joined: 3 years ago
Posts: 187
Topic starter 13/01/2025 2:37 pm  

Still at it here , correct me if I am wrong , I am still adjusting lockshields and happen to put a simple temp probe on ingoing /outgoing pipes at the Rads and the temperature at the TRV is higher than at the lockshield is this right. 😕 Surely the flow is lockshield to TRV which incedently is fully open



   
ReplyQuote
bontwoody
 bontwoody
(@bontwoody)
Noble Member Contributor
Joined: 4 years ago
Posts: 1003
13/01/2025 2:46 pm  

@alfapat I think modern TRVs can be fitted on either side. The lock shield will restrict flow whichever side it is sited


House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60


   
ReplyQuote



 Alfapat
(@alfapat)
Estimable Member Member
Joined: 3 years ago
Posts: 187
Topic starter 13/01/2025 2:53 pm  

@bontwoody Thanks , In thought it was a dumb question but hey ho you learn something new every day. Slowly getting round to turning lockshields down.



   
ReplyQuote
bontwoody
 bontwoody
(@bontwoody)
Noble Member Contributor
Joined: 4 years ago
Posts: 1003
13/01/2025 3:43 pm  

@alfapat There is no such thing as a dumb question, just a dumb answer 🙂


House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60


   
ReplyQuote
Toodles
 Toodles
(@toodles)
Famed Member Contributor
Joined: 3 years ago
Posts: 2639
13/01/2025 4:48 pm  

@alfapat One would expect the flow to be into the emitter from the TRV but, my installers informed me that the modern valve bodies are so made that direction of flow is no longer important. In terms of the LSV, it is restricting the flow, regardless of whether it is in the flow or return run. Regards, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
ReplyQuote



Toodles
 Toodles
(@toodles)
Famed Member Contributor
Joined: 3 years ago
Posts: 2639
13/01/2025 4:50 pm  

@bontwoody We all learn summat every day - it is just that some of us (me in particular) forget to remember it!😉 Regrets, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
👍
1
ReplyQuote
 Alfapat
(@alfapat)
Estimable Member Member
Joined: 3 years ago
Posts: 187
Topic starter 13/01/2025 5:21 pm  

Posted by: @toodles
↑

@bontwoody We all learn summat every day - it is just that some of us (me in particular) forget to remember it!😉 Regrets, Toodles.

🤣

 



   
ReplyQuote
JamesPa
 JamesPa
(@jamespa)
Illustrious Member Moderator
Joined: 3 years ago
Posts: 4475
13/01/2025 10:24 pm  

The bodies of TRVs usually have an arrow on them.  If it can operate bidirectionally it will be a bidirectional arrow!


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



Page 7 / 8
Forum Jump:
  Previous Topic
Next Topic  

Currently viewing this topic 1 guest.



Share:

Join Us!

Worth Watching

Latest Posts

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