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!
K3 rads and ASHPs
As part of the recent ASHP installation (discussed in another topic), most of the old K2 (double convector) rads were replaced with K3 (triple convector) rads, to make best use of the limited wall space in a cottage with relatively small rooms. I've noticed a number of them (perhaps all of them at some time or other) don't have the front panel heat up much, if at all, while the rear and middle panels do. This probably isn't helped by the fact K3s appear to be K2s with a third panel welded on in front, so the flow and return connections sit between the rear and mid panel, but I wondered whether this also caused by the relatively low ASHP flow temps, there just isn't enough delta T to get the whole rad hot. The rads are on their own secondary circuit, and the circulating pump Grundfos UPM3 AUTO is currently on its maximum constant pressure setting, and the rads are currently about 80-90% balanced, just got final tweaking to do. Has anyone else had a similar experience, and if so did you manage to improve it? It seems a pity to have all that potential output, but not use one third of it.
Midea 14kW (for now...) ASHP heating both building and DHW
- 27 Forums
- 2,808 Topics
- 66.3 K Posts
- 3,441 Online
- 7,211 Members
Join Us!
Installer Finder
Degrees of Separation
Latest Posts
-
RE: The Changing Jet Stream Could Challenge UK Air Source Heat Pumps
@susannasaunders I agree with @jamespa, I think that yo...
By Rob of York , 1 hour ago
-
Boiler Upgrade Scheme funding reduced by circa £750 million in 2026 budget
The funding for the BUS grant appears to have been subj...
By Rob of York , 2 hours ago
-
Hi, I had Marvel Heating install a heat pum...
By davidnolan22 , 3 hours ago
-
RE: Vaillant ecoTEC Plus - Flow Temp and Set Up
JamesPa The chart explains well how the heat curve an...
By trebor12345 , 5 hours ago
-
RE: Free app: run the immersion / heat pump from Growatt battery & solar surplus – no Home Assistant
Please bear in mind, everyone, that in order to use thi...
By Majordennisbloodnok , 1 day ago
-
RE: The good, the bad and the not that great – my heat pump installation
@burtis Thanks for posting this and Im so pleased you ...
By JamesPa , 1 day ago
-
RE: I need help with Ecodan ASHP
@f1p It turns out there have been a solar panel install...
By Andris , 2 days ago
-
RE: 15kw pump for 225m2 1990's house - over kill?
@seaviews your installer would be right to say that the...
By GrahamF , 2 days ago
-
RE: Tradespeople on Their Phones: What’s Acceptable When They’re Working in Your Home?
Actually, that's a very important point. I've only ev...
By Majordennisbloodnok , 2 days ago
-
RE: Aerotherm and weather compensation
These are likely inked. The basic explanation is tha...
By JamesPa , 2 days ago
-
RE: Electrical works for air to air heat pump
agree with above. I have not had extra costs added wh...
By Batpred , 2 days ago
-
Good to hear that you found a solution. Absolutely a...
By Batpred , 2 days ago
-
RE: Are there any comparisons of DHW heat stores around?
@sarahemmm I have done things the opposite way round I ...
By Toodles , 3 days ago
-
RE: How will removing the standing charge on gas bills benefit heat pumps?
The BUS grant funding for 2026/27 will run out at the c...
By Rob of York , 4 days ago




