Rads warm when heating not on but ASHPs heating hot water
Hi All
Some of our rads are warm when the ASHPs are heating our hot water. The 3 port valve which controls where to send flow from the ASHPs is set to the hot water cylinder only. when not set to heat water, the 3 port valve sends water from the ASHPs to the rad and UFH circuits where that is ocntroledd by 2 x 2 port valves according to heat demand. The 2 port valve in the loft which opens and closes the radiator circuit is closed ( controlled by room stat which is not calling for heat ). The UFH circuit 2 port valve is closed. No sign of any warmth in the UFH system on the Ground floor.
Could the 3 port valve be leaking some hot water to the rad circuit?
Or more likely, the 2 port in the loft is allowing hot water from the ASHP primary circuit to leak through into some of the rads?
Any ideas gratefully received. Hope the above makes sense.
Cheers
Alan
It’s a bit left of field but could your 3 port valve be a mid position three port valve? Does the CH side of it get hot when DHW is on?
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
Is it the orange Belimo 3-way valve?
Get a copy of The Ultimate Guide to Heat Pumps
Subscribe and follow our Homeowners’ Q&A heat pump podcast
Posted by: @alanbHi All
Some of our rads are warm when the ASHPs are heating our hot water. The 3 port valve which controls where to send flow from the ASHPs is set to the hot water cylinder only. when not set to heat water, the 3 port valve sends water from the ASHPs to the rad and UFH circuits where that is ocntroledd by 2 x 2 port valves according to heat demand. The 2 port valve in the loft which opens and closes the radiator circuit is closed ( controlled by room stat which is not calling for heat ). The UFH circuit 2 port valve is closed. No sign of any warmth in the UFH system on the Ground floor.
Could the 3 port valve be leaking some hot water to the rad circuit?
Or more likely, the 2 port in the loft is allowing hot water from the ASHP primary circuit to leak through into some of the rads?
Any ideas gratefully received. Hope the above makes sense.
Cheers
Alan
How warm are the radiators and do they remain warm? Are the radiators warm before the system changes to DHW heating?
What is the temperature setting of the thermostat for the radiators?
- 26 Forums
- 2,255 Topics
- 50.3 K Posts
- 310 Online
- 5,918 Members
Join Us!
Podcast Picks
Latest Posts
- 
                        RE: Daikin Altherma 3 / HomeAssistant I don’t have a Shelly EM on my heatpump, so only see th... By DCSH , 3 hours ago 
- 
                        RE: Help me keep the faith with my air source heat pump installation have you got an ebus adapter on yours? By AdamK , 3 hours ago 
- 
                        RE: When will fusion be producing energy? From the time I was a physics undergraduate it’s been 2... By Judith , 4 hours ago 
- 
                        RE: Is it mad to think there should be a minimum SCOP for UK heat pump installs? Sadly I think it is mad. If the BUS is not granted for ... By Judith , 4 hours ago 
- 
                          RE: Who has a V2G EV installation Perfect, @agentgeorge. I’m always up for some edificati... By Majordennisbloodnok , 4 hours ago 
- 
                        RE: My experience with 3 heat pump surveys: Heat Geek, British Gas & Octopus Yes but... The evidence is that many heat loss survey... By JamesPa , 5 hours ago 
- 
                          What Adam Chapman gets up to in his Spare Time. Ok, so this just appeared on YouTube (don’t blame me th... By Toodles , 5 hours ago 
- 
                          RE: Radiator Sizing Dilemma: Vertical vs Type 33 for Low-Temperature Heat Pump Systems That's my main concern too. On top of that, I ... By DREI , 7 hours ago 
- 
                        RE: Are We Sleepwalking Into Another Race to the Bottom? Also it embeds a complex system, almost taking the home... By JamesPa , 7 hours ago 
- 
                        RE: Grant 13kW Aerona3 - issues getting zones to temp Thanks, patience is something I’m trying to ma... By Crimson , 9 hours ago 
- 
                        RE: Solar Power Output – Let’s Compare Generation Figures 2025 - now a record year of Solar PV Generation. Octobe... By AllyFish , 12 hours ago 
- 
                          RE: Midea ASHP – how to set weather compensation @pash44pump - AI may have its uses (and I sort of allow... By cathodeRay , 13 hours ago 
- 
                        RE: Mitsubishi Ecodan R290 10kW performance Totally agree that any system is reliant on the ability... By Sheriff Fatman , 14 hours ago 
- 
                        British Gas Heat Pump Installation Complaint In 2024, my wife and I thought that we would try to do ... By BGNO , 15 hours ago 
- 
                          Erm... no we can't! The issue first raised by the OP ... By Transparent , 16 hours ago 
- 
                        RE: Testing new controls/monitoring for Midea Clone ASHP Thx, but Sven did the hardware development. My role (as... By Mosibi , 1 day ago 
- 
                        RE: PV Panels on roof in Conservation Area @majordennisbloodnok Fnaargh, I was thinking about try... By colinc , 1 day ago 
- 
                        RE: Electricity price predictions @jamespa Ah, you mean MPs that have not pro... By Batpred , 1 day ago 
- 
                        RE: Buying large amp bidirectional RCD and RCBO Exactly @transparent , this type of RCBOs are not easil... By Batpred , 1 day ago 



 
                        

 
                                 
                                 
                                 
                                 
                                
