Hello,
Just going through fitting our ufh and heat pump. Would ideally run the downstairs as an open loop design for maximum efficiency.
In respect of the ufh manifold, is it better to have
A) no actuators at all, and just run it that way permanently circulating with the heat pump controlling via weather compensation
B) use normally open actuators with the above? (So you do have that control point)
We have UFH down and upstairs, each on their own manifold.
We have 4 towel rads on a separate loop off the main feed to the UFH manifolds, and a 1400 X 600 triple rad in an annexe room also off the main feed.
All are âopenâ / always on and driven by the ASHP water pump.
Balancing is done via the UFH manifold flow adjuster valves and the towel rad balancer taps.
The triple rad is fully open. I fitted this after calculating the heat loss of the room and the required output for that at Delta T of 10°C (normal boiler rad would be 50°C).
That annex room is the perfect temperature for us.
I think most efficient is if you can go open and balance.
Hi Steve, just a clarification on room thermostats.
Under option (A) you appear to have a single thermostat.
Under option (B) you have one or more room thermostats, but it is unclear to me how you intend to âopenâ the actuators if it is linked to room thermostats.
In our house, I opted for a fully open system, all UFH, a single hallway thermostat, no actuator controls ( but achieved room balancing manually via the manifold flow valves). The water is circulated via the heat pump itself. The performance is very good.
Provided you have a 13 amp socket near the manifold you can add activator and wireless thermostat if you prove you need them. Everything fully open loop, balanced, and pipe spacing chosen based on relative heatlose of rooms will normally give best results.
However you may find some rooms need temperature limiting due to thermal gain or a study that is sometimes used as a bedroom.
Answer to the above needs way more information, as it will vary depending on house, heat loss and floor buildup. A low heat loss house will have flow temperature and actual floor temperature very close to actual room temperature, so having a thermostat adds zero value, as floor will self modulate. Example if floor surface temp is 22 degs and room is 22 or warmer the floor can no longer pass energy to the room. So then option B is sensible. However if your house looses plenty of heat you may have higher flow temperature and floor temperature so self modulation doesnât occur, now you may need some room temperature regulation.
However add the thermostat you decrease system volume available, reduce system flow and get towards buffer etc.
Our flow temp needs are so low that I have to run a single thermostat and almost batch charge the floor for most of the winter. Min flow set at 26 and max flow 28.
Target flow temp is 33C, heat loss of ~4.12kw.
What floor area is the UFH over and is that providing the full heat loss?
What depth are the pipes from surface. Are they embedded in screed