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Radiator flow and return temps with my ASHP
Don't worry too much about deltaT across radiator flow/return - my system runs at about 2-4 degrees. House is nice and warm, everything works...
Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.
My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.
Hi @derek-m yes I had no idea how that thing worked and I'm glad I now do! Our auxiliary pump (Evosta 2) is set on speed 1 (lowest). Should tightening the lockshields encourage a lower flow rate and increase the delta T across the radiators? I'm led to believe that in a system using such manifolds I don't have to worry about upsetting balancing and the like.
Thanks @hughf - our replies crossed in the post it seems. Yes, I may be spending too much time worrying about the delta t across the radiators as we have a fairly constant and comfortable temp in the rooms. Sometimes spending too much time reading stuff on the internet may lead you to believe your system has all kinds of imagined illnesses... 😆
Posted by: @marzipan71Hi @derek-m yes I had no idea how that thing worked and I'm glad I now do! Our auxiliary pump (Evosta 2) is set on speed 1 (lowest). Should tightening the lockshields encourage a lower flow rate and increase the delta T across the radiators? I'm led to believe that in a system using such manifolds I don't have to worry about upsetting balancing and the like.
The lockshield valves should be adjusted to balance room temperatures. As Hugh has suggested, don't worry about the DT provided that your home is warm. A lower DT should actually mean that your heat pump can operate at a lower LWT, which should improve efficiency.
@derek-m And much ‘fun’ may be had with setting lock shield valves to best advantage; I’ve found that much joyful tweaking may be enjoyed over time. Now I have the Homely smart controller micro-managing the whole system for me, I have set the radiator in the room with the ‘node’ (temperature sensor) for a good amount of heat in that room. After I had established a setting that didn’t throttle the whole system back due to that room heating up and causing the Homely to reduce the heat pump output whilst other rooms were still cool, I then tweaked various radiators to even out the heat requirement and now have all rooms equally warm. This setting may be slightly different to the lock shield settings I had before Homely days as then I had the Heatmiser NeoStat set above maximum temperature requirement and used the Daikin MMI settings with LWT and WC which did a fair job most of the time. I think the tweaking days are more or less over now and I can put the caps back on the lock shield valves… Regards, Toodles.
Toodles, heats his home with cold draughts and cooks food with magnets.
@toodles I'm definitely going to look into Homely in 2024 for my Daikin Altherma HT. My system always seems to be an outlier for some reason and I'll have to discuss with them whether it really is supported, but it looks very interesting.
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