Hey all, nearly had our ASHP for about 10 months now but first time going into a winter with it.
I have been running inactive for most part of the year but decided to run active for a little bit, Micks article is great in explaining how it all works.
The only question I have about active mode, I understand if pure WC is not quite enough then it increases the flow temperature slightly to compensate but does active work in reverse eg solar gain or other room temperature external influences then does it reduce the flow temperature.
I am undecided if to stick with active as I know inactive is the best for COP/SCOP.
They run through the kitchen ceiling as we were renovating it at the same time. They are insulated, but clipped with those white nailed to joist type clips, plumber didn’t see them as an issue as other plumbers have used them in the past. My install was part my plumber part a heat geek company., so they are blaming Vaillant each other etc. if I had know they would be noisy I would have run them round the outside of the house. Think the heat pump installers and YouTubers need to point this out if installing the Vaillant 7kw. Also the pump is on auto.
My installer came back to fix the pH balance on the water, and I noticed the flow rate changed from a sawtooth to a flat flow rate. Looking at other HPs they have a sawtooth as well. I use Havenwise to optimise the heat pump, but given the timing, I don’t think that has changed. The house is nice and warm, but is it something I should be worried about? The second picture is yesterday, where I have an air in the system problem. There are also these spike up and down on the flow.
I doubt you’d see much COP difference between active and inactive.
Inactive might be able to knock a couple of degrees off the flow temp is too high (solar gain etc), saving a bit, but i think it would be negligible. the reason i suggest active over inactive is primarily comfort.
Unless you have turned your flow rate to the absolute minimum via reducing the max. rem head setting to squeeze the last percent of performance out of your oversized heat pump as I described here. In this case, flow rate stays flat all the time. This is with Max. rem. head set to 350 mbar for me, which is barely above the stalling limit.
Use Expanded mode so the pump turns off when heat isn’t needed. If it does affect your efficiency, it will only be for the better. It will certainly cut your energy consumption.
I think you can schedule the circulation pump to stop running for a period via the SensoComfort. Mine is off from around midnight to 7am I think. I haven’t paid much attention to it tbh.
Obviously its not going to be possible to switch off the circulation pump without somehow switching off the heating as this would leave nowhere for the energy to go, however
I think that:
If you schedule heating off altogether then the circulation pump will switch off.
If you operate in expanded mode and schedule a setback, the heating will switch off entirely until the house cools to the setback temperature, which will switch off the circulation pump.
Note that doing either of these may reduce your efficiency and increase cost, depending on your house and settings.
@Zarch I have solar tubes on my house roof, which is linked into both coils in its tank. We aren’t huge hot water users either, so I decided that for the few months of they year that the immersion is needed, and with low night rate electricity, it made sense to leave DHW out of my setup and leave the Vaillant to space heating only.
It seems that @Andre_K has capably added to your bible of knowledge
I just hope that end users will appreciate the time and effort that you have put into these articles. They certainly helped me when I self installed mine a year ago
