Dreadnaught

Interestingly Ovo is also offering a trial* of an add-on that incentives users to shift consumption away from the peak period (4pm to 7pm). It's a monthly refund for such usage shifting and can be taken along with the "heat pump add on". I wonder if the "Heat Pump add on" might be eventually replaced by a new version that has the same low rate but excludes the peak period. A combination of the two. * called "Power Move" and it runs to at least December as an experiment.

Very interesting @scottishjohn.

That would be me then. Do you have any LVT at yours? I cannot imagine you would give the job to anyone else.

Oh, because I am not going to do the whole house in one go. I am thinking two rooms at a time. Usually it will be the same thickness on each side of the threshold. The only possible exception is the Plant Room to Utility Room threshold. I might use floor paint in the Plant Room, but LVT (3mm) on top of self-levelling compound (3mm) in the neighbouring Utility Room.

A related question … When applying a self-levelling compound across a floor, what do you use at the door threshold as a barrier to limit the flow?

Fabulous, thanks guys. I am not sure I can match the high-levels of workmanship on display in both those, but I will do my best!

In my Plant Room around the UFH manifold I have a big hole through the concrete floor (filled with PIR insulation). See photo. I would now like to pour a 3mm self-levelling compound across the whole floor and add LVT (stick-down), including across the area of the hole. What to do about that hole - and give a stable base for the self-levelling compound and LVT?! I am unsure.

Trying to decide on basin wastes: "Flip" vs "click-clack" vs "pop up". Has anyone got one of these? I wonder what they are like in reality. Looks quite nice. (It's a McAlpine BW60SPH-CB). It's a McAlpine BW60SPH-CB.

Just to clarify… the Energy Integral for the "Vaillant Arotherm Plus" heat pump is the name given to a way that the heat pump's microprocessor controller decides when to turn off the compressor pump, and hence stop heating. And the same Energy Integral also then informs the controller when to subsequently to turn it back on again. (There is also another way the compressor turns on and off unrelated to the Energy Integral, but that's by-the-by). The Energy Integral in this case has the units of "º minutes" ("degree minutes"); note this is not degrees "per" minute. Simplified and only dealing with heating … the controller calculates the number of degrees that the "flow temperature" deviates from the "targeted flow temperature" each minute. This is then summed cumulatively each minute to keep a running total. For example… if the flow temperature in the pipe leaving the heat pump is 42º and the controller is targeting a 38º flow temperature then (42-38) = "4" is added to the Energy Integral at the end of that minute. If in the next minute the figures are 45 and 38 then "7" is added at the end of the subsequent minute. And so on minute by minute. This cumulative sum is the "Energy Integral". Then… when that cumulative sum of these figures reaches zero (from its negative starting point; default is "-60" but this can be changed in the settings) the controller turns the compressor pump off and heating stops. There are more subtleties than I have mentioned above … such as overrun of the sum and the control of the separate building-circulation pump … but that's the essence of it. It's simple and elegant. I suspect that cumulative counters are used commonly in electronic control-systems. Perhaps an engineer here could confirm this.

Persuasion: happy to discuss offline. (Vaillant after-sales had mentioned a cost of £490 to replace the board.) Yes the new board is now installed and, as you say, I took care not to forget the cooling resistor (I even wrote a reminder note in big-black-pen and stuck it on the appliance ahead of time 😄). Firmware versions now … Heat pump: 351.09.02 HP controller: 351.09.01 Interestingly, the Vaillant engineer also modified the opening on the other side of the appliance, the opening for the power connections. As you may know, there have been some reports of water ingress there causing a short-circuit and I believe that newer models have been modified as a result. In my case, he removed that panel and put a clear sheet of thin self-adhesive acrylic over the entire opening before refitting the panel. This gives an extra layer of protection for the underlying circuit board. He said it was Vaillant's chosen mitigation method and was done for me as a precaution. I have read online that others have solved the issue with a line of sealant along the top of that panel, which I was considering adding but it is now no longer needed.

Yes, good point. You are quite right. My new-build house has huge thermal inertia. The concrete raft foundation for my bungalow acts as a 55-tonne heat store. The UFH pipes are embedded deep inside it. The internal temperature for the dwelling changes on a time scale of days (sometimes even weeks). This means that it is far less important when I add heat to the dwelling. Day or night makes no real difference. This all means that I can control the heat pump somewhat differently from most homes and I can try to maximise efficiency … to save money (and the planet). Hence the unusual slant of my questions here.

Update. After a bit of "persuasion", Vaillant swapped the board in my Arotherm Plus free-of-charge. All good. Many thanks for everyone's help and suggestions.

Good advice.

Ah, I see. Well done. I have emailed them. Let's see how they reply.

Ah I see, that's unfortunate news. I will have to see how much Vaillant will charge to swap mine out in the heat pump itself. Did you ask Vaillant to change yours?