JohnMo

A lot of micro climates there, we are 6 miles from Elgin and the same from Lossiemouth, all 3 places can vary in temperatures by a couple of degrees. Or is it feast and famine, great one day rubbish the next.

No as long as you can get up and into it's final position. Then insulate everything really well.

Suspect you have a couple of different issues. Radiator not heating sufficiently is likely radiator balancing issue. So more water going through the first radiators in the circuit and not making it the last one. So system needs to be balanced - or system needs a higher flow rate. A grant ASHP uses a flow setter valve maybe the plumber hasn't set this correctly. In the ASHP instructions it says how these are set up. Grant do stuff in a slightly strange way to make a plumber happy in most cases. So could be a wiring issue. I would make an effort to understand what is happening when the cylinder calls for heat and when it's up to temperature does it automatically switch back to heating. Find out what valves move or don't move at either end of the cycle. An easy way to do this is turn the cylinder thermostat down then select cylinder heating on the timer. On selection of heating via timer nothing should change, if it does you have a wiring issue. If central heating stays on all good. Then wind the thermostat up so you get a call for heat and see what moves and doesn't, then wind the thermostat down to put heat off does valves go back to original position. At this point the central heating should be back to normal - if it doesn't there is a wiring issue. When you DHW heating is that in hybrid or ASHP or oil boiler?

Or for manufacturers to sort it out so no one needs to mess with it. Atag boilers you just answer questions, and it selects the correct curve for you. So house type, heating type, insulation levels etc. Then you select up or down on the controller if you are not happy after a day or two and the curve is moved. Would say that is suitable for 99% of installs.

Other issue is these companies are all new start companies - will they be around in a few years? A car, you jump in heating is set to 20, system manages this with heating and cooling automatically. So there is nothing complex required to manage a simple curve. House too hot curve is lowered etc.. it should flip automatically between between heat and cool. I think Hitachi heat pumps do this already and have for years.

some more reading FLY528GB_v2_display.pdf AIVC-2.pdf Construct-Ireland-February-2011-2.pdf

Se my above post

Sad reflection on the piss poor training we give to plumbers. Monkey see - monkey do, I am afraid. Good at pipe bending though.

If the contractor has done his heat loss calculation correctly he knows the what the WC curve will be. So only fine finding is needed. If he was smart he would enable the second set point within the controller, this is normally controlled by a volt free contact. Set the calculated curve and add an additional degree to secondary set point. Add a monitored thermostat. If the secondary set point ever is called for the curve is too low, if house is too hot curve needs trimming back. For the home owner they know no difference when second set point kicks in. House just stays stable. All contractors should be returning to ensure system is working as intended and make any necessary adjustments. But many never do. My old boiler has this ability and so does the heat pump.

Doesn't mean it's actually cheaper, which is the main point that people operate in that mode. The house gets damp they get black mould etc. Aren't you actually demonstrating the opposite running strategy, with a small tweak here and there you could be running WC. The main difference in short on/off operations is the fabric never stabilises, the high temperature heating causes drafts, people feel cold feet as cold air from top of room is pushed downwards.

So two situations heat pump and boiler, both have similar effects but way more pronounced with a heat pump. The lower the flow temperature the higher the CoP on a heat pump, and boiler the more condensing occurs so efficiency increases. WC flows the lowest possible temperature all the time so best efficiency all the time.

I use cone filters in the extract terminals, you would be surprised how much stuff they keep out the ducts.

Atamate_SDAR+Paper+2019+(1).pdf

It's all indicative of cheap energy, we had many decades of cheap energy - no one cared, the consumer accepted what they were given because that was the norm and NO ONE knew any different. The professionals should have, but they had inadequate training - trouble is most aren't knowledgeable now in low temperature systems. Training is poor, everyone is an engineer (unfortunately there aren't many Engineers).

And not be hot enough to heat the cylinder (assume not combi). But most people just believe if you only have heating on for short bursts it save money. Forgetting they have a boiler capable of 30+kW and it runs flat out for those short bursts. So 4hrs flat out, instead of 18 to 24 hrs ticking away.

See no mention of the pipe inserts, so did you have/install? A video of assembly easier than loads if words https://youtu.be/QDJ2gUNuf-Q?si=lF9exiA8-baO2cDL

Or just fit a single one in a central location, or install in a remote location and have a timed secondary loop. If installing one get one with a large plate exchange and have better than combi performance for reheat - as I linked too further up thread.

Possibly, one the kids or partner closes them, are you going to go round checking they have been opened again, every day? Most likely not.

Or just do Hep2O and don't bother tube bending anything.

If it has an immersion that isn't being controlled by the heat pump, it will be compatible. If controlled by ASHP you may hit issues with the secondary cutout being bypassed. So may need a bit of rewiring to take away from heat pump. Be careful with those numbers that may be case in a hot country, which the UK isn't. Your maybe nearer say 1 or 2%

That is a small cylinder when your used to seeing a heat pump cylinder. Looks tidy. Nice insulation joints.

If you have trickle vents replace for humidity activated ones. Click vents or any other manual vent will just get closed at some point in time and never be reopened. Humidity activated ones will be almost closed all the time, only when required for they open. While your at dump the intermittent fans and install dMEV one (Greenwood CV2 or 3) You should only have trickle vents in dry rooms not wet rooms, as they allow a short circuit of air flow if installed in a wet room

So the main drawing would need to cross refer to the cross section drawings as different wall may be built in different ways. If your house isn't air tight don't bother with heat recovery. Fans and trickle vents are ventilation, without it everything goes mouldy. A decent smart dMEV fan will run a very low background flow rate, and only boost if needed. Trickle vents can be made to be humidity activated, so only open when needed. Think about the system and plan, it will be silent, it only ventilates at the minimum level all the time. You only have trickle vents in dry room, and dMEV fans in wet rooms. Heat loss is minimised.

You have a dinky heat pump, you could easily pipe in 22mm, so if using 28mm don't loose sleep. The difference in pressure drop is very small.

Your MVHR will do that on its own. We only use the extractor on rare occasions now (smelly stuff and only on low) MVHR does a good if it on it own. A house with MVHR isn't the same as a normal house with intermittent fans. House feels and act differently. Anything else is a design thing down to personal preference.