JohnMo

Would think the spiral patterns are more required where there are high flow temps and big delta T or/as well as doing very close centre distance between pipes. In well insulated house, low flow temp and a low delta T any pattern will be good.

I would say if you have an immersion either directly or indirect you need G3. The safety cut out on the immersion alone, isn't compliant as you need a minimum of 2 layers of safety. So you will also need the discharge safety devises also. In an indirect immersion situation, it would also be a pressurised system, so boiling temperature the would be above 100 degs and it has antifreeze even higher again.

Not sure where you live, but in Scotland you are not allowed smoke detectors in a kitchen they have to be heat, so that precludes most smart detectors as the are heat and smoke. The guidance actually states Google for example are not allowed because they are combined. Also you have to chuck nearly all smart detectors out after 10 years, because they are programmed to stop working due to the aging if the detection bits. And non replaceable batteries.

The reason they want pressurised systems is to keep air out and corrosion.

That's a lot of energy, bet it looses 4 to 5kWh a day. That's what 1 or 2 people person use a day for hot water. £980 for a 210L slimline UVC with a 3m2 coil, that's what I have just paid. Heat that once a day, run UFH on WC without any mixing. Heating 750L of water to 55 is nonsense, to get, not a huge amount of hot water and then blending down for heating? Why would you. A lot of heat pumps will not run open vented. Until mine sees above 1.2bar, it doesn't start.

Noise, bought a dMEV fan the blurb said it was silent - it wasn't, so really looked at the specs and compared to others. At min speed old one over 25dBA and new it's 10dBA sound pressure level. So really look at the noise levels that will define how much one running 24/7 will p**s you off

Sounds like tell the press and social media then think about. There is absolutely nothing to trial if the array is G98 or whatever approved, it's no different from an MCS install.

Also I know that Grant make the case for under rather than oversizing and the volumiser they sell have an immersion built in, with heat pump controller used to add immersion heat when the heat pump can no longer give enough heat to heating circuit.

I generally thought that is the assumption, even MCS use that model, you size for 99.6% of the year, not the coldest day you thought someone may have seen.

Then the heat pump you are installing is too small!

Not sure any of think that far ahead. Possibly only need a simple dT controller on a variable speed pump, to manage temperature rise across the PHE on the cylinder side. Or even simpler for a DIY solution - a gate valve to set flow rate on the cylinder side, and make the pump manual, then during commissioning set pump at best speed and use the gate to move the duty point on the pump curve to get the dT you want.

He is trying to heat up a couple towel rads for 15mins at a time. No idea why or what advantage it serves over running for a longer period at a lower temp. Add an electric element to the rad on a timer - or just let the towel rads be warm when the balance of the system is on - or both. Anything else is stupid complicated for no real reason and most (time splicing for example) almost impossible to program with a normal heat pump. should this read inefficiency?

Sounds about right, you heat lots of water an get very little out. That's a similar experience as my thermal store, hence why have bought an unvented cylinder. I heat about 180L of water an get a shower and some general washing up. Not the most economical use of electric.

Been there done it, really wouldn't bother again. Sell it move on, have the cash in the bank, so you can use when you need it. It can take you 4 to 6 months to sell and have the cash in hand, even if you started making moves today.

Would have agree.

To run a Willis cost effectively you need a floor that can store the heat and slowly release over the day AND be on a low rate tariff AND a reasonably low total heat requirement.

Our electrician did exactly the same. We are in Scotland - dry lined and taped. Taper expects the back box holes to exist, prior to starting his taping. I assume you are insulating, as well to help stop sound?

For that to occur you need one of the zones to be a mixed flow. You also need to run the heat pump at the highest temperature - that will need deep pockets. Think you really need to go back to basics on how a heat pump works best. You are just making stuff ineffective

Not sure the statistics can be believed, there is no way mine will ever show up as it was self installed. Nor would any other self installed ASHP.

Why do you think you can? Not that normal, unless you are controlling a mixing valve on the cooler loops. Most heat pump have a single flow temp for central heating, this may change depending on outside air temp

Just shows the disjointed thinking and message from a government playing lip service to most things including the environment. This isn't a Torry snipe, they are all as bad as each other including the Greens and everyone in between.

I've applied let's see how it goes.

Think running towels rails only from a heat pump is daft irrespective of the buffer size. Make then dual fuel, with an electric element. In the heating season run them with the rest of the heating system and any other time on the electric element.

Don't really see it making much difference to anything. I found them a waste of money and faff.

At any other time than at the very end of a DHW cycle, I have to look at the fan to see if it's on. Silent from a couple of meters away. Even at the end of the DHW cycle you would not class it a noisy.