ProDave

Think of a bucket of ice. You put heat into the bucket and the ice starts to melt, so you have a bucket of ice, and a bit of very cold water (0 degrees). The water won't start to heat until all the ice has changed state to water. The energy is going into changing state. The latent heat of fusion The stuff in the sun amp works the same, but at 58 degrees, not 0.

I'll get the popcorn while I wait, this could be fun,

Looking at the position of the over pressure valve (not right at the top of the tank) that might be the Tornado, with the expansion vessel built into the top of the tank (so one less thing for the idiot to get wrong) @pocster how much more does the top of the tank extend beyond what is shown in the picture? But if it IS the Tornado version, is their enough room above it to access and service the expansion vessel from above?

Someone else will have to advise on the Sun amp's. Can they take heat in the form of hot water from an ASHP?

The reason I personally don't like push fit is my experience 15 years ago on our first self build. We bought an old static caravan, and as soon as we connected it to the mains water (I admit about 6 bar) one by one all the push fit connectors started blowing off in some cases the fittings actually cracking. I ended up re plumbing it in copper. It was probably a poor system used (I never did find out the make) and was probably 30 years old, but it has clouded my judgement about push fit plastic ever since. But the whole point of push fit of course is the pipe comes on a roll, not in 3M lengths, so you can do a long run where it is hidden without joints, and just make sure the joints at the ends are accessible. I have used some left over Pex/Al/Pex UFH pipe like this for one run that would have been very hard indeed to do in copper.

I am at the other end of the KISS scale, ASHP directly driving UFH ASHP does a good job of regulating the flow temperature so not much work fir the UFH mixing valve to do. No problem encountered so heating demand is very low at the moment and the ASHP runs at a very low power, or just stops for a while if the water is up to demand temperature. Unvented cylinder for HW and from past experience that will run 2 showers at the same time though we only have 1 here at the moment so can't test that theory.

That's a competetive price for unlimited data. The local wifi provider here wants to charge us £35 per month. Now all I need is Three coverage here.... Currently all we get is O2 and Vodaphone 2G so not a lot of use other than voice telephony. It looks like the shiny new EE mast within range is for the emergency service only as nobody has reported getting a public signal from it (one person reported it came to life one day for about half an hour)

Has he CLAIMED membership of any trade body? This comes up from time to time on the electrician forum, it is very hard to get someone prosecuted for doing non compliant work, unless someone dies or is injured. Most of the schemes do not seem interested in pursuing complaints against their members. BUT if someone is found to be using the logo but is not a member of that scheme, that seems to end up in court very quickly.

print a copy of the instructions with the bit about sizing the D2 pipe, bends etc highlighted.

Soldered copper for me with bends formed in the bender rather than elbows where possible.

If you are being offered only 600mm worktops, you are in the wrong shop. I can confirm my Howdens kitchen units are 600mm deep, and the very cheap Howdens laminate worktop is 615mm deep. Perhaps the sheds selling 600mm worktops sell 585mm deep kitchen units to match, and people wonder why the washing machine sticks out further than the cupboards,

I am sure all the "tradesmen" that feature on Rogue Traders believe they are the dogs danglies. That does not excuse the fact he has done dangerous work and charged you money for it. That in my book is fraud. It is individuals like this that force the honest traders to have to pay more and more to be certified.

^^ I would have added whoever spots the problem gets the job of putting it right.

I would be telling him to march AND refund my money he has taken fraudulently or it will end in court. Then get someone else who actually knows the rules to re do it all.

Yep the bloke is a cowboy. As in my thread that @Nickfromwales linked to above is has to be 22mm minimum, then depending on the number of bends and total length it might need to go up to 28mm. Ask him for his calculations for the D2 pipe and post the answer. I used bends on mine formed in the bender rather than elbows as they offer less resistance to water flow, but I don't think the calculations differentiate. And post a picture of where the D2 pipe ends up discharging to. If you end up getting someone else to put it right, deduct the cost from his bill.

Or do as I have and fit a dual rate meter that switches rate as the HP switches from heating to DHW (so switched by the feed to your 2 way valve) and then you have heating and hot water energy usage metered individually.

I did think that myself, but having observed what happens in a defrost cycle: The temperature had dropped below 0 having been (just) above 0 in the day. As soon as the HW demand came on and the compressor ramped up to full speed, you could see the ice forming on the air heat exchanger. After about 20 minutes the defrost cycle kicked in and melted the ice in a few minutes. I observed at the end of the HW demand, there was still ice there, but not enough to trigger a defrost, When it ramped back down to a low power for the UFH no more ice formed, but neither did any of the ice there melt. It wouldn't because it was below 0. So I don't think "switch off and wait" would work in any but a very few situations. Mine has a "silent mode" that you can select that limits noise by limiting maximum power. Next time we get a cold snap I will try that and see if it manages to heat the HW more slowly and thus avoid defrosting.

It is not just the missing tundish, but the D2 pipe should be at least 22mm possibly more depending how long it is and how many bends it has. This one looks to be only 15mm. If he can'r be bothered to fit the tundish and the correct size pipe, then how much confidence do you have that he has done the calcs to actually determine what size pipe it should be? And do you even know where it discharges And lets not forget the cage around the discharge point as it could be discharging boiling water.

That is largely why I wanted to mostly ignore the programmer that came with the ashp (and regard it as a curiosity / a means to adjust parameters) and wanted the heating system controlled by an ordinary central heating controller. I must get around to writing the manual and in particular the wiring diagrams so in the future a third party might stand a chance of understanding it.

Makes me laugh that it is frowned upon for someone like me to read the rules and apply them to the letter when installing my own tank, yet someone who claims to have the right ticket just ignores the rules. You see that in all trades.

Would an alternative be to make a new drive parallel to the hedge adjacent to the house, so you enter on the existing drive and turn right. No new entrance, no new dropped kerb, much simpler (but probably more area to pave) The permeable paviers have pips along the sides so when they stack together a gap is left for water to drain down through.

I have never quite understood these types of water heater. They seem a good idea to cool the house in summer and make use of that spare heat, but at any time you are heating the house they don't make that much sense to me as you need to replace the heat they suck out of the house,. I guess if that replacement heat comes from a heat pump, then in effect the water is heated by a 2 stage heat pump?

It depends for a start on what mvhr unit you have and what provision it has for boost and / fan speed control. My own I used immersion heater timer units (which switch a relay next to the mvhr) so all I needed was a 3 core & earth 1mm cable from the relay box to each mvhr boost switch.

What I observed when mine defrosted is the compressor and fan slowed to a stop, the 4 way valve operated then the fan and compressor started up again. It only took 2-3 minutes to melt all the ice then it stopped the compressor, swapped the valve back and re started. During the defrost it energises the inbuilt willis heater I assume to reduce the amount of heat it sucks out of the house.

I wired a house that had a system a bit like that. It had a massive thermal store, I don't know the capacity, but it was huge. It was "odd" in that it was not fed from any top up feed, but you were supposed to check the water level from time to time and top it up. It was heated with a WBS that put only 2KW into the room, and 10KW to water. The theory being you light the stove perhaps once a week and burned it until the tank was hot enough, then that provided HW and heating for the next few days.