ProDave

Ours runs about 6 months of the year, October to March usually. Annual heating cost about £250

Check it is getting power first. Those pumps have a plug in power cord, check it has not come loose.

Hi and welcome. A very topical problem at the moment. Please open a thread and start by telling us what it does right and what it is not doing.

My dad was a plumber. When he re plumbed my first house there was a long run to the bathroom done in 22mm for the bath. I argued with him to fit a 10mm pipe from the hot tank to the basin tap for quicker delivery of hot water. He wouldn't, he said "the water won;t get there any quicker" It was shortly after that I decided to do all my own plumbing......

Another idea might be to raise your concern that you are upgrading the network for future houses. See if you can get a legal undertaking, that if future houses are connected to "your" new cable then the other new houses should be charged a fair proportion of this upgrade work and that money refunded to you.

You really DO need to get the installers back and don't take no for an answer. Have a written list of "issues" like cold radiators, unable to get the house to 20 degrees when it's only 5 degrees outside, noise issues, starting up in the night on it's own etc etc.

But this is a split unit, so no water goes outside so there should be no need to do anything to "protect" it. My own monoblock does indeed turn on the water circulation pump if the water temperature in the outside unit drops below 10 degrees. It circulates the water for perhaps a minute before switching off. It is in effect drawing a little heat out of the house to keep the water in the pipes warm. This is not a documented feature and I have found no way to turn it off.

Where abouts on that plan is the neighbours proposal? The danger is YOU pay for the new big cable, that he then just uses effectively for free. I would try and speak to someone technical. A Wavecon 95 is a 3 core plus N 95 square mm cable. If it is currently serving 2 properties then there us potentially one spare unsed core just waiting for you. Try telling them you are building a low energy house and would accept a 12kVA supply if the existing cable could accommodate that. Otherwise you need to do a joint upgrade with your neighbour so you fairly share the upgrade costs.

My old 1930's house ended up with central heating and a 70,000 btu gas boiler which is about 20kW You can certainly get an 18kW ASHP But to work best, it would have needed a serious amount of work to dig up all the floors to install insulation and UFH.

It would appear so.

There is a growing trend for you to need qualifications and need to join some form of "competent persons scheme" before anyone will believe you know how to do it and indeed allow you to do it. AND STILL THEY GET IT WRONG.

Precisely Years ago I bought a 1930's semi detached house with 9" solid walls. It had a large storage heater in the living room. That proved woefully inadequate to heat the room in winter even at it's maximum setting. So I had to light the coal fire, use a fan heater, or later I installed a gas fire (much later I installed central heating) But that does not mean "storage heaters don't work" just because that one heater was inadequate for that particular room in that particular house. I think the REAL issue is there are bands of installers going around fitting poorly designed / sized ASHP systems that then turn out not to work properly and it is those poor installs that get "heat pumps" a bad name. I know perhaps half a dozen houses with an ASHP and they were all designed properly and working well. Perhaps it is time for the law to state clearly that someone designing a heating system should warrant that it will work in all normal weather conditions for the house and it's location.

But this will only happen until the tank reaches it's set temperature. Is it really a problem if the heating goes off or down a little while the tank heats up (this is normal with a heat pump for comparison)

That is up to what your DNO will allow, but lets suppose you are close to the substation, there is plenty of capacity in the local network and you have a normal supply with a 100A main fuse, then in theory you could install up to 23kVA. They calculate on the basis that there will be times when you are using nothing in the house, so all that you generate gets exported and you cn't export more than your main fuse and cabling will support.

You do get some funny things with heating systems. Ine in particular I remember when I was working in a house , was the gas boiler, every few minutes would power up the fan in the boiler for just a few seconds then stop again. It was not particularly loud but that sort of thing would irritate me and leave me asking why is it doing that if it's not actuallt heating? and you can be sure the manual does not state is is going to do that. I suspect you are not going to find a solution that will make this particular system work well enough to heat your cold house through the winter and at the same time be quiet enough for your particular needs. I suspect your best bet now is the "not fit for purpose" card and tell them to replace it with something that is fit for purpose.

See my previous post, I think it shows that running flat out the system is barely able to cope with 5 degrees outside so will be under powered when you reach winter.

If it's 5 degrees outside and you can't get the house more than 19 degrees, then you are going to struggle when winter gets here and it's sub zero outside. I think we did ask earlier what heat loss calculations they did before fitting this system. It is beginning to sound like they got those very wrong and the system is too small for your house? As to running costs, the cost of running an ASHP is quite similar, perhaps marginally more than mains gas, so if you had say had a gas boiler instead, it might heat up quicker as the gas boiler would be more powerful, but the running costs would be about the same.

I would contest that. It is THEIR error. In a similar situation when we built out first house, we had a low quite for a supply from SSE, because their plans showed a cable they could use in an adjacent bit of land. It turns out that cable was not there, and they had to run a new cable all the way down the road from the transformer. They picked up the extra cost. I don't think the plan to feed two houses from an 8kVA transformer would have worked, suppose you both turned on a 19kVA shower at the same time? So argue on the basis you had a supply designed and costed and you entered a contract on that basis. If they want to alter the design at this late stage any additional cost should be met by them. Tell them to revert to their original design and use a 25kVA transformer to keep the neighbour happy.

Oh my, there are so many things wrong with that circuit diagram I don't know where to start. This is NOT a DIY job and one for an electrician, an electrician that understands inverters and can read the manual

I have the Horstman H37XL I didn;t think there were very many 3 channel ones to choose from.

Those are good prices, I struggled to beat those with a lot of hard searching. First thing the decision may not be yours. Anyone can install up to 3.68kW without prior apporval and then notify it to the DNO. Above that you need their prior permission and that may come with a network upgrade cost. So ask that question first, find out what you are allowed and what costs may be involved. We have a typical 4kW array with the standard inverter limited to 3.68kW output. I manage to self use about £250 worth of electricity each year with little going to waste export. To ensure the self use we use all the big domestic appliances in the daytime and divert surplus to the immersion heater, which ends up with about 1/3 of what we generate. If you go higher than 4kW it becomes much harder to self use it all, not least because you would need 2 immersion heaters and a big water tank to dump it all, so you would really want to be considering battery storage as well.

I have an LG ASHP there is a long thread about it and some issues I had. But 2 things to bear in mind. Mine was an old model unit so not necessarily representative of current units. And despite the issues I had, it is performing well. Who is the supplier?

There is a suspicion it might not be reaching your target temperature because it is lowering the temperature to slow the rate of rise to prevent an overshoot. By turning it well up high as an experiment will see if it is capable of warming up quicker than it presently is. We are suggesting this as an experiment. If you find with the temperature set way up high, the rooms warm up quicker, then this suggests the temperature compensation might need adjusting to make normal operation warm up quicker.

Look on the bright side. It's a knock down and rebuild now so he will get the VAT back.

2 port valves per zone would be an expensive sollution. Even in our well insulated house, on a sunny day it is noticable how the 2 living rooms switch off early, but the north facing utility room keeps running a lot longer. All on one zone that room might end up colder.