ProDave

Can we have a closer / clearer picture of the jumble of pipes coming out of the floor bottom left of the photo. Following the copper pipes between the 2 manifolds, the left manifold has the hot pipe connecting to the right hand manifold cold. These are the flow and return to / from the manifold. So either one is connected with flow and return swapped (which is wrong) or they are connected in series, which I have never seen before.

The annoying thing is why was the warranty issued. The worst case suspicion is there was some detail done wrong on your half that the warranty provider was not happy with, but it was done correctly on the other half. Warranty providers inspections are often more stringent than building control.

Question. Has the downstairs UFH ever worked properly? i.e. are we trying to solve a fault (it used to work but has stopped working) or is it a new install that has never yet worked on the ground floor? Post some pictures of the ground floor UFH manifold please.

I would be surprised if the kitchen heat loss is really 1.4kW that would be more than half my total house heat loss at -10 outside.

That's it in a nutshell. That's why this needs sorting or a solution on the table before you conclude the missives. What did the home report say about the drainage (let me guess get another survey?)

That will say whatever the vendor told them when registering it prior to putting it for sale. I know of 2 round here with septic tanks draining to a watercourse and SEPA have shown no interest in doing anything about it. My suggestion of rodding it was to see just how far it went and if by chance it did go to the stream, you know you have a route to discharge a proper treatment plant.

It's part of the building warrant process and agreed with SEPA who issue a permit. Generally they only do so if land drainage is not possible which appears to be the case here. You could always get the existing tank pumped out and get at the tail pipe with drain rods and see how far it goes and who knows it might go all the way and you unblock it?

NO it's NOT "working fine" Clearly whatever soakaway it was supposed to have is either blocked, non existant or the water table is too high. It is just leaking it's effluent into the now boggy garden. Seriously, you need to factor at a very minimum getting the soakaway completely renewed which WILL mean digging up the field next door and re laying and so will need a deed of servitude. I would be having serious discussions with the vendor (via your solicitor) to sort out the deed of servitude needed AND reduce the price to cover the work you WILL need to do. You also need a proper percolation test done in the location you will construct the replacement drainage field to determine if indeed it is even feasible. Failure to do that could leave you with a non functioning drainage system without the means to fix it. If that is too much for you, walk away and look for a different house to buy.

Fundamental question: Is this a boiler just for the garden room, or is the garden room close enough to the house to be fed from the boiler in the house? WHY run the boiler at 70C, First thing turn that down to 55 or lower. You will probably have to run the heating longer but it will work out cheaper.

Top post. Why can't talking heads on television explain it clearly like that? Regarding old UK houses, rentals and EPC's. I am certainly glad to no longer be a landlord myself. It astounds me that buyers still seem to mostly ignore an EPC. You would have thought old houses with a poor EPC, clearly in needs of upgrading and lots of money spent, would be valued less than a modern well built house. but pretty "period features" seems to override common sense in most buyers eyes. (the exception being I bet no landlord now will consider a house worse than EPC C unless it is very cheap) There have been discussions here before about EPC's and assumptions, with one particular person having vastly improved his house. When he sold it, he explained all the extra insulation and air tightness and showed photographs of the work to the assessor, who promptly ignored it all and made the standard assumptions. Talk about banging your head against a (insulated) brick wall.

That makes sense. What I was reading from the OP is rainwater was getting in, THAT would have to go up hill.

I doubt the water is getting in from the condensate pipe, that would have to run up hill. You won't get anywhere without taking the cover off to see what is going on inside. Try drying everything thoroughly with a hairdryer.

What does it do if you turn the FCU off? Does it turn off all the thermostats? Simplest solution would be leave it where it is, but swap it to a fused connection unit without a switch.

Lack of long term planning. It was entirely predictable that post war baby boomers are now well and truly beyond reproductive age now and the opposite of boom is bust. But nobody thought of investing something during that boom time to fund the old age of those boomers.

We have no concept of energy security. If we did, we would not have crucified our oil and gas industry and we would be drilling all we have got to use our own to see us through until renewables make it largely redundant.

There has been a lot of "poor" reporting in the last few days. One being the energy price cap is increasing very slightly, about 25p to most households. BUT hold on, the main stream news does not drill down into details. It turns out gas prices are going DOWN 5% while electricity prices are going UP 5%. That is hardly what you want to convince people to switch from gas to electricity is it? But it gets worse. Why is this happening? Well gas is going down to reflect the drop in wholesale prices. So why is electricity going UP? That apparently is because of all the network upgrade spending so the grid can cope with all the new wind farms and increased electricity demand. At this point my blood starts boiling and steam comes out of my ears. Several people including the PM have told us electricity prices will come down as we build more wind farms. This RISE in electricity prices now, shows that to be a LIE and in fact as more wind farms are built and the grid is expanded, those costs are being added to our bills and prices are going UP because of the extra infrastructure updates. Don't you just hate it when we are fed miss information?

How you control it is another consideration. Radiators warm up quickly and warm the room quickly. Under floor heating takes very much longer to warm up and warms the room slowly. UFH is best operated being on for long periods at a low temperature. So if you do the split system as a minimum you will need to be able to set different times for upstairs and downstairs heating. UFH losses to the floor void can be massive without sufficient insulation. Most recon at least 100mm of insulation under the floor. A typical overlay system where the pipes may be laid in 25mm of insulation will result in big heat losses to the uninsulated part of the floor. UFH is all about comfort, no hot / cold zones / no radiators taking up wall space etc. It will not magically make a house cheaper to heat than the same house heated with radiators.

Probably 6BA then.

What do you call tiny? Old electrical boxes used to be BA threads, probably 4BA or you could tap it with the next size up metric tap. But BA size screws should be easy to buy.

What is the question? Looks like you have fitted the yoke into the back box and have a front plate / switch that will fix to that. What problem am I missing? Other than connecting to the remnants of the cable in the old back box (hope that is not 240V)

My wall mounted vents have a fine stainless steel mesh. They do a good job of stopping insects but they do clog up and need maintenance. You can't suck them out with a hoover as there is a louvre vent in front blocking a hoover getting close enough, so to clear them I take them off and blow through from the inside with the air line from my compressor.

HDD bearings are the one I marvel at. I know they are only supporting a small mass, but they can run for many many years / decades. So far my MVHR fan bearings are okay, but I had to replace the bearings on my ASHP fan at about 5 years old, so chances are I will be doing that every 5 years.

Go and buy something like this https://www.ebay.co.uk/itm/397148477114? That will enable you to test each individual leg of the circuit and identify where the fault is.

I still don't think we know if this heat pump is heating the house with radiators or under floor heating?

You can buy an old style, not calibrated insulation tester second hand on the likes of ebay for not much money that would solve this quickly if intent on doing it DIY.