ProDave

It looks to me like a component failure. As if it is powering up, but then tries to do something that draws a bit of power and the power supply trips. It starts and tries again in an endless loop. I doubt there is an entry in the fault codes for "power supply component goosed"

Gentlemen, speaking with my moderaters hat on, some posters are starting to directly insult others. Those posts have been removed. Please play nicely.

In cold weather, the outside unit of an ASHP can ice up. When this happens it needs to be defrosted. To do this, the system reverses for a short time and actually removes heat from the water in the system in the house to warm up and defrost the outside unit. It requires a certain amount of water in the heating system to do this, otherwise it would cool that water down too much during defrost. Some ASHP's have a backup electric heating element. Those that do, can turn that on while it is defrosting, so some of the heat to defrost comes from that and less from the water in the heating pipes, so less water volume is needed.

It's a different risk to asbestos, it won't kill you by poisoning you. The problem with raac, used for example for ceilings, is it's strength seems to decline and it might collapse without warning. I don't see that risk with your blocks.

What fuels do you have available? I am guessing you don't have mains gas, so it would be LPG or oil. Both need outside fuel storage.

What I am trying to figure out is how has it ever worked? It certainly has not been working as a timer fan. If that brown into the isolator is permanent L then of course the fan will be on all the time. If it is switched L then it would work as a non timer fan going on and off with the light. This is not something that just changes, without someone doing something. Has your T been poking around with the wiring without telling you. The proper solution is get a 3 core into the isolator with neutral, switched L and permanent L and take out the link in the fan and it will work properly as a timer fan. But something somewhere needs changing.

I don't believe it is faulty, I just believe it is not up to your exacting standard re noise, and not adequate for the high heat demand of your particular house.

I feel certain a SE could specify a new joist sistered onto the side of that joist, with lots of bolts, and then a section of the offending joust cut out where the flue is going through, to give you another 50mm or so.

Are you saying they have installed an ASHP and left the old gas boiler? or have installed a proper hybrid gas boiler / ASHP (first i have heard if that is the case) Do they use gas for anything else e.g. cooker? If not they could have the gas disconnected to save the standing charge if the ASHP proved adequate.

That's a shame. If only the joists has started at the other end with the odd space where it does not matter. Move the stove over one joist so the flue goes up through a wide gap? What sort of joists? If like ours, posi joists, the very end one is really a "spacer" between the downstairs and upstairs timber frame, it half sits on the frame and half overhangs the room, so it is not actually working as a joist. I feel certain with input from a SE that one could have a chunk cut out if it needed to. Picture of the joists and the offending too small gap?

I would not advise putting a treatment plant in shingle in a high water table area. I have seen one float out of the ground. Not pretty and not easy to fix. We were wrongly advised at our last house to do that. It is not a problem when it is full, but it means we can only desludge it in a long dry spell when the water table is low. To desludge it in winter with the water table high would be asking for trouble.

Obviously you cannot cope with any heating system that involves water and radiators because water moving through a pipe might make a noise and nobody can guarantee it won't. The company have offered to change your system for a monoblock which puts all the parts that can be expected to make a noise outside. That is the best offer you will get. A buffer is no more likely to make a noise than water passing through a radiator. But it seems you cannot accept that risk, you are not prepared to even let them try it. So the best thing you can do is rip out the present system, sell it on ebay as almost new not very much used, and install electric storage heaters that have no moving parts and no water. but be warned they might make the occasional clicking noise as they warm up overnight and parts expand.

FAR more details needed. Most important, has it EVER worked properly? If it did work properly and has stopped working properly, then WHAT has been done recently? That isolator switch is the normal 3 pole, but only 2 are used, so even if the fan is a timer fan, it cannot be wired and working as a timer fan. would need pictures of the inside of the fan, and the inside of the light switch.

Your existing one is s split system, being replaced because the indoor unit is noisy. The monoblock won't have this indoor unit, so surely the buffer tank can go in that place?

If it ain't broke, don't fix it. you should have refused a smart meter and stuck to your old dual rate E7 meter.

Then let them come and fit the monoblock, with a buffer tank if they insist. Give it a fair chance and only then discuss any new problems that come with the new system. Rejecting it because you think there might be a problem is not valid reason for rejecting it.

I have never liked E7 because it penalises you with a higher rate for the daytime. And that then forces you to use the noisy things like washing machine, dishwasher, tumble dryer etc in the middle of the night when you want the house to be quiet. Far better is a single rate tariff, and solar PV, then the best time to heat the house is in the daytime. using a heat pump.

Why have you only got 285mm between joists? That is awfully close. What sort of joists are they? This is a theoretical problem, i.e. you need some form of making it conform to a set of written regs. I have the same flue (with ample clearance) and from practical experience when the stove is on, even after burning for a long time, the flue is only warm to the touch, and I swear in the real world a piece of wood in contact with the outside of that twin wall flue would most definitely not come to grief.

Then make it a condition of the missives that they grant a right to lay a pipe to the river if you should need to. Get your solicitor on the case now.

Two options really. Dig a test pit at ground level, literally a 300mm cube hole and try a percolation test in that. If that drains away okay, then you could install a filter mound system, which is just a pile of very expensive graded sand and the drainage field on top, then covered in earth. You usually need a pumped output from treatment plant to pump the output up to it. Or if you have access to the watercourse (as in legal right to dig up the land and lay a pipe) then do that. It is by far the best solution. In my case building control rejected the filter mound and at that point SEPA agreed to discharge into our burn, but unlike in England, SEPA seem to want you to prove land drainage is not possible before they will agree.

My previous 1930's house had a slate DPC.

Cold tarmac is what the council wagon carries and 2 blokes go around shovelling it into pot holes and give it a quick run over with a wacker plate. Within about 2 weeks, nothing is left of it in the pot hole.

Without a thermostat anywhere what can happen is all the TRV's shut down, and the boiler and pump keep running to circulate hot water around completely pointlessly, and waste a small amount of gas firing up occasionally to keep that water hot. The traditional way was one room did not have TRV's instead that room had a room thermostat. That needs to be the room that takes longest to heat up, so you can be sure the other rooms are warm before that turns off.

Not a design criticism, but if you have the HW tank under the stairs, and you are having an unvented tank, you WILL need a drain for the D2 discharge, so you will need to provision a drain under the stairs. That will need thinking about and planning at floor slab laying time. Just pointing out as it may not be immediately obvious you will need a drain and will be a bitch to add later.

That sounds like a lot of different button pressing and confuguring. How do you backup and restore that lot so WHEN a part fails you can program the new part just as it was. If it was ALL contained in a script or a program that you could save and restore, it would be easy. I can see the fun of battling to make something work like that, but would not want to rely on anything I could not simply restore to a working system if one part broke.