JohnMo

We control around 2.5bar. Standing next to vessel, when someone opens at tap pressure starts to fall, about 20 secs later you see the pressure gauge rising. It continues a few seconds after the tap closes. Feels just like a mains connection, in use. We do have two huge banks all planted and the first summer we watered the lot most nights. 2 hose pipes running for an hour or so, at a time. I did get a little nervous about running well dry, but no issue. But well pump is down at 40m ish and have a Loch across the road about 6m down from the house. So in reality we should never run out - I hope. Wells have an issue - no electricity no water. Or you need big storage and the issues that comes with. So have generator, house battery and plenty of solar.

I looked also, but from I could see, the £7500 is England and Wales. Grants for heat pumps is for people on benefits in Scotland. Nothing for new builds anyway. I got my ASHP from eBay, there are plenty of bargains coming up. There were a couple of 6kW for £600, New unused.

Ours is about 25m to pressure tank (50L), then after the filters it splits, one side to house, about 8m, the other side goes to garage about 70 to 80m. Loads of flow, no issues at all. Once drilled and you run the water out for a week or two, you will get the water tested, and appropriate treatment and filters.1

Not the correct material or way to do it. For corners you really need the metal backed tape so you get sharp corners (internal and external corners) https://youtu.be/pp7AXv1P1GY?si=nlogtPCzn4psw6XZ

But don't you still have issues with the UFH and radiator when it's cold? Or did you manage to fix yourself? While the installer walks away with £15k

Our trouble (UK in general) doesn't enforce training that is meaningful. Our apprenticeship schemes are lacking. In many cases, can be blind leading the blind. To be a plumber there should be mandatory minimum training needs, this has to include low temperature heating systems and a deep understanding of it's design - we have needed them for efficient gas systems for decades, but no-one cares, that can make decisions. Instead we just get S or Y plan nonsense. This new scheme is just another scheme, it doesn't address the main issues of a poor quality work force, not due to their own doing, but because of poor training.

Take a look at iMEV total https://www.passivent.com/product/intelligent-mechanical-extract-ventilation-system-imev/ Each extract point can be demand controlled based on humidity same with the trickle vents.

Your first step for this is a room by heat loss. Then define your max target flow temperature. That will help you define the radiators you need, I would do this during the refurb stage. Or keep what you have, put new boiler in and set on WC and then assess what room may benefit a larger radiator. UFH is good on a new build but just hard work on an existing house. That is why we got ours, but cooling doesn't work with radiators. You need fan coils or UFH. But you can replace radiators with fan coils. Your existing cylinder can also be set to PDHW. A write up on the subject https://theintergasshop.co.uk/content/189-why-hot-water-priority-pdhw-is-the-reason-s-and-y-plan-should-be-banned

No need for that, go on YouTube and look at dry lining crack repair. You need something different to caulking as it shrinks too much over time. Some of the hybrid mastics stay flexible without shrinking and can be over painted. So may be a better alternative.

How old is the system? Was it ok in the past? Are you also having to top up water in the system? Have you checked the expansion vessel for charge pressure? I doubt it, the expansion vessel is there to stop the system exploding by giving an expansion route.

They joints look like a bit of a bodge, looks a bit like the plasterboard hasn't been jointed correctly. I.e. it should have been taped and filled etc, looks more like caulk and paint. Caulk has just shrunk away. I would pull out all the dross and do it properly, either skim or do dry line properly, with tape and the correct fillers.

Just sounds like an alternative to MCS with same cost adders.... MCS doesn't tell anyone to stuff a buffer in the system or zone to death, but installers still do it. Do you need either scheme - no Do you need grants - no If you want to install a heat pump just do it...

Still needs trickle vents

You should really let her out, that 5 years now.

On minimum flow rate I had to take the cover off to check it was running just couldn't hear it. Not all fans are the same. Had a different fan and was definitely noisy although advertised as silent. Just needs a live and neutral and it does smart humidity sensing.

Ventilation get a Greenwood CV2 GIP from eBay etc, about £50. Set to lowest speed will not heat it running, will just pull air though the small gaps in the building fabric. You need a 100mm hole through the wall. Heating electric or join it to house heating or a through wall heat pump heater.

Plenty of reading on here on what and how to do it.

You may need to get the system flow rates set so that you are not either under or over ventillated. Plus you may need to get the individual room flow set so the system is working as it should.

Add some walls, move some rooms about, on levels 1&2 or level 3?

S and Y plans basically set the boiler to a fixed flow temp - normally at or close to 70 degs or even well above that. The wiring plan just moves either 2x 2 port valves or a mid point valve to different positions - so you can heat the house, heat the cylinder or heat both at the same time. PDHW only allows you heat one or the other and also makes the boiler flow temperature different for each duty. So what happens you have a thermostat in each room and the room temp swings as the thermostat switches on/off. A bit driving your car with foot either fully down or up on the accelerator. WC or load compensation is more like cruise control, just enough throttle to maintain a steady speed, or steady house temperature. You run it all the time at a steady or may have a 1 or 2 deg setback at night. The boiler just ticks away and uses way less gas than than on/off thermostat demands and on and off timers. Flow and return temp to boiler make a big difference in the the efficiency of the boiler the lower the temp the more efficient it operates. And because the boiler isn't for ever switching on and off the boiler life span is way better I have had both the above and an Atag, just like the Atag its very efficient, very little noise. But I only recommend a heat pump cylinder - they are different from a gas boiler cylinder and unless pushed the plumber will install just a normal gas boiler cylinder.

Nearly every boiler ever installed is massive compared to actual heating needs. So doubt you will have any issues after refurb and extension. Heating load calculation is needed any way - not a plumber finger in the air and guess Aspects that are important Boiler modulation - boilers spend their whole life modulated to a lower output than design output. So look for a boiler than can modulate to 6kW or below (some will go down to around 1.5kW) S or Y plans are just shockingly poor for boiler efficiency and should be avoided at all cost. Design new system to be Priory Hot Water Demand (PHWD), this will boiler to run at a high temp for DHW production and a low temperature for central heating - this change alone could drop gas consumption 20 to 30%. Always install a heat pump cylinder (even with a boiler) this will give very rapid water reheating. Run heating on weather compensation or load compensation. Do not zone house to death - a couple of big zone is needed. Never heard of PvP solar - but all you need is Solar PV. Don't bother with solar thermal expensive and a one trick pony Cylinders - Unvented cylinder only - PV will divert to immersion if you want. No need for thermal store. Combi boilers and solar DHW. Yes it is possible and quite easy - you need a combi boiler that can take preheated water. Atag, Intergas are examples that will and the manufacturers freely state this. Instead of cold water feeding from the main to the boiler you need to add a cylinder (small 50 to 100L UVC) upstream of boiler, cold feed into bottom and top feed to combi via a solar diverter valve. Use immersion to heat so no coils needed in cylinder. Solar diverter valve, will divert water above 45 degs direct to taps and miss out the boiler - this stops the boiler firing up when there is no need saving gas. But over all you better taking an Unvented cylinder. I would choose a good system boiler instead of a good heat only boiler. Then the circulation pump is included and flow modulation is done automatically. I have an Atag boiler and think its great. Wouldn't look much further than Atag or Intergas boiler, they all PDHW out the box and weather compenstaion is built in, they are both very simple and efficient boiler makes. If your system starts to look complex - there is something not right. Best systems generally look like Boiler controlled only by boiler manufacturer controller - no third part stuff. 3 port diverter valve or 2x 2 port valves (on normally open the other normally closed) Heating system one side of diverter, and DHW cylinder the other. A system like that doesn't even need a wiring centre, every is taken directly back to the boiler

Defrost is a bit of a physics thing rather than brand thing. Really depends on location, but driven by the humidity in the air and it's dew point plus the amount of energy you are trying to pull out of it. We near the coast (6 miles) and can also get defrost at around 5 degs sometimes. But we generally flow at higher temperatures to batch charge instead of WC at much lower temperature. Try turning you weather compensation curve down a little, that will make the frosting take longer to occur. Or is the unit undersized?

You can get trickle vents with noise attenuation, so that's the noise issue sorted. You can also get them so they only open when required automatically, opening either on back pressure or on humidity rising. Add undercuts to doors and dMEV fans to each room with a tap. Something like a Greenwood CV2 or CV3 that automatically boosts also on rising humidity. Window trickle vents can be replaced with through wall vents that do the same thing in every dry room. With dMEV you would only have trickle vents in dry rooms not wet rooms. Your ventilation will be almost silent, no fan that makes a racket every time you switch the toilet light on. But your house will be pretty well vented but only when it needs to be.

If that simple just add a pump on either the flow side of the diverter to DHW or the return side prior to teeing into the return from the CH. Run at a fixed speed that enough head to get the circulation rate you need. Do the piping in 28mm. Simple enough.

For our concrete floors before we carpeted, we used a simple inexpensive concrete sealer, white milky stuff, similar to watered down PVA. Went on easy dried pretty quick, dust gone. Cheap as chips to buy. Epoxy used that also, super expensive, every tool you use goes in the bin, in a domestic situation will outlast the rest of the house.