PeterW

Would be my choice too. Not keen on the FTC and it’s methods of control on the tanks as I am never quite sure what they are doing (plus the pointless legionella cycle) and I reckon there is just as much opportunity for the FTC to use the immersion as a backup heater if the tank isn’t getting to temperature but none of this is documented by Mitsubishi and the only way to find out is a clamp meter on the immersion feed. It also puts all your eggs in one basket as @ReedRichards says - you need some element of bypass.

Hot.. warm..? Didn’t say boiling ..? ? How do you clear the frost off the walk on glazing ….?? Shame you’ve not got some spares to see if we can experiment .. oh wait …

nope it doesn’t. The issue you have is noise from the pump in the hydronic unit as it has other things in there as well. They are all off outside. Wrong again … so the reason they want the tank is to stop the internal pump having to circulate water around the house to gain heat so that the unit outside can be defrosted. With the buffer, the external unit can draw on this assuming the unit runs overnight and needs to use frost protection mode. Simple analogy for you. Car windscreen is frosted up. Do you wait for it to defrost naturally, which will take ages and mean you have to delay going to the shops and you can’t get what you want, or do you get a kettle full of hot water from inside the house that has been preheated and use that ..?? Same principle with frost protect - either wait ages and run the risk that something adverse happens and not have the buffer, or have the buffer that quickly sorts any frost issues. And you need to post the model number of what they are proposing - PM me the proposal if you want

Ok. These are different things and you cannot mix them up. The current hydrobox has a lot of moving parts and includes at least one pump plus other components that “make noise”. This is a water tank and a pump that circulates water - I’ve just tried to record the sound it makes but tbh is so quiet that I can’t…!! Software is irrelevant here - you need to let them replace the lot and then it will be easier to understand if there are other inherent issues with your property. Who is doing the install ..? Is it Vaillant ..?

The buffer is a bIg tank holding probably 80-100 litres of water. There will be 2 pumps - one internal and one external and the internal one will only circulate water in the house and the one to the monoblock may well circulate warm water back to the monoblock to stop frost issues. I’d need to see the full schematic but tbh this is a better solution than the split unit.

diameter affects flow usually rather than pressure when pipes are long.

Water … H20… Dihydrogen Oxide… The reason this is not an issue is that there is no refrigerant unit inside the property (think a fridge) and no frost protect required to make this unit “do stuff” as the monoblock unit outside has 98% of the moving parts of your current system. The only thing left inside is a bog standard circulator - these things are virtually silent, and by that I mean they make less noise than a mouse farting. Finally… acoustic box can be built around this if all else fails and the mouse is particularly flatulent as it will also insulate the bits inside.

@thefoxesmaltings is there an existing supply and where is the water meter ..? If it is new I would put a 25mm supply to the house, then tee off to a 20mm up to the outbuilding with a second stop valve to protect that supply at the house.

JG should be marked, the standard grey nondescript ones I never trust ..!

W-Plan is worth considering on an ASHP to give you DHW priority and this just needs a single diverter valve only energized when UFH is active.

Single buffer is fine - just chill it to 10°C and run that into the floor. You will struggle to get a floor down to that temp anyway with air temps of 18°C so it’s not worth messing with multiple buffers.

Which brand of fitting failed ..?

You’ll never reach the boundary of the FTTP capacity on CAT6 as your limiting factor will always be switch performance plus the actual data stream source - you’re talking carrier grade switching at 10Gbps on multiple ports which you will never use in a domestic situation so a good quality full copper CAT6 cable will be fine everywhere.

Ring beam - essentially put a 6x2 across both ends of the floor so your floor joists are screwed to this (or use joist hangers for even more strength) and it creates a “ring” of timber. Latest span tables here but a C16/C24 44x145 will be fine at 600 centres and supported mid distance. If you’re thinking of putting anything heavy in the centre of the front span (French doors etc) then just double up the front joist or even just put an extra pier of blocks so there are 4 on the front not 3.

3x1.5m at 1° (assuming the slope is the 1.5m direction) is around a 26mm lift on the back edge. For 3° you need about an additional 52mm so the simplest solution is to get the contractor to fit a 50mm square batten along the wall edge, then a 25mm thick batten at 750mm and then re-skin the roof in 18mm OSB, screwed to the battens and the front edge. It’s 2 sheets of OSB, and 10m of standard roofing batten if he doubles up the back and it will go nowhere. Total cost is about £60 and an hours labour - ripping the roof off for that is not worth it.

JG definitely don’t fit 16mm PEX

Welcome - 4 kids, so assuming that 2 are sharing ..?? Master could steal some space out of bed 2 and wardrobes would be walk in behind the head of the bed - still leaves lots of space. Also, put a door on the en-suite… even a sliding one !!!

Price depends on a lot including the location in the UK amongst other things. There is also the issue of Building Regs / Warrant depending on where you are, and also what you’re doing with the old bathroom. Shoving everything up through the ceiling is the quick option (assuming no joists in the way etc) and then it’s how much is a piece of string for what you spend on the new one. Don’t forget you’ll also need to think about any windows (do they need to be obscured etc) and also how you will ventilate the new bathroom to meet regs.

seems expensive for a roof and doors and it’s not going to be much better than what’s there. that would be my choice - and yes you could do any shape in GRP as a roof. You’ve got around 12 sqm - even at £2k/m you should get change from £25k for a nice extension

sounds like someone who’s read their profile ..! We do ask members to update their profiles when they join as it’s useful when answering questions about building regs and other country specific items. And the list of all the forum staff is here as it always is.

If you are electric only then look to load shift to E7 / E10 and increase the DHW storage - use the floor and UFH as a heat store and you can push a lot of your load to off peak times. DHW needs to be sized by number of baths/showers but remember the recovery time for an ASHP heating a tank is about twice as long as a boiler if not more

I would work the spans out - tbh 6x2 would be fine here - and go the long way across so the 4m span at 600mm centres and you will need to just drop in a row of pillars at each end and one in the middle if you turn it into a ring beam. I would use 2 blocks on flat and then one on the top of them to lift the base but unless you’re on very odd ground then you won’t sink as the ground pressure from 9 pads will be negligible.

some only have one flow temp (older IVT for example) and you need to balance with a buffer for UFH. I’d agree with this - or even go to 9kW so the heat pump is running at 50% load although if you don’t have a buffer tank you risk short cycling as it’s unlikely you’ll get less than 1kW output with modulation

Sorry is this now a fully ready to commission ASHP / UFH system ..?? If so - and if there is no hydraulic separation between ASHP and UFH - then you need a mix of inhibitor and antifreeze. Inhibitor is there to stop galvanic corrosion as pumps; tanks and heat exchangers have different metals in them.

20% gross will be 2% nett - so on £34k he has £680 before his nett margin has gone. And if he has 4 guys on it and it rains, that’s a day lost and the profit down the Swanee. If you want to compare materials (Caber be Egger etc) then you need to spend the time and money specifying it to that degree. You’ll also need to pay someone with the experience and capability to do it so don’t expect change of £1k for a full spec and detailed drawings along with the breakdown from contractors. You’ll gain nothing in terms of price but you’ll get a spec you can compare. It may also be more expensive as certain contractors may buy bulk and you want something bespoke that their supplier doesn’t normally provide and you could be buying part pallets etc This is why a lot of price contracts have “xxx product or similar” within the BoM as do you really care what the deck is as long as it is 22mm MR chipboard or ply..??? I’d also need the comments by the GRP roofers - they are saying that for a reason, and I wouldn’t trust my house and it’s waterproofinf to something 6 times thicker than a cheap condom …