Nickfromwales

Are these under warranty?

Fractional. Some, yes, but I would say bumping up ton15mm PB would would exceed that value, and keys not forget about a skim coat which also has inherent heat capacity also.

Ok! That’s a first for me, as all that I’ve installed have been the other way around. So yes, a simple fix and deffo the cause of the water hammer noise you’re getting. A quick drain down, spin the valve round, fill back up and then to the pub to celebrate. ?

“A” connection is the UVC > boiler return, not flow, so the valve is the right way around just it’s normally on the flow, so in the wrong place afaic. Looks like it’s not plumbed in correctly but I just cannot tell without better pics / taken from other angles. Can you upload more plz?

It’s not cost effective to pay for repeated drain-downs and plumbers visits. https://www.bes.co.uk/motorised-mid-position-valve-3-port-28mm-17392/ Change of £40 inc VAT !!

It's your age lol. You had your Horlicks yet?

Yup. The diverter hardly moves, but a mid or 3 position valve has considerably more travel as it goes from heating > heating & DHW > DHW only.

Jesus! OK, the valve is cream crackered. You've had your money's worth out of this one I'm sure, so time to get the plumber in and fit a new one. Do not just change the head, it's the valve body which has killed the actuator head and you'll just be in the same boat in a weeks time if you do. Problem solved.

If the location of "manifold 1" sees a zone / loop that drops down and then rises again, then you'll need to allow the air that will collect in that trapped section to escape. You cannot have a zone or loop that resides above the manifold height unless you cut the pipe, expose it, and fit an automatic air vent to it, as the air then trapped would never get to the factory vent on the manifold. That secondary remote vent can be done, just it would not be my preference. UFH loops air-lock very easily because of the extremely slow rate of flow, so beware how you design and install or you'll need to periodically purge any loops which get air-locked. That is time consuming and laborious.

The most important thing is that the manifold stays as the highest point in the system so it can vent air out. So one can do the rear and half of lower, and one can do entrance and the other half of lower for eg. Doubt you’ll need 3 tbh.

18mm pipes in a thin liquid screed would not be my preference! Deffo need the pipes at narrower spacing than 200mm too with a thin screed system.

If it's a s creed then blue strip will suffice. If a slab, probably needs an upstand of EPS or PIRR about 25mm or so thick.

Some say 5-7 years, others say indefinite. Best to ask the manufacturer of the one your considering using. Milton technique is more for GSHP I think, where the longevity of the glycol is a serious cost consideration, plus the glycol cannot be dumped into the collector as one ‘slug’ as it will congeal and not function / protect plus it will cause serious problems with circulation.

The NSBRC is well worth a visit, but you also have BuildIt Live coming to Bicester Oxford soon too.

I wouldn't use FC tbh, and I've worked with it / alongside it and seen just how much of a complete and total ball-ache it is to use / finish etc. The marketing BS WAAAAAAAY over estimates its capabilities to accept fixings for mounting items too. I'm seriously unimpressed. If you put a screw in, it needs to be piloted first or the 'meat' just tears out with the final turn of the screw, just like a really dense plasterboard. And the FST is just the anti-christ in a tub. Use FC if you absolutely must, but, for the love of the fictional character known as god, PLEASE plaster it!!! FWIW, strategic use of plywood for heavy items such as TV's, or Gripit fixings for anything else will suffice for most day to day fixing to PB, plus I do not ever advocate the use of 'white' PB anymore, instead I recommend / use 15mm sound-block PB as it is much more dense and accepts these types of fittings easily. Weigh up the cost of the FC system, including the huge uplift in installation time / labour / consumables, and that more than adequately mitigates the higher costs of the SB PB ( plus you get the inherent acoustic qualities to boot.

They always do groundworks. This is groundworks not plumbing

A wise man I once chatted this over with, sterilises the primary pipework before introducing the anti-freeze / inhibitor mix into the system. IIRC he uses a wheelie bin with a submersible pump and a load of Milton tablets. He says this gives maximum longevity to glycol etc and he has a lot more letters after his name than I do so I tend to listen when he speaks. How many people here have done that is unknown.

Seems PolyPipe after a quick google. 18mm will of course attract a longer / large bending radius too....

I'm doing 100mm centres as standard these days as it's much better to have the additional cross sectional area for heat transfer, plus it increases the water volume in the system which helps mitigate against requirements for larger buffer tanks with HP's. If this is going into a screed, I'd say a minimum of 150mm centres. The No.1 suicide mission with UFH is to not install the pipe in the floor correctly / fit for purpose. A quick google suggests that 18mm pipe is from PolyPipe, so I assume the plumber would get the design FOC from his merchants!! You asking how many loops there should be etc says there is not a design at present? I would want to see evidence of the requirement, for the heat loss of the room, being more than adequately met by the system. Do not accept anything less. Also ask if the UFH will run independently, eg away from the rads, as this can provoke a requirement for a buffer to stave off short-cycling of the heat source ( boiler in this case ). It's usually in the boiler manufacturers installation guidelines to mitigate against this by design. The reverse / inverted method of laying ( above ) also gives considerably less resistance to the flow of water. Serpentine gives you a barrow-load of 180 turns where the water must continuously completely change direction which is not great. Plus if you google some heat signature images of the two layouts, you'll see the serpentine has a warm side and a cool side, eg where the heat diminishes from the flow to the return. Reverse / inverted does not suffer this way, and this is quite significant in a system where the pipe is in screed vs slab. Challenge your plumber, as you are the customer and it's your home and your money being spent in it. Use the Heat Pump / future proofing as your "angle" if you need to 'convince them' that this needs doing.

The water will pressurise both sides equally as they are made common by the pipe joining both manifolds Are the white caps all fully open? Same for flow gauges? Where did you pressurise? On the drain point at the end of the lower rail, using the top as the vent?

That’s not for us to say It’s your BCO who may fail it, so pass the onus on to the builder VIA EMAIL and state that “on his head be it should it not be passed”. Make sure he knows you will not be footing the bill for any such subsequent alterations to satisfy BCO.

Do you understand why this gap is a requirement? It is so that ground settlement / movement ( heave ) etc never affect the pipe. Pipes set in without have sheered in half because this has not been observed. It has zero to do with the functionality of the pipe, this is to ENSURE its longevity. Tell the builder this, and tell him to rectify.

Illbruck foam for the 50mm void, check different types for suitability. The website is quite helpful. Use cement backer board eg 12.5mm Hardi / similar as the closure plate.

Go for the Dwr Cymru option IMO. You are not going to benefit from any of the above suggestions with a gravity DHW system

Agreed. Pointless if the deck is not exposed to the elements.