Nickfromwales

You can get longer staples too, 60mm iirc. Boom. There goes the dynamite ?

I've never bothered tbh, and I've done loads. I took up one floor ( in a failing Everest summer room extension ) and that had been screeded over foil PIR. A lot of dark patches in the foil, but no issues with the screed, and no degradation of the PIR as far as I could see. It's only an issue whilst the screed is freshly laid and curing, and once cured it all plays nicely. Only real need for membranes atop the insulation is where you are having a liquid screed or a very wet concrete pour afaic. Take a core sample and see how thick the concrete is. He should have suggested this before giving that advice!! Yes, as long as it's the correct EPS with a compressive strength. EPS comes in various 'grades' so you'll need to tick that box. I'd go 150mm EPS > 100mm PIR and 80mm screed. If you want a really good screed layer, PM me and I will give you my mates details. He travels and has done all my screeding for over the years. Very good team and I've not once had to self level before tiling. All set out with lasers and to a tolerance of a couple of mm.

Agreed Just my option removes the TS and uses the existing footprint ( slab ) for buffering so that is hidden in the floor and consumes no additional internal footprint.

Yup. Those are what I’ve installed for every one of my high spec / “passive” projects. Regular TMVs are nigh-on fully shut at their lowest setting, and you can hear them ‘whining’ too which is a further annoyance. Way less pipe = way less water volume so not great at all ?. Anything less ( further apart ) than 150mm centres is also not recommended when utilising an ASHP as the primary heat source, and this is even more important in PH settings. Less system volume means bigger buffer or loads of short cycling. Much longer times to raise temps too. Current project all in at 100mm centres, apart from kitchen and utility at 150 as they are ‘inboard’.

Adjusting flow temps per floor is usually dictated by which types of emitters you have, so there is no hard and fast rule there. If screed / slab ground floor, and aluminium spreader plates 1st floor, you 100% need higher flow rates for the spreader plates as the losses from what is a much poorer emitter need to be mitigated against...by increasing the flow temp. I have done many like this, and, for eg, have had to run ~30oc ground and as high as 45oC 1st. Screed over block and beam on both floors may permit a unified flow temp, but as the heat rises the 1st floor in that scenario would likely need lower temp flow compared to the ground Water is being pumped around the UFH loops and back on themselves continuously at the rate that is set by the manifold pump and the calibrated flow rates per loop. Then you have the primary pump delivering heated water to /from the manifold, therefore a 2 storey dwelling with UFH on both floors would typically be utilising 3 or 4 pumps, dependant on the location of the TMV's. These pumps will need to be operating reliably at different potentials, so the basic requirement here will be for hydraulic separation of these pumps / circuits. The primary pump(s) will typically be single speed and flowing to / from the manifold(s) relieved by the calibrated or differential ( automatic ) bypass where they start the return path, but the secondary side ( manifold pumped loops ) will be constantly changing in potential, eg with fluctuations caused by changes in demand per loops / zones / by the actuators opening an closing. Also, with this approach and subsequent hydraulic separation, the flow rates through the loops cannot become influenced ( over whelmed ) by both pumps running directly in series ( the pumps never 'see' each other. Also good to note that pumps need to 'suck' water through TMV's, so you cannot have one remote TMV and then tee off to 2x pumps to give flow to 2x manifolds. You would need a 6 tapping buffer with 4 of those dedicated to 2x flow and 2x return for the 2 heating zone TMV's. Just a lot of extra fuss, confusion and all can be avoided by just blending and pumping at each manifold, like it's always been been done for a VERY long time. Also, if you don't want convection heat flow to the upper floor, remember that a 2 port zone valve ( my preference ) or a single check non return aka anti-gravity valve will be required. Next; to blend ( control ) water to the loops accurately, there needs to be a guaranteed supply of water that is cooler ( TMV manufacturer will give specifics for the required % of differential necessary to promote effective operation ) than the heat source input flow temp ( TMV ) setting. That is not going to be so if you are attempting to feed back / group the returns via to the buffer as you will be causing stratification ( multiple circuits flowing in and out for feeds, plus the same from the flow and return of the heat source ) and removing that guaranteed cold(er) water 'supply'. Water flow will take the path of least resistance, so the returns will just pull that mixed up body of water and add it to the return that goes into the remote TMV at the buffer. That is why the cooled returns from each loop are usually immediately grabbed by the local TMV at the manifold for use for blending where it needs to happen. It's only Nu-Heat which seem to like this option, plus a few renewable installers where TS's have been installed, and I've not seen anything resembling good results from that from type of arrangement with what I've seen ( on live installations ) to date. With UFH installs of mine coming up for 20+ years of reliable operation, I shall not be changing course with my ( standard?) method any time soon. PS. For anyone building to passive / very high spec, the type of TMV required for flow temp control if sub 30oC has a capillary wire from a thermo-probe which controls a TRV like haed on the manifold blender. If you move away from this you'll lose that type / accurate type of control too. Ivar is my weapon of choice, and you can see the setup with the capillary wire / probe / TRV here

The Ideal are solid boilers, but our budget offering, and typically we install those in rental properties or for 1st time buyers etc. Our weapons of choice are 1) Vaillant, 2) Baxi and 3) Worcester Bosch. I think it's fair to say that WB are making a very good boiler these, but for my own house I'd still go with my long-time favourite; the Vaillant.

Erm, no. The bigger rooms will already have more pipe, ergo more heat. The UFH design should mitigate through heat loss calcs for each heated space, accordingly. If there’s any doubt, just wind the pipe around at 100mm centres and simply create more volume of heated water per m2, but at the same temp. More loops = more heated area and ( IMO ) looking to heat other areas more by opening up flow is coarse on a good day.

https://www.google.com/shopping/product/1?q=manual+3+way+diverter+valve&prds=epd:15456469943751230827,eto:15456469943751230827_0,pid:15456469943751230827&sa=X&ved=0ahUKEwiq2ZHtkMb1AhXISsAKHaSFDwEQ9pwGCAU

Ah! OK, gotcha. ?. As is then seems the way. Had loads of issues when going to already installed ( by others ) UFH systems, mostly with the TMV not performing properly. Glad you got a result at last.

That adds some clarity. Why have you done that? DHW running at 45oC and heating at 35oC would give you a better CoP, no? That's how I set the most recent up, with just a LLH ( low loss header ). HP is just idling most of the time and has a nice easy life vs kicking in / out t higher temps. Gives a much better operational hysteresis IMO. Was a 7kw HP servicing a ~3.5kw demand at worst case. Ran near silently and I had to keep going up to it to check it was still 'lit and burning' by putting my head in front of the fan. The minimal road noise and surrounding noise pollution ( urban setting ) was enough to nigh on cancel the HP out altogether. I would not have wanted that running harder to heat a buffer and kicking in / out / running louder etc for this instance, and I could not see a notable ( short ) cycle which would have made me do otherwise. Each instance is unique, and this was a decent 'passsive raft' slab with a huge thermal time constant, so may have been different for UFH in screed over block and beam etc. @joe90 would you not consider getting the heating output temp down to see if that boosted CoP? With the buffer charge "not lasting long" I doubt that is doing much to stave off short cycling anyhoo?

If this is internal, then I'd also say run 28mm pipe ( copper or Hep2o ) and insulate yourself. As the delta between the pipe and the ambient temp of its surroundings are minimal, there is no real reason to go for pre-insulated afaic. Also, the pre-insulated pipes have a bending radius of around 1m, varies with external diameter based on how thick an insulation you went for, so near impossible to navigate tight bends also. I am using Primo Uno on an upcoming ASHP install where the runs are circa 30-32m from the heat pump, so I'm maxing out the insulation levels by running 2x Uno with thickest insulation available vs 1x Duo with limited, albeit still very good, insulation. For you, deffo stick with regular pipe and if you use Hep2o you can go very long distances with no joints, and then just slide un-slit sleeves of pipe insulation down each one. Then clip the pipe and insulation into place with either plastic waste pipe clips or powder coated all-round band ( from electrical merchant ).

Hi, and welcome. Some good choices there already so you're off in the right direction On this point, just remember that a typical 4kwp system will absorb around 28m2 of roof space, so, for eg, if your roof covering is costing £100/m2 you'll have a hypothetical credit note of £2,800 gifted to you from the savings of not roofing that area. Maybe that helps to at least get panels on the roof and DC cables in at the time of roofing, with a view to connecting the remainder of the system downstream / when budget becomes available.

Good prices and good kit the last time I used these people; https://www.heatershop.co.uk/electric-underfloor-heating-uk

OK. With an ASHP there is a 3 way DIVERTER valve, and with a traditional heating ( aka S-plan or Y-plan ) there would either be a 3 way MID POSITION valve. The diverter will ONLY allow heating OR hot water, eg never the two together, as with an ASHP there are pre-set temp changes per the duty ( say 40oC when diverter is flowing to heating and then 55oC for hot water etc ) so if I read the above correctly there is still flow going to the rads when heating is selected, and the rads gets hotter during hot water 'mode', and this is a brand new sealed and pressurised system? That tells me that the 3 way valve is either plumbed in incorrectly, or "passing". The 3 way valve has deffo been replaced and you witnessed that happening in person?

He's talking out of his arse. I've fitted new heating systems ( and fixed older ones too ) for north of 25 years, and what he says is a crock of crap. I've converted 50 year old systems from gravity hot + pumped heating, with pipework that looks like a rat-run with T's here there and everywhere, to new sealed and pressurised S & Y-plan and I've never had this issue. If the 3 way valve has been installed correctly, and more importantly WIRED correctly, then zero heat should get to any of the radiators. That would only be applicable if it were a gravity DHW scenario where the heating would get reverse convection flow to rads higher than the heat source. @graham1 The quickest way to solve this would be at ask your installer to put a gate valve in the flow to the rads, between the zone valve and the first rad, and then to close it. If the issue remains, further investigation into the plumbing layout is needed. Is this a 100% new install or a retro-fit new boiler onto existing pipework and rads?

OK. So assume that at over 4kwp you had to request permission from the DNO? Bear in mind that anything A/C coupled that is a generator adds to your total grid-tied generation / output, so, for eg, if you had a 4.8kw battery system and your 6.2kwp PV installed at the same time, you'd have been then asking for permission to connect 11kw of grid tied 'A/C coupled' generation. I'm not 100% sure where anyone stands adding this retrospectively or DIY / other, but it is ( technically ) something which you should be asking for permission to connect / add AFAIK.

If it’s doesn’t compress, fit the foam expansion skirting afaic. It’s an expensive mistake if you find it was needed.

Glasses it is then ?? I bought this one, apologies lol. Was the cheapest I found without ordering online. Select between 750w or 1250w or both for 2kw.

That doesn't have a timer. Plus, I wanted to go and pick it up and TLC had stock for immediate collection.

https://www.tlc-direct.co.uk/Products/HE2CH.html?ad_position=&source=adwords&ad_id=398484945570&placement=&kw=2kw convector heaters&network=g&matchtype=b&ad_type=&product_id=&product_partition_id=&version=finalurl_v3&gclid=Cj0KCQiAip-PBhDVARIsAPP2xc3khvVfd48mNNgTValG50Kyv4thZANH9mbEjeij0EZKwHF5aat3PqYaAmcVEALw_wcB Cheapest I found. Bought one yesterday and very happy with it for the money.

3 days minimum, unless you're happy to put 18mm plywood sheets down and police the activities. Even then this is not a great practice....

So you’ll be fitting whatever she says then

Radio linked systems are quick and relatively easy to install, and just take power from the nearest source eg light fitting with loop-in's, or a socket outlet with a fused spur connected for a 3a/5a supply. Basically you can pinch power from anything as long as it's fused down accordingly ( if a higher power circuit than a lighting supply ). @ProDave, can folk DIY?

I am also a tiler ( past business for over 20 years fitting high end kitchens and bathrooms ) and have never used a cement board / backer board, unless the client has bought them and has insisted, and then I’ve charged for the total pita they are to cut and finish. I do not like these boards as there is zero give and they do not confirm to the substrate well enough for me. The screws are everything in terms of purchase, and you either fit screws every 100mm or at 200mm and bond the boards on with Sikaflex for belt n braces. MR ( green ) PB for me on every single job, and tanking in every area of concern / wet areas. No leaks, no comebacks, and just about to become 25 years of doing them with all my customers still having my mobile number which I’ve had from day 1.

Don’t avoid sockets, just create a robust method to install, so as to reduced / eliminate infiltration, and put as many in as you like. Use fast fix boxes Link and just feed the cables through 30mm holes dead centre of each socket box location. Then you use a pad saw / other to cut out ONLY the amount of depth you need, through the PB and into the PIR. Allow an extra 5mm of depth for foam to expand into. Once the wall is prepped for the fast fix box to be installed you can use a blank module plate Link as a dummy socket face so as to be able to temporarily fit the 2x plate screws and tighten up the fast fix box ‘wings’ and then level off with a small boat level. Fast fix boxes are loose until the plates are fitted and the plate screws fully tightened Then you can use a foam gun to fill the cavity at the sides / rear and the hole the cable comes through for a bombproof install. Use air block foam such as Illbruck pro Link and that will also create a very good mechanical fix too as it cures significantly firmer than builders / typucal expanding foam. The OSB method is a no brainer, it just means fitting regular PIR sheets, then OSB over those, with long screws through for extra purchase where you predict there will be known loads affixed to it later, then the PB ( in each critical area ).