Nickfromwales

Go add them to the pile mate.

Insulate both runs with at least 19mm wall insulation. FYI, you don't really need the more expensive black neoprene stuff as the thermal values are pretty much the same as the cheaper grey stuff. Just try to leave seams unbroken and slide the insulation down the pipe wherever possible as that save a mountain of awkward taping up along the lengths. Tape joints well, gaps are bad.

Cool. Just with 10mm there and back, or even just back, vs 15mm there and back, the delay in getting the cold water (dead leg) gone eg getting the loop to circulate hot water from the tank to the tap is quite significant.

Also, don’t use a router! Stanley and a chisel is fine to break out small chunks, then pop a 10mm hole in. Once fitted over the window brackets you inject foam through the 10mm hole to fill the void you left from rebating. Don’t forget to mask the window frame whilst the foam expands.

Looking good Timber frame is deliciously quick isn’t it. What’s the plan for insulation and AT?

Based on it being tempered or not running 24/7.

Hi @weslev, see below Firstly is it actually necessary, then... < Up to you, cost vs comfort. At 15m you’re just on the tipping point tbh. I would be installing in hep2o and am fairly sure that the HRC is ok to be done in the same barrier pipe, is this correct? < Yup. Flow and return both in 10mm hep2o or should the flow be larger? does it matter? < I’d do the lot in 10mm if the hot return is on and left running vs pulsed via a PIR etc. If pulsed, then flow in 15mm and return in 15mm too otherwise it takes a while to get ‘there and back’. My design for this set up would be to feed the whb's and sink from the main hot manifold but reduce to 10mm, have the HRC come back via 10mm to a return manifold specifically for these three returns, then from manifold run to an isolation valve, followed by a non return valve, then my secondary pump, a final isolation valve and then into UVC somewhere in the upper portion of it if at all possible. Is this logical. < The HRCs need to come back to individual manifold ports, each with their own isolation valves, same as the hot out manifold; so each pair of hot and hot return can be isolated. This avoids having 3x isolations and a lot of exposed pipework at the basins. To save faffing on any technical controls, run the HRC from a programmable pump. < Doesn’t need to be technical. It’s on or off / timed, or triggered by a motion sensor in that room. Typically I work on houses where we’ve installed a decent chunk of solar PV, so I just set these to run all day (if clients are retired / working from home) or on sensors / timed for all other situations. For the retired / other folks the system reverts to the sensors at night, and runs constant through the day, as losses are largely offset by PV anyways. So if you get up to go for a pee, by the time you’ve done the deed and want to wash your hands, the hot water is sat at the tap waiting for you. Resurrecting old threads is fine, good to blow the dust off them tbh.

Excellent price too. Cheers, not seen that one before tbh as I just run to Grundfos Comfort these days. 👍

Took the words right off of my keyboard lol. Damn right. I'd rather put the other £800 into everything else.

You have a cavity wall / masonry build yes? If so, the foam will be subject to the conditions within the cavity, dripping condensation off a snot or tie etc, so I would use the rigid plastic for longevity. I'd use 200mm plastic through internal leaf, with the foam 180 inside that, and then lose the sleeve as you get to the inside face of the external leaf, drop the hole dia to 180mm and then punch through with the foam to the outside facade.

Get the stats from Telford too. "Go compare" lol.

If it is a generic UVC you are after, then you can also try Trevor at cylinders2go, and mention the forum.

I use the McApline on every install, and all projects are airtight etc. These just go to the soil stack wherever that connection is practically made. The G3 regs state the maximum length of the D2, including reductions for 90° bends etc, so you may have to beef that up to 28mm

👍

And have you started filling / sanding the FST for the Fermacell yet? If you gave that job to inmates, the crime rate in the UK would drop by 50% overnight. Seriously consider a plaster skim over those boards, it’s punishing work with very questionable results.

Get over it mate

The cold inlet is at the bottom, and water will take the path of least resistance to exit the cylinder, ergo the hot water at the top will make its way out. Me, personally, I don't like the "bubble-top" arrangements, as these need to be drained down periodically to regenerate the "bubble", and I would have an expansion vessel without a moments thought. Then you are at true '100%' useful capacity vs space / size.

Is the ply the final finish? I've worked on a number of MBC PH frames, from only being the M&E consultant and contractor right through to finishing complete homes (coordination of boarding & skimming etc), and can say with confidence that this is a non-issue. Self-builders are notorious for over-thinking and micro-managing, largely because they are face to face with every single tiny detail, plus they don't want to have to redo anything from un-investigated / non-mitigated misadventure (having often zero prior experience to fall back onto). One of the reasons this forum is so highly valued. On a SIP's TF dwelling that I am currently working on, I have recommended that the client use (x)mm Jackoboard / other generic insulation tile backerboard to suit each reveal. Also, to use this in the openings for the skylights / lanterns. You affix with multiples of screws (prob 100mm o/c max) or bond on with something like CT1, screws if over a membrane, or screws plus CT1 if any other (such as the airtight green OSB etc). 2 sets of skim over that and you're 2 birds one stone, and any worries long gone away. You can recess the back of those boards to accommodate the window fixings, as tbh these are the only significant cold bridges on an MBC TF (those and the skylights which they need to rethink their design on IMHO (sorry!)), remembering the TF is pretty much kosher and the issue is caused by the windows going in after MBC have done their bit. Using packers behind the PB fixings to create an air gap is probably more than suffice on an MBC PH TF, and is 100-fold better than what is in most homes at this moment, without having life-changing losses / cold bridges around windows!!

Hire a Spit nail gun. Will make clipping / mechanical fixings a doddle. No more drill / plug / screw etc.

It’s no secret that for MVHR I favour Brink equipment from CVC Systems. Whacking in some more of their stuff atm, and they’ve delivered great results on every install. Tres bien. 👌

Oh, and in a property that size you should do much better than 0.6 ach. The smaller the volume the harder it is to get a good score. Last few MBC TF jobs I’ve done have got 0.26, 0.27 and 0.25 results, as their airtight team are very meticulous, but I am even more so and bolster that with a bit more tape here and there plus AT foam anywhere that it looks like that would further improve things. @Russell griffiths got .28 on his DIY Nudura build iirc. That correct Bruce?

MVHR is requisite in an “airtight” residence, you’ll go purple and your eyes will pop out if you don’t install it. Not entirely true, but of course you will need to shift humidity and CO2 etc, plus introduce fresh, breathable air, so the “does / doesn’t work” comment I think mostly pertains to the efficiency and heat recovery values vs function per-se. I, personally, would just look at the highest efficiency and most robust (longevity) unit I could afford, and then I’d save up and buy a better one These are going 24/7/365 so have to be designed, configured, and chosen well to get the dividends. Any unit will ‘move air’ btw.

Let’s keep this on topic please folks.

I would take a blend of both. There are a lot of very well versed individuals on this forum, and I for one have zero ‘credentials’ to relate to building a certified passivhaus. However, I recently engaged with a PH certified architect, 25 years of PH design experience, and I got my design in at 88% efficient vs his 87%. He asked me a lot of questions, I gave very robust and reasonable replies, he conceded and the client then changed the MVHR design (well, the entire MEP design) and supplier on my say-so (and agreed to accept they’d lost £1k on the 1st design deposit). A PH certified home builder now builds differently, after 30 years of PH experience, after meeting me and hearing how I have approached creating homes that consider M&E etc and how we’ve integrated things on other clients previous builds. In terms of qualifications, I have a clean driver license, that’s it. But I do have bucketloads of tenacity, a passion for what I do, and an unquenchable thirst for knowledge. Most of the stuff I’ve learned has come from exchanges here, with invaluable input, argument, reason, and real-life data (there’s a HUGE amount of it here if you want to spend some time digging). One PH certified architect overlooked insulation in the foundations (😮), also didn’t have any clue about MVHR or space heating. Credentials coming out of every orifice, none that they understood or practiced well afaic. 💩 I’d rethink your confidence in ‘all that glitters’, as only a select few turn out to be gold… but I certainly do hope you have some of the best at hand. You’ll need it, as there’s a LOT to correlate and execute correctly at yours.

You’ll also need to dig out about 1m of trough to facilitate this repair, as the pipe needs to be apart by around 15-18mm to allow the union to be formed, then it needs to be pulled together by that 15-18mm to allow the inserts to seat into each side of the coupler.