Nickfromwales

No AAV’s needed for ground floor fixtures if the invert is less than 1300mm. The AAV’s relieve vacuum caused by flush water dropping at speed, but at such short drops this doesn’t become an issue at all. Saves annoying / ugly boxing in and the need for access to the 110mm AAV’s. Only 1x SVP needed, and you can reduce this to 3” and run it externally, like a faux rainwater down-pipe, if you don’t want to breach the roof at all. Defo no need for multiple SVP’s!

Never give up. “All pipes located in areas where subsequent inspection will be difficult or impracticable should be pressure tested before being concealed.” So it is covering every base, and open to interpretation, as always. Whenever bcos have been on site they’ve only ever cared about fittings being accessible (as in not buried in concrete / screed etc), and never about pipe. I challenge, show sensible management of risks, they say carry on. Look at the amount of UFH pipe in slabs and zero issues there. I only really insulate (9mm wall) when in slab to protect the pipes during the construction phase, leaving the insulation above ground as a sacrificial cover.

Dangerous territory sometimes, plus "he who pays the piper calls the tune", and that's exactly how it should be if you are competent to dictate (but also are someone who will take ownership of pushing for a bad choice and then having to pay to correct later without blaming anyone........dealing with this currently and it's a major piss-you-off)

Not needed as it refers largely, if not entirely, to fittings. No fittings = common sense can prevail. Probably spent more time typing this than installing 2 pairs of both solutions though, lol. Self-building at it's best (worst?), eg set fire to £500 worth of time solving a £300 problem. Then multiply!!

If they're not going through stupidly acute bends then yes, but you'd probably have to pull both out and feed both back in again unless its a big duct. They'll not need changing out in our lifetimes.......

It's a bit like PVA, and the floors, or any other flat surfaces stay very tacky for a few days. The screed was like the sticky carpets in a rough pub for days, but I was pleasantly surprised at how there was no 'overspray' on the vertical surfaces at all.

That's more or less cosmetics tbf, if considering chasing a burst pipe. Most issues are with failed joints. 99.9% of failures there are installer error, the other down to a bad o-ring or similar manufacturing defect. This is the joy of radial plumbing, as the dozens of buried (enclosed) joints is near zero.

@Dreadnaught may know one?

Both. All hope just got dashed. News-flash, wood absorbs moisture.......... Can't wait for the 20mm gaps when it dries out in the summer......... Will be like a saloon door in the wild west then. Builder gave a full refund so he could walk away without any damage to his reputation. Surprised he didn't garnish it with a credit. Please......... nobody 'like' this post, thanks. @-rick- you sir are a legend, god bless you and all who sail in you.

Embedded means when you cannot get to them afterwards without destruction of property (kinda thing). I could send you the regs, but it's late and I can't be arsed to write my version. You'll not be turned by simple folk such as myself, so barrier it is.

You just pressurised the house pipework most likely. You need to follow the last instructions and do this again to find out if the vessel is RIP.

Typing in my spare time, so to add that all these finger in the air designs are then backed up accordingly, after I submit what I want installed, and they (chosen commission agents or manufacturers) come back with green lights all the way, hence the SCOP of mid 5’s I mention above. You don’t actually need the numbers as the physics basically overrule in every case, x amount of heat loss requires the same to maintain 21°, so the heat pump will push that out as required. It shall take no more. As long as you’ve not oversized then pipe centres are pretty much as you please, I’ve done 100mm cc and @JohnMo has his sending postcards to each other, one with a buffer and his without, both performing extremely well / efficiently etc.

Why not just Hep2o?

Usually just proper duct tape, much as that may feel to be a bodge it isn't. Some duct will require a female adaptor, so the duct can slide inside, and others vice-versa, so you'll need to get exact sizes and compare the products internal and external dimensions to be sure Jack will fit into Jill.

I'm your man

You won't really have any option tbf, and the EPS is far friendlier to make a trough into. Then you have zero requirement for cutting or faffing with the PIR, which is a PITA to do. This is what happens when you are left in a room on your own with excess time, to start imagining things which are just never going to actually happen....... Snap out of it!!!! Conduit or duct for cables, yes, and I do these with 32mm or 40mm waste pipe, with a pair of 45's each end to soften the bend radii. 10mm T&E will zoom down a 32mm pipe (duct) with ease if it's from the kitchen wall to the island for eg, but don't expect to run this all the way back to the consumer unit!

Nope! This is wrong. The taps needed to be left open for the entire duration, so the bladder in the vessel was at its relaxed state. The pre-charge pressure expands the bladder like a balloon, so if you look into the open end of a brand new unit, you'll be able to poke your finger in and feel the bladder pressing up against where the water enters. What you do is open the hot taps and leave then open to fully deplete any pressure in the hot cylinder, then keep pumping until one of two things happens; a) you get the pressure to begin to rise, and you keep going to the required pressure (3 bar for eg), or b) you just keep pumping and the pressure doesn't ever get there. a) means you've been successful, so get yourself off to the pub. b) means the pubs out, as you need the money for a new vessel. You do NOT take the reading off the vessel when the cold mains is on.

MCS means that most who GAF are hands-tied by the forms they have to fill out and that they then have to take ownership of.

5kw will suffice, just will take a bit longer to fully recover a depleted hot water cylinder. If you plan on solar PV > diversion > immersion, or cheap rate grid > immersion then less of a worry. DHW just takes an age to heat up off at <5kw, especially if you've a larger home and use a lot of DHW. Factor in icing and defrosting, and then you're getting very close to 'undesirable' performance under duress.

Why are you ducting these? Just lay the 2 pipes in the lower layer of insulation, cutting notches out that allow for the pipes to be wrapped in 9mm wall insulation, and simplify! Your reputable installers are talking out of their b'ttoms. The hot feed will warm the cold feed, so when you open the cold tap it'll go tepid cold > warm > then properly cold again. Defo cannot and should not be able to interfere with each other; basic uk regs say the hot should always run over the top of the cold when clipping feeds around a property, so rising residual heat cannot affect the cold feeds, basic good practice for as far back as I can remember. These pipes have appx ZERO insulative qualities. Bonkers statement. No need for barrier / additional expense.

DHW capacity needs to be discussed properly too, as most will put a smaller cylinder in than is advisable which limits your capacity to store cheap rate electricity (or excess PV generation) as hot water.

For the majority, perhaps, as they're heavily bound by commercial worries; not many clients will pony up money for any kind of review / discussions / etc, so a rubber stamp is lifted and struck down onto the paper and barely any of these are available to gather evidence or 12 month seasonal feedback from (so we don't know what the masses are doing). Last couple I've done have been not much more than a finger in the air (a finger connected to a body and a brain that's been heating homes for over 30 years) and one we dialled into recently is at a SCOP of mid 5's. In a truly well insulated, well air tightened, MVHR featured build with excellent fenestration etc, then the outdoor temp has just so little to do with the interior temps it's barely worth considering. The main effect is the heat pump changing how it runs to suit the temp of the air it is extracting heat energy from. I've been in these properties over xmas with plasterers screaming at me to turn off the heating as the indoor temps are mid 20's and the plaster is going off too fast. Then I go show them the UFH pipes sticking out of the floor, zero manifold, and say to them "the heating isn't on mate". Then they ask how TF is the house so hot. I say it's from body heat, work lights, and solar gain. Completely agree that poor performing individuals are the cause of the problem, so, as said, choose a good consultant to guide you through the varying offerings out there, or get installers with very good reptations and proof of it, or fly solo and roll the dice. Bottom line is that each instance is completely unique, with the clients needing to be part of the equation (often just ignored), and the process needs to be far more holistic than it is; insulation, MVHR, airtightness, fenestration etc all play huge parts in arriving at a successful system design, and the way it then functions to suit the occupants, not just the basics that MCS asks for. The typical approach from most is very rudimentary at best.

How can this be true? If there’s no spares then you’ve zero other choice? Y branch cut in to existing run, a single socket 135° bend into that, and take the branch off to pick up the ACO. Standard practice tbf, and even if you did this with a foul connection it would still work perfectly well.

It won’t end up overheating if they turn the flow temp to a couple of degrees over the room stat set point. Can’t happen. I’ve been around enough of these types of projects to know this isn’t an issue, just lots of people like the complex math behind it all and then still just come up with the same conclusion. This really isn’t rocket science at all tbh, any any seasoned (and directly experienced) M&E consultant or ‘heating engineer’ (not the ones on their mothers side) should be able to just look at this holistically and call it. If it’s going to be an MCS certified job then it’ll just be about ticks going into boxes, and then the system fettled afterwards to perform to suit the dwelling based on real life experience in the actual address, and the occupants feeding back to the installer after a full 12 months of occupancy. Tick boxes don’t take the occupants own quirks or preferences into account, imho these are the most important factor but often get overlooked.

It's whatever someone (usually a salesperson) can convince someone else of what it is. A client (spoiled brat 2nd wife of a wealthy old chap) bought an £1800 vanity unit (no basin and no tap) and a £400 extension drawer set to go on the end. 15mm chipboard, and probably £200 of materials / soft close drawer runners / labour involved. By the time there was a sink on top and a tap, the 'sink' had cost near to £4k. Just picking the drawer front up broke the corner off it, terrible design where the mouth of the unit and the drawer front were 45'd and then became ultra thin on the leading edges. Thin vinyl veneer (black) and light chipboard, so any chip or mark was instantly visible. Utter dogshit, and I've bought better off eBay for a 1/5th of the price. Said brat was told by the salesman that is was a high spec blah blah, and she told her new husband to stump up or life would be hellish. After a bit more shopping she'd blown nearly £18k on a bathroom suite and enough tiles to do 1/3 of the walls and floor. Most of it was available online for prob half the price or less, but she wanted the retail therapy and putting on a pedestal, so off they went to be robbed blind in broad daylight with a huge smile on (her) face. The other side of the coin is my sensible clients who want value for money, but not "cheap", so when I explain higher spec systems that come in more expensive than other quotes they have had independently, from their own due diligence, they see where the extra money has gone and appreciate the improvements in quality / longevity / comfort / etc and are then happy to pay the uplift between my quote and the ones they have; most systems are bean-counted to be competitive, so are quite vanilla in terms of initial offerings as most know they're competing against others who have priced off the same plans. The 3rd side of the coin is the minority who ignore my advice and reasoning, go for cheap as they are insistent they have done their own investigations (with no industry experience or actual real life knowledge) and then complain when the uninformed choices they made have backfired and cost more / delivered less etc. To these people who think they know better, I say "fill yer boots".....no skin off my nose!