Nickfromwales

I did........ Every letter. It stinks. DIY of a gas pipe, and then use of it until someone becomes available to tell you if its lethal or not is 1000% unacceptable practice unless you live alone and have the only key to the premises. Interpret how you like. You cannot do this, end of. Your OP is worryingly indicative of someone who intends to proceed with illegal / lethal works, and are asking how to go about it. Even more worrying is a GSR fitter condoning and playing along. I wonder where he would be if the HSE were on site after and incident? A million miles away would be my guess.......

Yup. Unless it's lengths of 60m or above its fodder. I chuck loads away, just the sane as a builder will chuck a load of PB waste away. %'s of waste is inevitable and costed in to all jobs.

I 100% stand by my previous; that anyone signing off a gas install they've not witnessed being put in, or they didn't just come and pull in themselves, is a danger. You just don't play with gas, end of.

Exposed is legal, sadly, just hugely frowned upon with every person I have ever undertaken gas work with over the last 25 years. Just never done it. If you can get a spanner in there, you can get a blowlamp in there too. If compression is to be used, then the pipe needs to be mechanically fixed very robustly, so there is never any stress on the fitting. Downstream rotational force needs to be considered also, eg tightening a fitting on a pipe up / down stream of one you've just done can loosen it if the pipe is inadvertently rotated when working on the next. A lot of things to consider but you'd only be aware of these potential issues if you have previous experience and are already "programmed" to mitigate. The law says you are fine to blow yourself up, but not any other 3rd party, such as wife / child / visitor etc. Folk can do what they wish, this is just my 2 cents Just seen a lot of dodgy pipework in my time, some lethal.

Or an idiot. Anyone who signs off a gas pipe, that they have not witnessed the integrity of for every inch of the pipe, is a danger to themselves and others. It would be different if it was a friend or fellow plumber who's work was known to them, but for a one-off for a self-builder it is just lunacy. The sleeve through the wall should be copper, or a rigid PVC and NOT flexible electrical conduit ( as it is weak as a kitten and very easy to puncture. The sleeve should be sealed into the wall at each end, and then the pipe passed through the sleeve. The pipe should then be sealed with a sealant on the internal side only, so if the pipe ever failed the build-up of gas could only ever discharge to outside, not fill the house. That's the minimum standard I observe when passing a gas pipe through a cavity wall. As for compression joints, there should be ZERO compression joints other than at the source and at the appliance. Surface mounted anywhere else is a huge bodge and would never get past me. Compression anywhere on continuous gas runs = NO, simply do NOT use them, there is no need. If this is to save money to DIY, go save money somewhere else, this is just a daft idea.

@Adsibob If the runs are from hot and cold manifolds, then with the locations / distances as you describe there would be no need for an HRC to any of the outlets other than the guest basin and kitchen sink, IMO. The bath is so close that your infinite bath top-ups would only have to expel around a half pint of "cold" water before you got premium temp hot water out of the bath tap. That feed would be a 15mm from manifold, with the manifold fed by 22mm from the HRC. ( If your UVC has a 28mm outlet I'd be surprised? ) The manifold + HRC setup is dead simple; 22mm hot feed to hot manifold via 22mm TMV ( to maintain the B.Reg for 46oC ( max ) at the bath tap ). 22mm cold feed to cold manifold fed from the balanced cold output from the UVC 'control group' ( supplied with the UVC ). 22mm connection, from the UVC dedicated HRC tapping, to the HRC manifold ( HRC pump and NRV inline between those two items as required ) job done. 15mm radial runs to all cold outlets for simplicity 15mm radial runs to baths / showers 10mm hot feeds to everything else 10mm HRC returns to the point the HRC serviced hot feeds terminate immediately at the outlet. I use a Hep2O 15x15x10mm "centre" tee and a 10mm spigot elbow to perform these junctions. Easier than when Christ fell off his bike.

I read all that but it doesn’t say anywhere about making the “water wetter” ?. Kind of thing I’d write tbh, but made me chuckle lol. ?

More screws needed Tell him you'll pay for them!! Good job otherwise.

He didn't say he was typical This thread is demonstrating what CAN be done in light of the now-evaporated FiT scheme, eg so people here know what others like Dave are doing to 'work around it'. ?

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Just saw this. Yes, it would be good if maybe the slip membrane was supplied pre-marked. Sadly I wanted the screed in full contact with the subfloor for the two to act as one, ( for higher "thermal mass" lol ), as the above is a >PH project so had an extra bit of 'attention' with most detailing. An 8x4 of 6mm plywoord drilled at 100mm c's would have been the kiddy me thinks, so I could use marker paint to quickly dot a grid down. 20/20 hindsight eh ?! Thankfully I do these over-slab installs once in a blue moon, with all others going into an insulated raft with pipes affixed to the reinforcing mesh. Saves so much extra work!!

Actually you are spot on to leave a perimeter there, and I don't run into the openings either as that's the 'coldest' part of the floor in terms of difference in the cold from the sliders and junction with the outside walls vs the heated slab / screed. The amount of time you'll be stood barefoot on the "cold" 100mm of floor you've not piped = never. That one can go into the 'chill out' folder Makes it a lot easier to lay out with a few markings on the floor for ongoing sanity!! Top job With 40-50mm of screed, you wont be insulating any of it. I mostly do that where we are employing slab cooling for a client, vs no 'real-world' need when heating only, so don'y beat yourself up over that. Just be sure, very sure, that your pipework cannot lift ( float ) upwards when the pour goes ahead. With 40mm as the least amount you'll want zero movement from the pipe. Looks like you've got that covered TBH as you've gone on about the same gaps as I do, eg belt n braces. Tres bien, Rodney.

There are many benefits, and I never carry out an M&E project without manifolds for hot, cold, AND hot return. Sometimes the client only needs 2 outlets with HRC, but they still go on a dedicated HRC manifold regardless. Reason being is that the hot supply and the HRC both terminate immediately before the outlet, so to kill the individual hot to a particular ( HRC serviced ) outlet you need to be able to isolate both the hot feed, and the HRC loop to 100% shut off supply. As above, you can design out the need for an HRC, but those instances are usually based on an ideal layout / positioning of hot water device vs hot outlets, or with a caveat that a little delay to a couple of the furthest outlets is tolerated. Mitigated by correct pipe-sizing mostly, but still suffers if there is larger bore pipework before the distribution manifold, as there can be a much bigger dead leg there vs any of the terminal pipe runs. I often set up the hot manifold to have the HRC serviced outlets come from the far end of the hot manifold, eg opposite end to the hot water supply, so as to pre-heat the rest of the manifold and maximise the benefits created with shortened / correctly sized pipe runs. Current project will also feature occupancy switches ( PIR detectors ) to run the HRC only when a room is occupied, and only for a set 'on time'. @Adsibob I think with your hot return loop done with series plumbing, there are a good few disadvantages, and even without a manifold aka radial arrangement you should have had a better tactic for HRC deployment, particularly if you already knew the water would need to be recirculating for extended periods whilst you relaxed in the bath. Are all your hot runs very well insulated? I typically run the 15mm radial hot feed and its partnered 10mm HRC together, in a single wrap of 22mm dia x 25mm wall Climaflex pipe insulation, to massively reduce heat losses from that often lengthy pipe run. This also preserves the residual heat in the pipe(s) after the HRC pump has cycled and shut off, which reduces the amount of cold dead leg shunted back to the hot water device at each 'pump on' event. It would be minimum industry standard practice to install a suitable ballofix / other isolation valve immediately where the pipe run terminates at each outlet, so you do not have to shut down the entire wet system in the event of a single device failing / needing service. If you do not have these then it's a poor installation IMO. The manifold provides means of remotely and centrally mounting these isolation valves, so for eg shower mixers and bath fillers, often with nowhere to practically access such local isolation valves, can benefit from this also. This is the Achilles heel of series plumbing. Outlets have to share the flow dynamics of the pie run that feeds them all. That's usually mitigated with a very big pipe run at the hot water device, 22mm or even 28mm, then diminishing as it gets further away, usually down to no smaller than 15mm. If your hot supply is also the HRC loop then that can be more problematic, as it should arrive back at source via a non-return valve, so the return pipe side cannot 'back-feed' the outlet, ergo the furthest hot outlet will always be the worst performing / most affected outlet eg where other outlets are opened upstream whilst it is being used. A real PITA if that happens to be a shower. I converted to radial + manifold over 9 years ago and will never go back to series, unless its a flat with one bathroom / kitchen and they're all next to each other etc where it's then just not justifiable.

The secondary loop is created by tee-ing off each hot water feed, just before it terminates at the outlet. Also, why on earth would you have a bath on the HRC? A few seconds of full flow from the highest flow rate outlet in the building will clear the dead leg in s few seconds max. As the bath is high volume / low frequency, I NEVER have the bath on HRC. Only will I ever put a shower on HRC, if it's literally the other side of the building and then I'll combine the basin and shower feeds to kill two birds with one stone. Rarely will someone be using a shower and a basin in the same room simultaneously.

Usually only in district heating systems, and never in domestic ( not that I've seen in over 25 years of heating and hot water installation ).

Fair comment. The system should be designed to cope with the dwellings requirements, not the designers personal preferences. Your choice. You'll not miss the other 3kW tbh, but I would go with the 18kW boiler if you intend selling at all? There's little difference in price, but those few bucks buys a lot of insurance.

Yup. The only thing missing is flow gauges so you can set the flow rates, but you can do that with a bit of maths ( length of loops vs % that you open each gate valve ) so all good. Nice Reliance TMV on that rig, so that will be plenty reliable for sure.

With 2 Willis heaters working on the above project the house would see 24oC without trying, and 26oC when we'd not babysat it closely enough and a bit of cheeky solar gain had been absorbed. The issue with "cranking up the heat" is the choice of emitter, and the thermal time constant of the dwelling. Most see 1oC temp swings over 24hrs, so there is no summer / winter, and no 'timed' heating event as such. A party would have to be anticipated and the house temp setting increased at least 12hrs prior to, to have any effect on the overall house temp ( if a passive raft is the emitter not radiators for eg ). Then you'll need to 'set back' prior to the party ending, so the house can re-acclimatise afterwards ( and not overheat you when the crowd of 100W heating elements leave after scoffing all the free food and sumping your best vino ). This is very much dependant on the fabric of the build and it's energy performance statistics of course.

I did a full heating install in a 300m2 build, with insulated raft, and it ran at 18.5oC with an outside air temp of -7 with a £35.77 3kW Willis heater. There were 2 installed, but one tripped out over the xmas away period and I discovered it upon my return to site. That was with 2x 200mm open vents through the roof to atmosphere ( where we were due to connect the MVHR unit later downstream ). As above, if the fabric & ventilation heat losses are managed you can heat with VERY little input, so the 15kW device will more than suffice. I would put the UVC on W-plan ( hot water priority ) so it can focus on heating OR hot water vs the 2 combined. You mention a "heat only" boiler, but I'd recommend a "system" boiler so you get the expansion, pump and pressure gauge etc all in one box. Heat only will require a lot of kit outside the boiler so is unnecessarily complicated IMO. Plenty around from £600 upwards, but the Worcester Bosch for a grand is a decent machine with a very low modulation. Intergas and Viessmann IIRC offering as low as 1 1/17th!!

Yup, a load of members have installed away from the MCS register eg self-install. You only need to be MCS to register the installation for the export guarantee scheme.......but; Same as @ProDave, who uses his diversion and strategic consumption to avoid export / promote self-consumption...... which means no mandatory need to register.

Not if you hand the crowds a series of print-out's of the PV production, with a brief of the savings in not importing all of the electricity needs Then it's irrefutable marketing power.

Most of the systems we install exceed our estimates, and the breakeven point is typically year 13.5, so probably year 14.5 when you include the second inverter being fitted when the original one snuffs it. A robust panel ( we're either LG or Solarwatt ) will still be producing a useful amount of output in year 30, so worst case is 10-15 years of "free" electricity after breaking even. The maths do work out for sure, and the real question should be; "how long will you be at the property" for to see this return If you're moving out in 10-15 years don't bother, or just fit a token array ( circa 2kWp ) to offset vampire / base loads and give a bit of kerb-appeal when marketing.

Cool. Tell him to use plenty of screws!!

Do you have the opportunity to pull the lot down? DIY is possible with suitable PPE. Messy, but a far better job than over-boarding. In for a penny