Nickfromwales

There is a VERY strict rule about not having any type of valve / control between the cylinder and the EV. The PRedV does have throughput but it’s only the balanced draw point or body of the control group that fully satisfies that requirement. If you look at a few manufacturers installation instructions you’ll see the recommended connection points / detailed criteria. A quick google would have told / shown your guy this info for free. Bottom line is, it needs to be connected to the blanked off outlet on the control group. It can’t stay where it is. ? Doesn’t come in to it I’m afraid. UVC’s and G3 need to follow the manufacturers installation instructions strictly, and all you can do is add to that. You cannot move things around to try and beat the problem, as that will lead to further failures / compromises. Bigger question; have you not yet fitted the secondary PRedV and single check non return as per my earlier replies?

The T is before the PRedV is incorrect. The effort they went into chopping pipe and adding the T was a waste of time and money, as the correct position would have been the blanked off / already available 22mm balanced draw off union seen on the “control group” aka multi-block. I will concede that the retro-fit of the EV is a better / longer term solution, but ONLY if the pre-charge pressure is tested and checked every year during the annual G3 service & inspection. The 7 bar T&PRedV is fine, as it’s downstream of the 6 bar cold mains relief. In honesty, the sooner that ever opened the better.

So with that and the plasterboard channelled you you’d have 56mm to play with? More if it’s plastered plasterboard.

Remember to not use a single screw in the middle of the timber, instead go 1/3 down and 1/3 up with 2 screws per position so the timber gets uniformly pulled together and the glue fully ejected / displaced.

You may find that strangles the flow rate. Not something you'd want with 18 flats off it

Sky for the new one it is then lol.

That's the intention with the design of those screws, to pull the two pieces of timber together and for the head of the screw to not countersink itself, hence the large flange type screw head. The type of metal used also resists snapping, like you get with long woodscrews. I used 6.0 x 150mm Velocity screws to secure the ridge beam of my gazebo down, and most of them have snapped where the blank shank meets the start of the threaded section. I changed to hex drive timber-lock screws and they're way better. Heads are too small on both for what you're doing, hence the need to jump to construction screws.

..as in factory fitted. They are directly connected to the UVC by the plumber as the first thing off the UVC, if you're not going manifold / twin TMV ( one for the house and one for just the bath(s)) setup etc. You can mount them anywhere, but for max efficiency you keep them as close to the hot water outlet as possible to reduce losses.

If you’re selling the house with VM then migrate that with you. Fit SKY in the sale property and job done. ?

Nope. It’s either got an EV screwed to the top of the cylinder, and the external factory case of the UVC extends up to hide it, or it’s a bubble top where the hot pipe is extended down from the top to allow a pocket of air to be trapped to use as expansion. If the bubble top has depleted, you simply drain the UVC and refill to replenish the bubble or it’s the other type and the dead EV needs to be replaced immediately. If you leave the ruptured factory EV in service you’ll eventually have a full and catastrophic failure and a flooded house to boot. The internal steel body of the EV ( if it’s not the bubble top gone ) rusts away day by day, exacerbated by the constant heat and influx of fresh oxygenated water, and perforated. At that stage the cold mains pressure is free to escape and flood your house. For good measure, that usually blows whilst you are out of the house and the cold mains is constant so it keeps pouring out until you arrive home……. It doesn’t sound like your plumber is very experienced in UVC installs / repair I’m afraid. He may be a good general plumber, but this is a terribly dangerous scenario if the factory EV has failed, or a bloody expensive unnecessary repair if it’s just the bubble that needed regenerating. Have a look to see if the lid of the UVC comes off, easily, and you’ll have your answer.

@SillyBilly These

Explain more please. Baffle? Where?

Your BCO joins the others which talk from yesteryear in a lot of instances. G3 requirement kicks in with all UVC installs, and every single UVC I’ve ever fitted ( over the last 20 years ) came with a supplied thermostatic mixer valve aka TMV. You set that to 50oC and job done. If it’s a new plumb install then add a second TMV in parallel and set to 46oC and run that to the bath hot supply, or just fit a thermostatic bath mixer tap which is easier. Also nice to have a thermostatic bath mixer tap if hair-wash on a handset is required at the bath. What is the proposed method of carrying out the pasteurisation cycle? ASHP to power up an immersion?

?

You’re not really supposed to run 32 or 40mm more than 3m in normal circumstances, but when adversity strikes you can mitigate against ‘risks’ as per the above ( 50mm pipe and plenty of cleaning access etc ). Theres no way in hell that you can go to 32mm pipe for this, and I wouldn’t do it in 40 for more than 6m before upsizing to 50. What’s the issue with locating the 50 all the way?

It’s that compromise or a pump Take the compromise ! +1 Forget the above mention of 110mm pipe, and just run it in 50mm all the way with T’s and cleaning ( rodding ) eyes at each significant point or change of direction instead of bends. All bends need to be bends NOT elbows eg swept. 23m will be fine.

Plenty good enough

I prefer resin glued and construction screws just short of the width of 2 timbers / layers. Fix 2 together, flying and clamping and working from one end to the other so you can manipulate the timbers with additional clamps as you work along the length, then add the 3rd timber repeating the same method. The construction screws allow the timbers to be pulled together incredibly tightly, thus ejecting the excess of the resin glue, plus, combined with the info below, you should be able to marry the timbers to pull each other back to a straight pair, if so necessary. Examine the timbers for the ‘cup’ lengthways and sidewards and laminate them strategically to get the best overall uniformity. The lengthways cup should be strictly observed in any installation / scenario with the natural ‘deflection’ ( cup ) sent upwards so the cup naturally straightens out upon own weight and subsequent bearing of loads from above post installation.

Don’t press the quote button Instead, just click on and select the required text snippet from a members post. When you finish selecting you’ll see a small quote box appear, click that and the text will jump to your editor box ?.You can do that a number of times in the same reply so quoting multiple members ‘snippets’ in one post.

Nobody can “hazard a guess” at that ! It’ll need full SE input via calcs and those produced in a recognised format for conveyance to your BCO. You can get general advice here, not a replacement of your SE @Gus Potter makes a great point about the 3 timbers needing to be as one. You can then centralise the trio and make up the same deficit in ply each side. @SillyBilly to quote another members post just click on their text and highlight it. You’ll then see a white box with quote in it, click on that and it will open that in the editor. Also to ‘mention’ another member just type the @ symbol and start typing their user name. A drop down list will appear, and simply select from that. ?

If there’s a 10mm gap, go concrete solid and fit a 10mm blade of steel plate to create a Flitch beam and put your worries to bed. You could park a car on that.

Eh?!? If the cylinder stat is set to shut off at 50oC then the HP will shut down and the circulation pump will not operate ergo water that hot can never get to the HP. Any temp above 50 will just stave off the HP from coming on, and that’s all you need. If I was designing this I would fit a second 2-port zone valve in the return pipe exiting the UVC to arrest convection circulation, eg so the HP does not / cannot become an accidental radiator. Putting a heat loss aka dump circuit into this arrangement is just crazy. Any of that heat energy should be seen as useful and harvested in the UVC. 210L @50oC is mediocre, but 210L at 75-80oc is a lot of useful DHW. Any uplift in temp = more stored heat energy which absolutely should not be dumped away. What is the control methodology for the ST? Is it supposed to have a dump circuit and for that to be on a high limit stat on the upper 1/3 of the UVC ( 3rd party not HP or UVC controls ).

Don’t fit the cu yourself, just get the SWA into the cabinet and leave that to the sparky to do. Most sparks would likely refuse to energise a DIY fitted installation, let alone test and certify it. It will likely cost you money, not save it, for you to do work in preparation. Know your limitations, and where regs and ‘the right thing to do’ lay. FYI, I would walk from that job if I turned up to connect it and you’d fitted the CU. It’s not worth the risk putting your name to such a small job for the inherent liability.

I made sure the DNO had instructions to install their equipment tight to the left hand side. Everything was measured and drawn out so I knew it would all fit, prior to sending cables x,y & z to that location prior to the meter installation. Agree the integrity of those DP Henley blocks need to be preserved during installation, but there’s no denying that in some instances the effort is not just worth it….but completely unavoidable.

If the (horse) shoe doesn't fit.......