Nickfromwales

You just insulate the pipe, then the heat (loss) is contained but the slug of cold water is deleted. Straight off the cylinder is the larger bore, 22mm or 28mm sometimes, hot water pipework, so when running a basin hot tapo this becomes way more of an issue; dumping out the cold water before getting hot out of the tap to wash hands after using the loo. For the shower, or a bath, or filling the kitchen sink, utterly irrelevant, just way more of an issue with frequent use, low flow outlets such as basins. If you're happy to stay fully clothed and wash your hands in tepid water, please ignore me and loop away. FYI, I've never done that loop on a pressurised unvented cylinder setup, and never will. I only do a more significant anti-gravity loop if it's a vented cylinder and the CWS is constantly heated / 'hot'.

Do the same with the basin hot tap and report back please. You can keep your clothes on for that one The expense of continuous heat loss? C'mon..... we're talking pennies and the benefit outweighs the long term losses of the discharged cold water through the meter. Happy to stay up and fight for this one, as I'll win.

Nope. That's as clear as mud lol. Try again please, as even I am confused by that one!

You snooze, you lose fella.

I strongly expect I will be using a very different button shortly that will completely remove the problem.

Ok... Your attitude sucks massively, and as a moderator I shall ask you to either change your horrendous attitude, or go to another forum where being downright rude and disrespectful is allowed; there's plenty of them available. Another outburst like that, which you have now aimed at the general population here, will see you banned. You've incorrectly accused @Onoff and quite frankly I wouldn't give you any advice as you just don't seem to deserve it. A quick check of page 1, by yourself, would see he didn't comment there. This is a polite warning to adhere to forum etiquette and to be respectful and non-aggressive, and to be honest, I shan't be giving you a second one.

This is a major worry! You need to know exactly what the pressure leaving the PRedV is. Sometimes you can buy a 1/4” gauge and fit it into the blanked off port on the control group, but yours doesn’t appear to have a plastic blanking plug to use to fit this? Can’t see both sides of the valve.

If there’s no hot return circuit & pump, I promote this heat creep (it’s not thermo syphon as it can’t loop back) to limit the amount of cold stagnant water that needs to be drawn off before getting premium hot water out of the taps. @MikeSharp01 you need a gap between the expansion vessel test valves.

+1 Last one I installed has these. Much easier than a full drain down tbh. These come with a wire that you push through for security, a bit like the DNO fits to the fuse and meter, to prevent misadventure.

Just drill new bolts a couple of inches away, and grind off the ones in the way. No need to remove the ledger if it’s level and other fixings are kosher? Plus one on the washers being too small. They have just been wound into the treated wood which is soft and won’t give much purchase. Should be big square washers afaik.

Good point by @Marvin about the softener defo needing putting in to prevent limescale. Is this notable on any of the shower heads or taps atm? Can't rule out the possibility that this is causing a failure of the pressure reducing valve (cylinder control group that the expansion vessel is plumbed Into) by crud building up on the valve seating. May be best to strip this down and descale it with something suitable so it can be eliminated from your enquiries. As said, the test valve is right at the top of the expansion vessel. It is sometimes hidden under a black plastic dome cap which screws off to reveal the valve; a Shraeder valve like a car tire. There is no isolation valve for the expansion vessel as your generic G3 installer will have known thats not allowed (by him simply following the installation guide that came with it). You cannot have a means of inadvertently isolating the expansion as its then dangerous to operate it without such protection. You can buy a cheap pressure tester off Amazon and test the precharge pressure, and to do this you just turn off the cold mains and open a hot tap (making sure the boiler and immersion are both switched off purposefully). Leave the hot tap open whilst you do the test and note your findings. Test it before, during, and after. Make notes for discussion here. Close the hot taps, switch the water back on, and then go and run the hot taps briefly to get the spluts of air / water out, to recommission.

All this nonsense about issues / danger from using an isolator is just a mountain out of a possible molehill. We fit isolators early on, as roofs go on way ahead of the plant / M&E going in, and we just lock them shut with cable ties. Just put a sticker on to say “isolate only outside of sunshine hours” if you have any risk of a random 3rd party getting their idle thumbs on this equipment, eg it’s rented out, but anyone else working on this kit should be competent or yourself supervising, so the risk from misadventure is easily manageable. Anyone who disconnects a DC array under load will be very unlikely to do that a second time…..

After 16 years of constantly moving / doing its thing, don’t discount the possibility that the components (which don’t last forever) are nearing / at “end of life”. Stripping and cleaning / servicing will likely just start these stems and flow gauges leaking, as they all rely on tiny rubber O-rings which eventually just go D-shaped and give up. If you want trouble free motoring, judging by the multiples of issues arising, I think it’s time for an upgrade and a new manifold / pump set. You may be able to retain the actuators as these are all pretty standard fitment. Depends on budget, and whether you’re happy to just keep putting band-aids on this to get through winter. Cheap option: LINK Best option: LINK Up to you if you want to spend time / money (good after bad) treating a terminally ill bit of equipment. Ask Santa maybe 👀🤞 Also, just to cheer you up a bit more in early December, if your room stats ‘click’ are they rotary dial type (Honeywell?) basic stats? These are quite crude for use with UFH (huge hysteresis), so you may want to consider upgrading those too if over/under-shoot is an issue; rooms get too hot then too cool instead of one steady temp for eg?

A 12/14kw could suffice, depending on your heat load. 24kw is a lot, 30kw to space heating is huge. What gadget do you have coming?

These are the ‘stems’ around the pins, and the square head of the stem allows you to rotate the body of the valve; further down = less flow > no flow if fully seated. How old is this setup?