Nickfromwales

To be accurately providing information, we’d really need to see detailed section drawings (or a really shit sketch on the back of an envelope) to say for sure. Whats the cavity insulation like?

This says single component failure then, not a build up of air stopping the show. One sensible ‘upgrade’ would be to have a manual air vent (thumb turn type) to vent the pipework atop the boiler, but I honestly doubt there’s a lifelong issue there if it’s run fine for a decade, plus then another 2 years after the rad swap.

In that case, up at that height, you can happily consider the steel and wood to be equalised for temp etc, imho, as they’re well with the heated and airtight envelope.

So many architects haven’t got a scooby-doo about these things. Even the SE’s tame associated, clueless. Constantly sense checking with Obi-Wan back at HQ, and just no confidence in anything he was looking at. Client rang me on speakerphone whilst the chap was on site, so I got to speak to him about the steelwork I spec’d and Obi-Wan had agreed over the phone; we made some slight changes, but beefed up certain elements to (over) compensate, and he was head-melted. After a lot of gibberish and flannel I just got a bit annoyed and said to go back to the office and just pass the bloody thing ffs. Myself 30+ years on the tools, and the steel fabricator & welder 35+ years, so I just said we’ve done more than a few of these over the years…..! Obi-Wan saw the adaptations, and signed it off without further comment. We put Bosig Phonotherm under the feet of the steels, where they sat on padstones, very nice product to work with and cuts / drills like a very dense particle board. Router / planer zoomed through it where I made profiles and recesses in it for the Norrsken doors and sliders etc. Blasted it with liquid DPC all around before then screwing it all into place and then blasting it with more. Available in sensible sizes too, unlike Compacfoam.

For floors at ground floor level, or for first floor joists?

“15 all……” 🤣

‘ckin hell…… ”Shots fired!!!!!!!!” 💣 💥 Lol. I thought it was only me that didn’t get their full 8 hours in last night

Most boilers have a drains off point at the underside of the boiler. Not all, but the majority. You can connect a hose to this, poke the other end down a drain, and open the drain off to pull water and air down / through / out of the hose. You do this with the system on and running btw. Can you have a look for a drain on the boiler? Dont mistakenly open the combustion chamber looking for it though(!) just look under it or take the white metal case off at most. If you don’t see it then, you don’t have one.

Panasonic uses the wall mounted controller for internal info. How the feck will yours know what's going on indoors if you don't have one? Other than the difference between flow and return, which would be cruder than a semi-sober welsh plumber.

WC will still prevail. Currently the rads are strangled. One step ahead, my man.........

Have we proven that L is getting there?

I'm not, the OP didn't say there was an issue there

Try again, lol.

You'd be shot if you didn't, ma' man.... How long has this worked for, to date, without issue?

No you don't. The (then higher) fixed flow temp will arrive at the TMV, and the UFH will see zero change in circumstance or performance. The FF rads will receive x degrees higher flow temp and actually do something. The rads go on TRV's to manage the difference in the size of the spaces that they are now able to satisfy. You balance and attenuate the lift in flow temp degrees at a time, until the happy medium is achieved.

You don’t have to keep saying sorry lol. Water hammer noises are difficult to locate / fault find, but as said the diverter (ahem) valve does a smooth transition, so would not be the usual suspect.

:reaches for drinks cabinet: 🙃🤣.

Yup. When we feather dry sand and cement screeds from 10mm to 30mm, there needs to be a very particular primer used, one iirc that stays tacky unlike PVA or SBR, to stop the layer from separating from the slab. From 10mm to 0mm you then use SLC.

From what I gather, and as per Dave above, there was a working light here before.

Yup. Defo the culprit if it’s not a diverter!!

Yup. If the old one worked, this one can be made to work. Light needs to come off and we need to see some pics, whilst I’ve still got hair! 🙃

Ah! I think you have the wrong valve. Google says this is a mid-position valve, and you should have a diverter valve. Can you confirm you have a mid vs diverter plz?

Pumps usually last a minimum of 10 years in a typical household, often much longer. Good to hear it’s sorted, but how old was the pump they replaced? Did they leave the old one there, and did they offer an explanation as to why they thought the old one had failed?

Ah. “No”. Whoever told you that needs to lay off the crack pipe. Sorry for the misunderstanding.

Can you post a pic of the internal piece that you need to connect to please? I’ve seen a few variations of these so want to advise according to what you have there.