Nickfromwales

Socket or coupler or even barrel.

Honest answer is I don't know how "safe" it would be to leave as-is, sorry. A temporary 'fix' would be to get a trade in who has a functioning brain, who could locate the joists and screw through these boards, through the original, and into the wooden joists, to get a mechanical fix. Then the risk of them falling would be mitigated.

Welsh joke, sorry!

https://www.screwfix.com/p/female-socket-x/77539?tc=FB3&ds_kid=92700055281954514&ds_rl=1249404&gclid=Cj0KCQiAkNiMBhCxARIsAIDDKNUekQc2LPr0XYZlnZpBllCNOCnMqaZTU1AD7MwI9JqB8oeKR1N3QtsaAgMIEALw_wcB&gclsrc=aw.ds ?

If it was, I'd have expected the moisture of the dab and the weight of the new bits of boards to have pulled the lot down already. If it is lath then it's deffo on borrowed time.

Removing this abomination will likely result in the original boards needing coming off. Prepare yourself for this to get worse before it gets better. Offer this chap a resolve. Tell him ( not ask ) that the only way you will let him finish this job will be for him to remove both the new "stuck" bits of PB and the original ceiling and for him to remove the spoil at his cost. Once at a clear ceiling, void of any ceiling boards whatsoever, employ a new person to board and skim ( plaster ) as required. Do you have some available funds to do so?

Have someone with you when you confront him. Another woman will do fine ( as I'd rather fight 6 blokes than 1 woman!! ). Your demeanour will do the talking. If you are firm and factual he will just have to accept this. If he doesn't agree, just tell him to leave there and then. This is your house and he has been invited in. Do not get into an argument, or raise your voice, but if he does, then tell him to leave or you will call the police and have him removed. Having a friend there recording on their mobile phone, just laid on a sideboard with the camera facing nothing particular will gather sufficient evidence for the police to enforce and side with you. Let me be totally clear here. This work absolutely CANNOT remain. It is not safe. There are even building regs guidelines for vertical studwork, differentiating between bathrooms and other spaces, where the studs have to be no more than 400mm centres vs the normal spacings of 600mm centres. That is prescribed so the VERTICAL walls can take an assumed load per m2 of plasterboard / tiles / adhesive / grout etc. This is the chuffing CEILING ffs!! Stop this guy now, agree a departure plan, and get him gone.

Wheel is too big. 10mm or 8mm is my preferred size, but there are many different grades of porcelain. I had some grade 5 on one job, and it was like breaking into the Hatten safe.

With W plan, yes, with S-plan you'd be better off with the 32 I suppose, but there would be very little in it AFAIC. The old Baxi 552's had 10-16kW max rating and these would be doing 10 rotten ( non-convector ) radiators for decades, in draughty 1g glazed houses with a small hot water cylinder also. The 24 will suffice either way, just these days everyone gets in a flap and buys the bigger boiler to 'be on the safe side'.

This is uniquely, the biggest bag of shit I've seen in over 30 years. Horrific. Did this clown screw all the original boards to the joists with new screws put in at 200mm gaps at least? The weight of the new boards, plus the dab will be huge. The risk of this falling and hurting someone is real. Get the lot pulled down, put in the skip, and tell this muppet to go back to the pub, after picking his horse up from the stables on the way........ Staggeringly shite. Do not allow this to be plastered.

What size wheel are you using?

You're putting WAY too much pressure down on the cutting wheel. You should barely be scoring them. Go easy, tiger!!

https://www.ukplanettools.co.uk/makita-djr185z-18v-mini-receiprocating-saw-bare-unit-djr185z.html?gclid=Cj0KCQiAkNiMBhCxARIsAIDDKNUTPeD7VSND-NSUnD2RhIRzVhBftiEKPOfDlxKp4XFol7P5rhfZ18MaAlrsEALw_wcB

Who's coat is that jacket?

These are what I use.

How far from the inside edge of the pozi to the internal PP panel? Maybe a recip saw will be the weapon of choice if you cant get a jigsaw in there. I'd rather buy a tool I know I'll use again vs a one-shot tool that will gather dust from that day onwards. Or, https://www.screwfix.com/p/erbauer-adjustable-holesaw-with-cowl-29cm-9-piece-set/2571V?tc=FB3&ds_kid=92700055262507123&ds_rl=1244066&gclid=Cj0KCQiAkNiMBhCxARIsAIDDKNXkPP7NLdl4oP0CRkpnaiIufaNeLkbkj04xNZWniNY_IihSVsxYZwQaAlU7EALw_wcB&gclsrc=aw.ds Can be used for cutting spots out etc later so multiple uses for that. The cowl on that will need to be removed to get in between the webs of the joist, and you'll need balls if steel for that. Me personally, I'd just remove a 600mm square of the external board, cut the PP panel from outside in with a jigsaw / multitool / recip saw and refit. Drill a centred pilot through the hole you just made to mark the external panel, after glueing and screwing it back to the 600mm c'd vertical frame spines, and then cut out with the jigsaw..

Combination heating arrangement here with a mix of rads and UFH, so the LLH provides both hydraulic separation, plus somewhere for the boiler pump to 'run off' to ( whilst it lights / pumps out an initial wedge of heat energy / waits to register the return temp to decide on the required amount of modulation ). It'll act as a hydraulic buffer, but also an accidental energy buffer too.

Jigsaw on internal, and guess what you’d use externally? ??? Yup. The same jigsaw. A few minutes work each hole. A 200mm hole saw will be cumbersome and single use. The jigsaw will become a friend through your build, alongside his best mate; the multi tool. ?

You don’t need 32kW imho, but I would do W plan if you have an UVC.

1/17th mod rate means that the boiler will very likely never short cycle. Having a LLH pretty much ticks every box so I agree with your plumber. He sounds a good guy. ?

A failed immersion in an Uniq was ( still is ? ) a ‘return to base’ repair which requires complete de-plumbing and extraction. To facilitate that repair requires the purchaser to palletise, and make available the spent unit for collection. Then reverse the process when it is eventually returned. To replace those immersions requires evacuation of the PCM and heat exchanger to get to the base of the cell. To do that, the PCM cell needs to be broken apart where it was once welded together prior to filling with PCM, evacuating the PCM and removal of the heat exchangers / thermistor string etc. A very involved process which is a non 3rd party option at ‘home’. The SAPV’s are serviceable at least, as I’ve done many repairs on them to date. Charming! ? If you post a pic of your unit with the lid off I can use my own way back machine to advise you on the job. Iirc I set up a couple of flexible hoses to flush all the crap out of the pipework and heat exchangers but a memory refresh would help if you can facilitate the above?

NO!! The nation needs closure on that journey, and you're the only one who can run across the finish line with that baton in hand.

Why didn't SA recommend you a service / repair agent?

In a Uniq the immersion has been made captive, so if that goes you’re completely Donald Ducked.

This is a Sunamp PV not an Uniq being discussed. The charge circuit fir the SAPV is a wet heating loop with that little immersion heater in-line. The pump speed was made variable to get the high temp flow up to a point it effectively melted the PCM, but fast enough to not allow it to kettle. The Y strainer which gathered crud in a pot the size of a thimble, and the combination of flow rates / temps / hard water issues saw these “terminally ill” from the get-go sadly, so the softer your water the longer it gets to live. I don’t know of anyone who had routinely serviced this Y strainer, to free it up from crud, but the ones I went out to after they’d failed were blocked solid and had cooked the immersion. Most were replaced FOC with an Uniq at that point.