Nickfromwales

160mm insulated is 250mm finished, external dia, as above. Not a 250mm duct

Beer and Toblerone is my Xmas staple tbh. “Get out of my head!! 👉”. lol. If this has worked for 20 years do you really want to spend on a full overhaul? I would never fit an arrangement where the manufacturer has the pump pumping downhill, instant “no” for me. Most pump manufacturers will show this in the installation instructions with a big ❌. I fit the Ivar setups from underfloor heating parts. Entirely up to you, but these are far superior and have never given me a moments trouble, and the TRV head and capillary feed thermostatic blending valve is way better (smoother) than the standard TMV’s afaic. Your call.

Mechanically removing the worst of it is the 1st step, eg a Stanley blade / scraper, and a plastic removal tool (Amazon jobby) will get you so far. Then you’ll need to try Multisolve from CT1 which you spray on and leave for a while, then rub more into the sealant to remove it; it emulsifies silicone etc and cleans the remnants off pretty well ahead of new works. Use a traditional cotton dish cloth for the cleaning phase. Good luck, it’s a pig of a job.

Amen. My tired thumbs were NOT looking forward to typing out similar. Beers on me. 🍻

A 20 year old pump has certainly served you well, so I’d defo say it’s time for you to treat your heating setup to a heart transplant! This would also be the next item in the process of elimination anyways, so if you’re summoning a plumber to site then you may as well max out on the value of that visit. So yes, get the pump and the AAV’s done in one hit. Should be max 2 hrs physical work, and prob another hour on site firing it back up and demonstrating / commissions the system before they depart. Re a good fitter near you, that’s simply down to legwork, so get the legs moving . You’re over 5 hrs from me, so I’d be crazy expensive if I called out, so get on the phone and keep ringing around, but if you keep drawing a blank PM me and I’ll see if I know someone nearer you. When you / they drain down, you need to be sure they don’t introduce air into the loops, so don’t choose a nugget or you may inherit issues from their ineptness.

Not exactly life or death tbf? And it’s not caused an issue to date… It’s upside down, pumping the water down instead of up, which gripes me as much as that cable gripes you, however the effects of having the pump ‘the wrong way around’ are more consequential, air wants to sit in the pump, when low flow rates cannot purge the air downwards when fighting over it wanting to rise upwards. The air does rise and settle when the pump is off, but sits there without an automatic air vent to let it out, which is why I always bin the manual vents and fit 3rd party AAV’s eg so these do a bit of self maintenance/bleeding. Doubt bleeding the pump is an issue, more the fact it is in a constant battle trying to pull any trapped air downwards, through, and out; it can then only be released by being pushed through the loops to get back to the highest part of the manifold, where the whole damn cycle started again! Get some AAV’s fitted asap here plz!! @MorganP 3 lpm flow rate on the 12mm pipe is not too shabby tbh, and if the pump was zooted you’d not even have that. How old is the pump? Is it noisy? We need air vents fitted as the first steps in the process of elimination, before changing anything more (imo).

I’m coming to your house and I’m confiscating all of your foil.

Carry on then squire. “so B it” lol.

Mortar at the sides is pretty much cosmetic, the RSJ is doing the work here The structural engineer would have stated how / if any connection was detailed, so best to see that first, and let us know, vs just assume there’s anything wrong here.

My PH design guy says 1000mm apart is absolutely fine, and that is fortified in my opinion when you see combination vents doing both the 'inny' and the 'outy'. No need for 2m afaic, and I have fitted a lot of MVHR systems successfully in the last decade+ with excellent results and feedback from clients who have then moved in and are living with the systems.

A semi-dry concrete mix, with 10mm aggregate, should be fine, and won't self-level. You can lay this good enough to take the micro-cement, if you take your time and do a good job of levelling off the surface with a straight edge (like a spirit level for eg). Once the concrete has been left a good few hours it can be 'blocked' to further improve the surface finish, by rubbing it over with a common brick (like a coarse sanding block). Plenty of fast-setting cement products out there such as Ardex A38 etc, but the details from the MC manufacturer will dictate when you can lay/apply it. The semi-dry concrete mix will have far less water, so would be the fastest 'drying' solution imho.

No issues there afaic. The foam's just been used instead of mortar to close the gaps, I assume to get your friend weather/vermin tight. The RSJ will likely now get nogged out with timbers, faces with OSB3 with Expamet, and get rendered to complete the job. Usual detail would then be to have the web filled with rockwool on the interior; a decent builder would add some EPS to the external web and foam that in for a bit of finesse, but not really critical as the external steel and brickwork are 'equally cold' and don't contact the internal leaf.

No, it doesn't. If the invert (drop from one end to the other) is <1300mm then you don't even need and AAV (air admittance valve, aka a "Durgo"), so all I would do is make the 90 bend an inspection bend LINK so you can rod down the 8-9m run, and back into the 1m run for self-maintenance.

Just fitted 2 of these, but they're expensive, yes, but very good build quality; both acoustically and thermally insulated so no need to insulate externally which is a wonderful thing when you're working in the worlds smallest / most awkward plant space!

I don't have a preference here, so-to-speak, as it needs to be compliant. Plan B is kosher, just I'd be doing everything I could to not have an IC inside my house. But it's a cabin, and you are where you are, so in reality, as long as you buy a proper screwed gas/water-tight lid IC, then carry on!

Just run all the taps for 10 mins, which will introduce fresh, slightly chlorinated water in from the mains, and should be suffice. You may see some initial discolouration of the water but nothing too bad, as most ‘vans are plumbed in plastic (push fit) so near zero corrosion etc.

You fell for the trap, lol. 😜

Not even had my second coffee yet, but there’s a lot to take in there. Great thread, as this often comes up here / there sporadically, so it will be very helpful to have replies in one place, thanks; going to make things easier for visitors and members who come and search the forum. 👍

Doing some carpentry, firing airtightness membranes, and fitting MVHR of course lol. Slight bit of plumbing involved too The BCO needs to have input here, and if they are pragmatic they’ll just ask for rodding access at the WC, or at worst the OP will need to carry that run on to outside and fit a rodding plate at the level of the hard standing. Usually, from the external chamber, the rules say a straight run with clear line of sight to the rest bend rising to any WC, or any that involve solids (such as a kitchen sink). As there’s a Y branch, then a 135° bend, then the rising rest bend at the WC, you cannot rod to that rest bend from outside, are there’s the issue with this arrangement. If the Y branch + 135 + rest bend can rise in the corner of the room, boxed in, and there’s a T branch there that has a rodding eye / cap in the top, and then the branch runs horizontally to pick up the WC, that would suffice. No need for a stub stack and an AAV, as the inverts don’t make air admittance an issue here; that means the boxing in can all be low level. What happens to the pipe at the end of the run? Just collecting a basin, and then going up to roof level to function as an SVP. If so, any possible air admittance is provided there, but could also be done with an anti-siphon basin trap, if the BCO insists on it only!

Lol. I’m in the trenches, so to speak, at the moment. I’m not shy of anything, as no job is beneath anyone, afaic. 😉

The CT clamps usually have an arrow under the bottom of the clamp body, but these have sometimes been put in arse-backwards in the factory, so that’s the first place we look if such an issue exists. Your installer may be correct, that the clamps are installed as per the direction shown, but you need to reverse them to see if that rectifies any possible issue. You’d try reversing L1 for a trial run of say 24hrs, then put it back as installed and then go to L2, and so on. VERY important you don’t lose track of where they are atm and which direction they currently face; you can mark these with Tippex or such to help out.

Usually you can just about get a pound coin in between panels, so at nearly an inch it sounds like a big gap. In roof or on roof? You can space uniquely on rails but not with trays.

May just need counter battening as well as fundamental battens atop the sarking, to increase the air gap / flow.

I doubt there’s much point in attempting to make the 2 circuits independent, as the TRV’s will provide simple, effective control to each space with a radiator, whilst the system ticks over to the UFH in the background; so basically your entire heating system is ‘on or off’. The issue is, if you have a room stat downstairs there is a risk of that switching the heating off sporadically, starving the rads of flow and the sections of heat input. Theres a lot of info to be exchanged for us to fully grasp / offer a robust solution, but as above, get these guys back and make it their problem. The caveat is, they may be at max capability already, hence the crappy solution they left you with, so you may need to escalate this if they can’t step up to the plate.

The quickest route is to just add a TMV and pump to the UFH manifold, and raise the CH flow temp of the ASHP. I doubt you have enough wiggle room to just slow the UFH flow rates down, but it is a possibility; but then you’d need to dial the CH flow temp up by max 2-3° to see if the rads perk up a bit. This will be quite coarse, and as TRV’s operate the balance will shift as it’s all hydraulically interconnected; water flow will just go to the path of least resistance, so that’ll prob be the shortest UFH loop or the first rad that it ‘sees’. Ultimately, I think it’s time you called the installers back, sit them down, and lay all this out in front of them, as atm you’ve not got a system fit for purpose and a wedge missing from your bank account for the (dis)pleasure.