dpmiller

why do you say that? 2 pipes and a couple of wires. No need for any accreditation or fancy signoff.

if it's a loose nut, you'd be best with a rubber washer

sounds like there's air in the system, tbh.

I wonder what the outside temp was last night- perhaps the anti-freezing setpoint was reached?

and it won't be at full chat all 8 hours.

try this: https://www.schiedel.com/uk/products/additional-ranges/protect-box/ we've used Ignis Protect to go out through out timber frame

I'd be more worried about pressure blowing out the H/E, they thin out over time...

we know that the Mfr's controllers tend to be pretty sh*t too, whether Vaillant, Carrier, Samsung/ whatever. @ProDave is using good old-fashioned "heat for me now" control. Time to stick a simple stat in series with the stoopid programmer...

but you could use either with copper...

you do remember the TS has a heat exchanger in it? So the output temp varies with flow rate, and the body of water is cooled as the cold water flows through the coil. /BTW I've fitted one, and I'll be using an ASHP. Convention be damned..

almost... as others have pointed out in the past, the store temp of a TS drops as you draw off, so it's hard to say what capacity you actually have. With a normal cylinder, if it's all hot, it all comes out hot.

you draw from a hot tank at whatever temp the tank is at. With a TS it's a heat exchanger and the flow temp will be lower than the stored temp. you need sufficient overhead to cover this...

there's a lot of crap in that pump.

finding the right instructions would be a help...

/what size is the expansion vessel? Is it new too?

because they installed the whole system.

blocked drain valve? Boiler full of scale/sludge?

That's a variable flow damper made out of foam and costing about a fiver?

^ as Dave mentioned, I'd be looking at the "supply" flow and return direction.

are the flow and return the right way round at the manifold?

Thanks all. Damp isn't ever going to be a problem anyway as the whole subfloor is poured on a Radon barrier and they're internal walls.

@PeterW 1400x900 trays. No I don't want flush with FFL. I'm aiming for 10mm or so above, but final finish isn't decided yet. Guessing 15mm will cover the final finish, which is likely to be tiles. So (say) 18mm plus a thick mortar bed or 25mm and a thin bed of tile adhesive will get me to the height I want I was thinking/ wondering more about how much movement there might be in the PIR rather than how the tray would be supported as such.

So I'm finally starting on the ground floor buildup. It's 50mm poured screed on 150mm insulation (100mm PIR/50mm graphite EPS). I'm unsure of how the tray works in this situation... The tray is (IIRC) about 45mm thick, so I'll need to set it on ply/OSB/cementboard to get the levels right. That bit's OK. But how does said underlayer sit on the PIR, is it just bonded down or should it extend under the screed edge too, to "key" it in? It's in a corner so two walls and two floor edges. ta

but that's more about the keel than the weight surely?

what does "fail safe" mean in this context?