Nickfromwales

And a thread where we should give a wide spectrum of information with the various pros / cons / caveats If someone is going to buy an UVC then we can advise on the best place to put it, and explain why. But, yes, cheap DHW would be an electric shower and a small multipoint, but when you add up all the electrics and the fact that an electric shower is a pile of shit on a good day, an UVC makes sense. Do the sums is my 2-Penney’s worth

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That is not correct. You need to provide heat metering that’s all

Do not put it outside! If you absolutely must, and I mean literally no other option is available, then look at a minimum of 300L capacity so you can lower the stored water temperature. That will massively reduce the standing losses from having the tank outside the heated envelope of the house. Temperature ( energy ) losses are amplified when the delta between two items is grater, eg tank at 70oC ( off immersion that is likely ) and ambient of 10oC or less will result in major heat loss and costs to replenish. Tank at 50oC in the same situation would have lower losses. Please put this inside !!

With regards to the pozi joists, has nobody ever doubled up on the joists ( sistered together ) to a) reduced hoist depth b) beef up the load capacity c) avoid steel / intermediate beams etc ? Seems a very simple solution which would also further reduce deflection.

Most decent 90o bends are 2x 45’s back to back in one piece.

Correct. That’s not a problem at all.

Yup. +1 50 in liquid will be ok, not great, but it’ll last and do what it’s supposed to. Floor will be just like a slow radiator at that thickness so no real issue. Will allow the heating to be ‘timed’ as it’ll respond quickly. A benefit in some folks eyes.

What score were you looking to achieve? Are you referring to trickle vents in the doors and windows?

Lol. I don't actually want you to have a fight ( honest )...... Well, maybe just a little one, and upload to YouTube?

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IIRC it's already fitted with a pump and TMV. I'm away until tomorrow PM, then I'll dig it out.

FIGHT!!!

How many ports do you need for the manifold? I'll dig that one I got out and post some pics of it. If it works for you it's yours for a pint.

Work out how much surplus you need to routinely dump and do the maths there. Pointless trying to dump a load of excess into a tiny ( 25L ) buffer. In honesty it’s rubbish as in the winter you’ll be lucky to see 25% PV output which will prob be enough to still be pulling from the grid most days ( so no surplus ). PV > heating = ?

Agree that 25mm will only be of benefit to affix the pipes with pipe staples. I’d bin the 25mm insulation and just use clip rails direct onto the slab, fixed down with a Spit nailer. Then sand and cement ( dry ) screed at 50mm thick.

Not put Willis heaters in upside down that’s for sure If I didn’t get bad luck, I wouldn’t have any. Yay.

Hence my comment on you asking where you can add another external heat source. It was general advice, sorry. Just texting between disasters atm so take with a pinch of salt ?

‘Twas a ticking time bomb my friend. This was just a crash that hadn’t yet happened, now it’s happened. “Simples” ( insert picture of smug looking rodent here ). The above arrangement does not lend itself to having any additional external heat source of any kind. This is a temporary rig only.

Electric combi boilers are crap. Stick with gas. Don't forget the costs of an enormous supply cable and possible fuse board ( CU ) upgrade to cope with the high current demand of the combi. If you have an electric solution for cooking, you'll also need to see if you have enough current coming into the house to cope. Bad idea.

These things are brazed shut, sealed units. The only access for viewing is through the pipe entries. These are just kettling as the water flow rate through them is way too low / slow when the TMV nears the target / set flow temp. Needs a second pump as per my Rolf Harris drawing, and then you'll be fine.

Please tell me you have 2 x 20a switches not one 20a switch and the feeds to both heaters doubled up off the one supply?

You cannot do that. You'll have to alter it to have a pump and a recirculating loop. The heaters are kettling and overheating.

Are you running the Willis heaters through a constantly recirculating loop with its own pump? Then the UFH should be Teed into that loop for flow and return to the manifold pump? A bit like a figure of 8 with the two pumps remaining hydraulically separate from each other. If so, the pump speed of the Willis circuit is too low. Have you turned the 2 Willis heaters down on the internal stats? They should be set to no more than 45oC.