JohnMo

Unless you couple that with a battery. Then low and slow wins.

That's a strange lunch your cooking up.

Here's a few things to read UFH-System-Design.pdf UFH output calculation.pdf

If they are quoting a buffer it isn't an expansion vessel. A buffer requires secondary pumps, a volumiser doesn't. A buffer provides hydraulic seperation and therefore needs a pump(s) for the heating circuit. Samsung Gen 7 schematic don't compel the use of a buffer, if your are doing an open system. They show a volumiser on the flow to heating circuit. Cylinder size is basically worked out as follows, 45L per bedroom, plus 40L. Reheat time assuming 300L and a 5kW output will be around 1hr and 20 mins to 50 degs, assuming bulk average temperature is about 30 degs.

Out of the parties that doesn't agree has the design flare? They are right. For me it's my wife, I have a say, then I'm told what going to happen. Simple.

Generally never required with sensible design. What size? Good. So basically the design should look something like this. Two floors if the same design flow temp no mixing should be needed. If one floor needs a higher flow temp some mixing may be required, this should be fine with an electronic mixer not a mechanical one. But if well insulated upstairs should really need much or any heating. So I would be tempted to flow a single flow temp to both floors and balance as needed with flow rates. So next is system capacity. You will need at least 20L per min kW output of the heat pump. If you don't comply with that add a volumiser on the return line prior to tee coming back from cylinder. Then run open loop from ASHP on weather compensation. Alarm bell - if you are bigger that 6kW, find a different installer. Alarm bell installer talks about a buffer, find a different installer. You want an efficient system you want a heat pump that modulates to at least half your heat loss at -3, then the heat pump ticks away all day at 7 Deg outside and maybe above that. Would suggest you heat loss is is in the 2.5 to 3kW range from what you have said. If so a 4kW would-be good.

Stops it floating away when you screed?

I just used PIR (70mm) didn't bother with the expansion strip. It purpose is to make up the expansion and contractions of the screed, as the UFH temperature cycles. A second (minimal) benefit is a small thermal break, to decouple the floor. I get the impression it's for retrofit applications where flow temps can be high.

Chocolate, new wallet to replace the one stolen in Paris, socks. I'm easy to please.

Yep, I'm in Scotland and the radio link is pants near us. I am the only one in location with a smart meter, that works and it's connected via 4G. Everyone else tried once and then gave in. 4G isn't an option until they have tried 3x doing everything else.

I wouldn't, OSB is vapour open. Do it correctly install vapour barrier, tape all joints, Use something like this https://passivehousesystems.co.uk/shop/adhesives-primers-sealants/fortax-6400/?utm_term=&utm_campaign=P-Max+Test&utm_source=adwords&utm_medium=ppc&hsa_acc=4901615203&hsa_cam=20355723828&hsa_grp=&hsa_ad=&hsa_src=x&hsa_tgt=&hsa_kw=&hsa_mt=&hsa_net=adwords&hsa_ver=3&gad_source=1&gad_campaignid=20364888406&gbraid=0AAAAApUFUNC26rUQyD2HwqFlOulMhVQWS&gclid=CjwKCAiAmKnKBhBrEiwAaqAnZ5CPWGBFVVio4GUfqzpKS1479NcoHwQrQVgTtExyEM110NUvopZ9HBoCl6AQAvD_BwE Only one chance to do it right - slow down a bit. You never know what's ahead of you, you maybe their longer than you think and wish you had done a proper job.

I had loads of trouble with signal, be a 'dog with a bone', keep calling them out to resolve the issue. It took 4 attempts before they got the correct kit in. They have to try 3x before they get permission install some better kit.

Are you sure - 23 is a lot of flow, nameplate says 13?

Could get 3 showers out of mine, you take the flow restrictor out, I never installed mine, because I always preheat with upstream preheat, can't do any better with UVC I now have.

That really depends on your starting point. There gets a point where return temp doesn't really get much lower, especially with WC when heating at 10 degs outside. Return temp can never drop below room ambient, even if it got to ambient, rads would be huge. So practically you are at min return temp already. Getting a bigger dT is just increasing flow temp for no reason. If you lowered your return temp any more, your 4 degrees delta for restart would never be reached or take too long.

I'll nip into town later and pickup some proper centre clamps. Will struggle to correct the LH side clamping zone. Some of the clamping zone will take some thinking about. Prevailing wind is directly on the front of the panels. Any wind from behind sails straight over the panels due to the hill.

We used copper. You don't with nails either.

Clamping areas are the same as the last panels they were ok in 80mph+ winds. Yes two strings to independent MPPTs.

Pretty flawed heat loss calculation you should have done it at -3 outside and 20 inside, but your boiler is still ok for that. Your just fooling yourself with overly small heat losses and too smaller range rating figure. Range rating to your calculations for heat losses at +5, what happens when you get a zero degree day, and your house drops to 11 degs? Because your boiler output is too low. Think I would rerun the heat loss calculation for realistic figures and range rated accordingly. First alarm bell is this. If you letting the house get cold (16 is cold in my book and that's your target temperature), the boiler needs to run balls out (especially when range rated right down), so may actually be struggling. Taking a long time to find a comfortable running point. To get a house to 16 with radiators in 2 hours is a long time. For me You have range rated too low You allow too much set back when heating is off - at a target of 16 why would you set back at all. Just let the heating run 24-7. Let everything stabilise. Your boiler will start to run more efficiently and modulate down on its own. Range rating is good for stop start heating as it allows a level of heating output more suited to the house at startup, but you have to careful, analogy If you are trying to fill a bucket with a hole in it (your heat loss), the hole allows 10L per minute to leak out. You open the tap (your boiler) and it flows at 10L per minute you will never fill the bucket. Open to 11L per minute it going to take a long time to fill. That is where you are now. Boiler running hard for too long.

Why not replicate the existing house with wood fibre IWI? Not a fan, too easy to make a dogs diner of it, and effectively make it useless. Disadvantage of IWI is you make the build thermally light, so temperature can yo-yo over a short time frame. It very limited thermal capacity. Or just go with a bigger cavity, heavy blocks inside and out, and either poly bead or mineral wool or similar cavity fill. Then just plaster, not sure what the parge cost brings to the party if your plaster anyway?

Me neither, every start equals wasted heat out the flue and stabilising metal work temperature, instead of real work heating the house. Long runs equal efficient use of gas.

You would drive down your pumping losses with a wider dT. But suspect they are low anyway. Your current mean temp is 29, the 40-28 drives your mean temp to 34, wouldn't you start to over heat the house quite quickly? To run 12 dT, and keep the same dT across the radiators wouldn't you be closer to 23 and 35? That would give an additional 3 degs of condensing and about as low as you could go. But whether you could actually get that low in practice is questionable, not sure you would ever get a permission to restart after a heat cycle, as return temp would never drop low enough. My Atag, with it's modulating pump and 32 flow would have been running 4-6 dT, like it or not.

Maybe simpler to do it upstream of the combi rather than after. Then small amounts of temp rise give massive uplift in flow rate. Combi-SuperFlow-White-Paper-v1-2-4.pdfCanetis-SuperFlow-Product-Sheet-WE-050318.pdf You can also do it way more cheaply than a mini store. As a mini store is based on heating medium in the cylinder and domestic water in the tubes. So you really need to connect the combi to system boiler for the proposed to work.

Why would you install with a gas combi? Tell us what you are trying to achieve?

Unistut copy from local electrical factors (Medlock), comes 6m lengths.