JohnMo

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.