Mixing valves for UFH

See. He is a professional wanker.

Who are you on about? I'm a man of leisure so can't be professional. Or do you mean the NG's favourte correspondent?

Toby.

No cude is the word.

The reason for this "over-engineering" as you perceive, is to create superior comfort levels. UFH is notorious for discomfort.

You refer to upper suspended floors. British homes are notorious for the slap building. The joist will invariably not be sealed where it enters the inner wall leaf. Then you loose heat to the cavity. the pipes should be touching the boards above for maximum heat transfer.

UFH pipes should not be fitted in a ground floor vented space unless the correct suspended floor underfloor plates are fitted with appropriate insulation, as you will be also be heating the street.

Not with the crude control you have. having UFH zoned means you can have electric blending valves that lower and raise the floors temps.

As I have said. Get is "zoned" correctly with adequate control on each zone.

I find that hard to believe.

That is roughly the case with all UFH

If you want a simple UFH system, zone it using a manifold, or make a manifold yourself. A manifold means all controls and adjusters are in one place. The zones cold be one front and back on the ground floors and the same on the 1st. Have one pump for the whole system and a zone valve on each zone operated via a room stat. Then have a condensing boiler with a DHW mode that ramps the boiler temp to full when DHW is called. Have a DHW priority system with quick recovery cylinder. Have the CH side of the condensing boiler set between 40-50C. No blender required and economic condensing boiler performance. If not a condensing boiler then have a blending valve and the boiler set to 80C, as you don't want condensing occurring in the boiler.

Ensure that insulation is under UFH heating pipes in suspended floors. In upstairs floors make sure the insulation is high density mineral wool as this will reduce sound a hell of a lot, so killing two birds with one stone. Having no insulation will mean you may be heating the ceiling beneath as above there is wood and laminate or carpet acting as a greater barrier to heat passing to the rooms above than the thin plaster board beneath the pipes.

"Always" have plastic barrier pipe under solid floors.

The above is for a "basic" UFH system. Ideally you would want the floor temp to modulate to demand (this usually means having a pump per zone) and as a real bonus anticipate the coming temp rise or fall by having outside weather compensation. A good zoned heating system can actually take solar gained heat from the south side of a house and distribute it to the north side.

Many people have been bitterly disappointed with UFH because the response rate is so slow meaning occasionally they will be too cold or too hot until the system catches up.

I seriously suggest to take on board much of what I have said.

As you having a new floor then go for it, but make sure you have more insulation under the floor than what the floorer will install. This will have a two way benefit of less heat loss for the pipes, and less to the ground beneath overall.

You might want to keep the existing rad in place until you are satisfied the UFH work OK, the remove it. Pressurise the pex pipe before the screed is laid. This can be with mains water as a temp measure until you have it connected to the mains system.

Put as much insulation as you can, I think you are doing that. What you should do is make a "tray" of insulation, as this will prevent heat escaping to the ground and walls via the sides of the concrete floor. Rise up the walls with insulation and screed to the top level of the side insulation, then the floor finish can be laid over. So when the screed is laid you will see insulation at the same level all around the edges. Easy to do.

Should be fine.

Thanks for the suggestion, may get drain test bungs hired at the same time as that. I've two jobs that can be done together. More good news, got a Wilo 50 pump today £17.50inc vat because the box was torn - go figure. Still unconvinced on how fancy a mixing valve to get.

Toby.

Never go more than what the makers say.

I think he means you.

Trusting fool.

F*ck off, Noddy..