Idea for a cheap simple wet UFH layout & control system?

I wonder if anyone can advise me on some questions that I cannot find mentioned anywhere on the web for an simple wet UFH project.

I have just laid a 7-loop underfloor heating pipe system in my (very well insulated) small 3 floored 3 bed family Victorian house.

I intend to use a combi-condensing boiler, and run the boiler flow heating pipe first to two directly in-line conventional radiators. Then return th= at flow to the input manifold for the 4 underfloor heating loops for the wooden upper floors. (FYI =96 I have used old thin aluminium offset printin= g plates as spreader plates wrapped around the pipes!)

The upper floors' return manifold will then go to the input manifold of the= =20 concrete ground floor 3 heating loops. This ground floor return manifold will then return to back to the boiler!

I figure the radiators will initially lower the water temperature down for the wooden floor input manifold. Then this lowered return water will go into the concrete floor input manifold, which will then return to the boiler at a very cool temperature. Thus making a very efficient condensing system! (If not very tepid)

To save costs (and as an experiment!) am intending to construct the two set= s of manifolds with 22mm push-fit copper tee pipes (with 15mm reducers) and loca= te it under the ground floor staircase in cupboard, about 4m from the boile= r using 22mm insulated copper pipes.

I will balance each loop with gate valves (or any ideas?) on the return manifolds, using temporary temperature gauges clamped onto each retu= rn pipe to get even return temps. I will put stopcocks on the input valves = for isolation purposes.

I intend to only use the in-built boiler pump to circulate the heating, and use the in-built boiler water temperature thermostat and timer to control the room heating temperature.

I can will make allowances to retro- fit TRVs in each room if the room on t= he upper floor loops only If heating is uneven. But I intend to have the he= ating on in all rooms constantly from November to April

Q.1. Do I need to put in any Automatic Airbleed Valves on the upper storey loops, (If so where should the AAV be positioned -Just before the return pi= pe goes vertically down to the manifold to catch the air?)Or does the UFH w= ater have enough pressure force the bubbles down to the ground floor manifo= ld AAVs.

Q.2. Do I put AAV=92s on BOTH the inlet AND return manifolds, or just retur= ns?

Q3. Is this idea workable? If so can anyone recommend a decent boiler with = a tough enough pump!?

Reply to
Mick
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Might work well enough to get away with but if you do fit TRVs to any of the rads that'll upset the balance of the system so I'd suspect it wouldn't work too well in practice. But by all means have a play and see if it's good enough to get away with.

Speedfit is your friend. Cuprofit etc are just poncy versions which may look better (eye of the beholder) but probably more expensive and harder to demount if/when you want to play around.

Gate valves are good for balancing, lever valves good for isolation.

The inefficiency inherent in having rads blasting away hotter than necessary in order to keep your UFH running well could negate any improvements in economy and comfort from having UFH and your desired low return temps.

That's a separate issue. If you have rads at the top of the system you can bleed from them, but any high points in pipework may need bleed valves - automatic or otherwise.

Shouldn't be any more demanding on the pump than a conventional system. I like Worcester Bosch boilers.

I suggest you look at the wiki articles on UFH and also check out my article on it on

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for an example of a DIY-able low-cost manifold. Personally I'd go straight for that sort of system for your UFH. You may find you need different temperatures for the screed-laid parts of the system and those using spreader plates so don't try to run them all off one TMV+pump setup (or knock it up with Speedfit so you can change it around again easily).

Reply to
YAPH

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