I currently have a Y plan heating layout.
I'd like to connect the conservatory UFH to it. The UHF has a thermostatic valve in the return circuit and is situated some distance (in terms of pipework at least) from the boiler.
Is there any obvious alternative to converting from Y plan to S-plus plan (including a bypass for the boiler)? It's worth mentioning that the UHF and heating are never expected to be on simultaneously, though the system should be able to withstand it without damaging itself.
There are no obvious alternatives that I am aware of as a mid position valve is always "open" to at least one zone.
That's what I thought, but it's always worth picking a brain or two before starting (or in my case starting to think about planning to contemplate).
I can think of a way which *might* work - but you'd end up with a highly bastardised system which future generations (or even the present one!) might not be able to understand!
How about if you split the CH output from the 3-port valve into 2 circuits, with a 2-port zone valve in each - one for the radiators and one for the UFH. Control these valves a bit like in an S-Plan system, with the radiator one being controlled by the CH room stat and the UFH one being controlled by a new? roomstat[1] in the conservatory. Now the clever bit. . (I think!) Parallel the auxilliary contacts in the 2-port valves, and connect them into the circuit where the Y-Plan's roomstat used to be.
That should give you independent control of the radiator-based and UFH parts of the heating system, still with boiler interlock. However, you still might need a bypass if the boiler needs pump over-run because there would no longer be a guaranteed flow path.
[1] I assume that the UFH's thermostatic valve is mechanical rather than electrical, otherwise you might be able to use that instead of an additional room stat. If it *isn't* being used - either by my 'solution' or if you go the full S+ Plan route, it's probably best got rid of.
Yeah - I thought of that, but in the end I think it'll be easier to redo it as S-plus.
Thanks.
When I fitted my current boiler 18 years ago my supplier didn't have any 2 port valves in stock, so I opted for 2 3 port valves instead of 3 2 port valves. Upstairs CH, downstairs CH and HW. It worked, but certainly was non-standard. I could figure it out but J. Plumber probably couldn't. I put circuit on lid of wiring centre.
The 3 port valves, particularly the one on the heating zones, proved to be unreliable (the micro switches failed, I had a spare head and changed one about every 6 months. After about 3 years I replaced the heating zone one with two 2 port valves wired as above. These worked well until about 3 years ago, when small leaks developed around the stem of the water part. The hot water valve had been modified to be a divertor, losing the mid position, when I replaced the first 3 port valve with 2 port valves. In this mode it was reliable. Over the last 3 years all valves have been replaced resulting in an almost standard s+ plan, modified to give hot water priority using back contacts of HW thermostat and timer. This is reliable.
Boiler had bypass, pump run on not needed, but I added an external bypass at a lower setting which is adequate and quieter.
Don't (yet) have such beast, UFH is contemplated for kitchen and dining room. I'll probably wait until the current boiler (18YO gloworm fuelsaver complheat system boiler) is replaced by a condensing one once I can no longer fix it.
YMYA. Ours is a Glow-worm Fuelsaver MkII and still running nicely.
Have something to add? Share your thoughts — no account required.
Ask the community — no account required