Motorised valve to shut off part of heating system?

I have a hair brained idea. I don't want all our heat to go into our conservatory when we're not using it.
Use is normally predictable, because we use it as a dining room. Heating system is fairly standard, and conservatory rads are just extended off main house heating circuit,
Can I put a motorised valve at the flow into the conservatory, and attach it to a timer (plug-in or otherwise) to let the water through only when it's in use?
This is all new to me. I assume something like this would do it ("normally open" version)... http://www.honeywelluk.com/Products/Valves/Motorised-Valves/V4043-Motorised-Valves / ...but the reference guide says "Note: Continuous operation of the valve motor at the fully open position is not recommended." What do they mean by continuous - seconds, minutes, hours, days?
I was going to hide this in a box on the wall in the conservatory which can be easily opened when it breaks down. Otherwise it would be under the floorboards under laminate flooring which would be a real pain!
Would this work? Any model particularly suited to this (i.e. simply use with a simple timer)?
Cheers, David.
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David Robinson submitted this idea :

Why, when your use of the area (and need for heat) will be very limited use a normal open/ powered to close?

http://www.honeywelluk.com/Products/Valves/Motorised-Valves/V4043-Motorised-Valves /
I would assume they are refering to the normally closed version. I think what they have in mind is continuos cycling to control the temperature in a zone. Your use will be on for an hour(s) then off, rather than intermitant cycling.
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On 04/11/10 17:45, David Robinson wrote:

The easiest way would be to put programmable TRVs on the radiators - e.g. :-
http://www.screwfix.com/prods/71054/Plumbing/Radiator-Valves/Terrier-i-temp-i30-Programmable-Thermostatic-Radiator-Valve
Cheers,
Colin.
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Indeed, and Lidl have the Honeywell variety for £20 at the moment. The built-in frost setting could be useful (at least whilst the rest of the heating circuit is on).
Mathew
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Thanks, that looks far easier. Well, easier to install. Probably means no one will ever figure out how to use them, and they'll get prodded to destruction whenever I'm not around and it's too hot or too cold!
Cheers, David.
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On Thu, 4 Nov 2010 10:45:43 -0700 (PDT), David Robinson wrote:

Why use a normally open? Surely the use of the conservatory when you want heat is much less than the unused time. Normally closed would be better and the time switch to open it as required. Of course without a link back to the boiler/pump there won't be any actual heating of the conservatory unless the heating for the rest of the house is on. That may or may not be a problem.
Do you need to think about frost protection, maybe a time switch with a frost stat across it? But again without any connection back to the pump this won't be proper frost protection. This only needs a connection back to the pump as circulating the relatively warm water from the house even without the boiler on will keep frost out of the coservatory.

Wise though they are pretty reliable devices.
--
Cheers
Dave.




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wrote:

Yes, that's what I meant to type! Mind was running ahead to the next concern...

...thinking whether "normally open" would solve that problem. If it is a problem. I can't see how a valve which can't be energised for hours at the fully open position would be much use in a heating system, unless I'm missing something, so I was concerned about that statement (and my lack of understanding!).

I don't think it would be a _problem_, but I was trying to think through whether it would make any sense (and be possible) to add a thermostat in the conservatory and to somehow "AND" this+conservatory timer with the house thermostat - so the heating kicked on when either the main timer + house thermostat were on, or when the conservatory timer + conservatory thermostat were on.
Of course that would mean that the conservatory bit will cause the whole house to be heated when not really wanted (though there are TRVs throughout, so it won't go mad). It's not that easy to split the conservatory into a proper separate zone. Possible, but quite a pain. So options seem to be:
1. have conservatory as just extension of main system (trivial) 2. have conservatory as proper separate zone (painful) 3. put valve controlled by timer in conservatory 4. put valve controlled by timer + thermostat in conservatory (pointless - conservatory rads already have TRVs) 5. put valve controlled by timer + thermostat in conservatory and feed back to main control unit to allow it to run boiler + pump even when main house thermostat is off
There's a cost/hassle/benefit trade-off that I really can't think through.

I don't know. There's switchable frost protection on the main house thermostat. TBH if we go away during the winter, we just turn the thermostat down but leave the heating on. I guess an option to open the conservatory valve during frost would stop it blocking the frost protection.
Cheers, David.
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David Robinson wrote:

I expect what they mean by "continuous" is just constant on, as in 24/7. The motor (which opens the valve) is stronger than the spring (which shuts it). If the valve is going to be left in one position for months without moving, it may get stuck. Not a lot, but a little. Probably so little that the motor would shift it, but the spring might not.
"Non-continuous" operation basically means the valve is being wiggled often enough (even if only once or twice a day) that it doesn't get sticky enough to defeat the spring.
I don't think "continuous operation" has anything to do with worrying about the motor overheating - after all, the whole valve unit is going to get pretty hot anyway.
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Ronald Raygun wrote:

my UFH motorised valve burnt out after a few months of 24x7 on..before I fitted a proper master stat.
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wrote:
I've been thinking about this option...

...does anyone know if it's possible, and how I'd wire it?
I might be able to figure it out with a bit more head scratching. I seem to have an S-plan system - anyone got a clear circuit diagram I can compare it with?
Thought there was one in the FAQ, but can't seem to find it now.
TIA.
Cheers, David.
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<http://wiki.diyfaq.org.uk/index.php?title Ξntral_Heating_Controls_and_Zoning#Multiple_heating_zones:_S_Plus-plan>
with all the wiring and plumbing diagrams here.
http://www.diyfaq.org.uk/docs/Sundial%20Pipework%20Schemas%201st%20Edition.pdf http://www.diyfaq.org.uk/docs/Sundial-Wiring-Rev1d-2nd%20Edition.pdf
--
Adam



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wrote:

Thanks Adam.
OK, what I want to try to do is this:
http://www.mediafire.com/i/?7yov0c6tzvu4x9x http://www.mediafire.com/i/?s5drpm7c5v9kj8q
So: 1. The valve will only let the flow into the conservatory rads when the conservatory timer is on 2. When the conservatory timer is on _and_ the conservatory thermostat is on, this will switch on the main heating valve, which will switch on the pump and boiler. (This way a low temperature in the conservatory can switch on the heating, even if the temperature in the house pushes the house thermostat off. I'm relying on the TRVs in the house to stop it getting too hot).
I'm concerned that pushing an extra live into terminal 5 on the connection block will send live back into the house thermostat, and then into the house time controller. Can't see why it should matter, but maybe I'm missing something.
Will it work? Will it electrocute someone? Will the main house thermostat or timer blow up when live is fed in to the "wrong" side of a switch?
Cheers, David.
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Your conservatory room stat should feed the new valve with the valve controlling the signal to terminal 5. In your diagram if the house programmer and stat are calling for heat at the same time as the conservatory programmer then the conservatory thermostat by passed.

If I was wiring a frost stat into the system it would go between terminals 1 and 5 on the wiring centre. So you are perfectly safe electrically.
If you can get wires from the conservatory to the boiler why can't you run some microbore back and have a proper zone for the conservatory?
--
Adam



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wrote:

I was going to have the conservatory thermostat set quite low - I only wanted it kicking in if it got rather chilly. The rest of the time, it'll just get heated when the rest of the house heating is on and the conservatory valve is open. But now you've got me thinking about doing the job properly...

Great, thanks.

I hadn't thought of microbore (will that work T'd off an existing system?), but the problem is more getting the pipes from the airing cupboard (where the pump and existing valves are) to the nearest wall I could drop them down. There's just too much clutter (pipes, cables) in the space under the airing cupboard, and so much hacking of the joists that I daren't cut any more wood away. Still, another 20mm hole couldn't hurt, could it? ;-)
If I use normal 15mm speedfit, can I run the flow from a new valve in the airing cupboard, but just connect to the return at the nearest existing radiator to the conservatory? Running one new pipe instead of two would mean less hacking around near the airing cupboard.
Cheers, David.
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Yes, microbore would be fine.

You already have a return at the conservatory radiator. I am not sure how good it would be to use this in practice, but if the run is not excessive I see no reason why you cannot use it.
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Adam



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