Anti gravity valves

Hi all,

Currently when i set my back boiler controls to 'Hot water only', the radiators in the top half of the house (apart from the bathroom where the water cylinder is) come on. The radiators get warm very quickly - in a little over 20 minutes. However, the hot water takes 2 to 3 hours!!! and i reckon this is probably because the hot water is being diverted to the upstairs radiators.

I've read that an 'anti gravity valve' might prevent this problem (my system is gravity based). Would that be the best way to go, and do you reckon the hot water will then be available faster since the radiators won't be drawing it off?

Cheers.

Reply to
Nis
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Fit TRV to the radiators so they shut off (if not fitted already). In the summer the valves will be closed to no heat will be lost.

In my last house I fitted a 22mm flow valve (from Jayhard) in the in the back boiler space (you fit it in the CH circuit to prevent the CH circulating if the pump is off, I think, a long time ago it was....). I ended up removing it (compression fittings so quite easy) as the house was a lot colder until the heating switched on, as I missed the gentle background heat it provided upstairs.

Put the HW on earlier if worried.

Reply to
Ian_m

Assuming your CH is pumped, an anti-gravity valve would certainly stop the upstairs rads from getting hot by convection when the pump was off.

However, it may not make much difference to the time taken to heat a tankful of water. If you want to speed that up, the best way is to convert to a fully-pumped system and replace the hot tank with one which has a fast-recovery coil.

Reply to
Roger Mills (aka Set Square)

In message , "Roger Mills (aka Set Square)" writes

Ah ha! This might solve my problems too, since a mod to the pipe routing in our house the upstairs radiators suck all the heat out of the oil fired combi with the pump off with a detrimental effect on the time to deliver hot water - is there an 'official' name for an anti-gravity valve or is it simply a non-return valve. What would I call it if I were to search, say, Screwfix.

Cheers,

Andy

Reply to
Andrew Sinclair

I doubt whether Screwfix sell them - try a proper PM or heating engineer. It's not the same as a non-return valve, although it also has this effect.

A non-return valve allows flow in one direction only. An anti gravity valve has a weighted or spring-loaded flap which permits *no* flow in either direction when closed. It requires a certain amount of pressure to open it. This pressure is easily supplied by the pump but *not* by pure convection.

I don't understand your reference to the combi. If it *is* a combi, no heat should go to any radiators when it's supplying hot water to the taps.

Reply to
Roger Mills (aka Set Square)

If its a solid fuel burner, it must still permit gravity circulation when lectrickery fails.

NT

Reply to
meow2222

In message , "Roger Mills (aka Set Square)" writes

It has a thermal store of hot water (heating circuit water that is) to speed up the flow of hot water when there is a DHW demand. What I suspect is happening is that this heat is being convected out to the radiators through the return circuit (most noticeable in the summer when the bathroom towel rail is nice and hot without the aid of the central heating.

Thanks for the description of the anti gravity valve, I know exactly what you are talking about now.

Andy

Reply to
Andrew Sinclair

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