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.

"Nis" wrote in message
oups.com...
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?

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.

In an earlier contribution to this discussion,
Nis wrote:

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.

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

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.

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
--
Andrew Sinclair http://www.smellycat.org

In an earlier contribution to this discussion,
Andrew Sinclair wrote:

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

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.
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.

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.
--
Cheers,
Roger
______
Please reply to newsgroup.
Reply address IS valid, but is disposable in the event of excessive
spam.

Roger Mills (aka Set Square) wrote:
In an earlier contribution to this discussion,
Nis wrote:

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.

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.

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

NT

In message , "Roger Mills (aka Set
Square)" writes
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.
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
--
Andrew Sinclair http://www.smellycat.org