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