DIYbanter - pressure reducing valve to balance up/downstairs h/w flow

Jim Walsh
wibbled on Wednesday 30 December 2009 13:12

Dear all, I have a combi boiler in my house. The tendency for the flow
rate in the shower upstairs to be be reduced when a hot tap is turned
on downstairs really bothers me. Presumably, the water is
preferentially drawn by the downstairs water outlets because of the
pressure differential. So, am I correct in thinking that a sensible
solution is to fit a pressure reducing valve to the downstairs hot
water supply to the taps in order to balance the resistance to flow of
up and downstairs? Obviously the flow rate in the shower would still
reduce when a downstairs tap is turned on, but am I correct in
thinking that the effect should be less marked?

Thanks, Jim.

Unless you have stupidly low mains pressure, I suspect it is more likely it
is the resistance of your plumbing giving preference to the downstairs tap
(being closer to the combi perhaps) and the height difference isn't helping.

How powerful is the combi for HW out of interest?

So another option: you could go one simpler and fit a flow reducing valve
like:

http://www.bes.co.uk/product/99~PL~1...egulator-Ball-
Valves.html

(Item 17527)

The end result will be the same - reduced flow to the taps, but these might
be cheaper and give more reliable long term service compared to a pressure
regulator.

I find mains pressure on sink/basin taps can cause excessive and splashy
flow anyway. With a pair of those valves per sink, you can play with the
flow rate by changing an 86p insert which can be fitted without turning
anything off except for the valve itself, which also acts as a good quality
isolation valve.

You might consider starting with 4 or 6l/min for small basins, 6-8 for a
kitchen sink. Personally I'd buy a pair of each size and play until things
work better.

Just an idea.

--
Tim Watts

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