"Ed Sirett" wrote in message
news
On Wed, 01 Sep 2004 22:33:23 +0100, Andrew Beck wrote:

I think my house has a water flow rate problem and I'm looking for a
solution.

The house has a combi boiler and everything is run off the mains water.

The water flow rate from a single cold tap upstairs is about 10 l/min
The water flow rate from a single hot tap upstairs is about 8 l/min

The difference is probably due to the resistance of the combi boiler.

The problem is that if you turn on a cold tap the hot water flow rate
reduces.
If you turn on a hot and cold tap the flow rate is about 9.5 l/min from
the
cold and about 0.5 l/min from the hot.
The low flow rate of the hot causes the combi boiler to stop heating the
water due to inefficient flow rate.

Solution Ideas, will the work?

1) A pressure equalisation valve on the hot and cold water supplies?

2) replace the cold water supply pipe to the main pipe in the road as
the
input in to the house is only 15mm
Not really an option.

3) run the cold of a tank in the loft that is pumped?

4) run the cold and combi of a tank in the loft that is pumped?
Before the combi was installed by the previous owner there was a cold
water
tank in the loft.

5) Any others?

Before deciding what to do I would want to work out what the problem with
the mains is.

If the standing pressure is low then some sort of storage tank/pump will
be needed, or even reverting to a conventional system (no need to throw
the boiler out - just add the HW cisterns and cylinders).

If the standing pressure is 2bar+ then the problem really is the supply
and/or internal pipework.

You just might find that there is a stack of crap stuck in the mains pipe
work somewhere (on the stop cock most likely) whose removal will fix a lot
of things.

On a poor performing old mains pipe I once removed the house stop cock and
replaced it with a full bore one. I thought there might be a bock age in
the line, so inserted a large bore hose pipe on the new full bore stop cock.
Lead the hose to the garden and tuned on the water at the street. The crap
that came out !! I never measured it, however the water pressure was
excellent after.