Mend > Home Heating Systems

How to maintain the pressure from a combi boiler?

The hot water system in my house is supplied from a combi boiler, hot water on demand.
The system works good, but it is not possible to have a shower
and have any of the other tap outlets on or the cold water pressure falls.
What is the best way to maintain the water pressure to the shower and still be able to use the other water outlets ie turning on the washing machine or flushing the toilet

Robert Simpson Snr
August 2007

Heating, Home Heating Systems Boiler Pressure Hot Water

how do i repressure my boiler (vokera) after i have removed a radiator?

adam
December 2007

the simple answer is you can't.

thats why combis are only any good for small familys

a combi is not capable of running a shower and a ensuite at the same time.
a combi will deliver an average of 12 l/min at 35 degrees
run two showers at 12 l/min = 6 l/min each.

you can only take out what your mains cold will put in
so if you run one tap that will have good flow
run 3 cold taps then flow is reduced.

then end of the day combis are just a glorified water heater.

i meet loads of people that want a combi just to get rid of the copper cylinder and loft tanks to make room
but when you tell them they can't have their two bathrooms , washing machine etc running together they soon stick with a system boiler or a megaflow

you'll never beat a system boiler or if you want mains pressure at both hot / cold go for a megaflow system.

hi-spec plumbing
August 2007