Poor Hot water flow from Worcester Greenstar Combi Boiler

[Pam50]

I have a Worcester Greenstar 30HE combi boiler.

I have tried to fit a new bath and found that the 22mm copper hot water pipe feeding it has a green sludge build-up inside it. I think this sludge and debris coming from it has caused the new tap, a ceramic disc type, to constantly drip.

I also find that the boiler can only supply enough hot water to feed one tap at a time, even though when fitted I told the supplier there were 3 bathrooms, one of which has a Aqualisa Quartz non-pumped shower.

I do not have either a cold storage tank or a hot water cylinder as all water feeds directly from the mains, via the boiler.

Can anyone suggest: -
a/ How do I clear the sludge from the pipes, and/or
b/ How do I increase the flow rate so that more than 1 hot tap can be fed at one time.

 

[tomy]

Most importantly did anyone check your mains pressure before fitting the Combi???? A combi is only ever going to be as good as your mains.

 

[Pam50]

Yes. Pressure in cold supply is fantastic and when/if boiler needs topped up, the pressure can easily exceed 2bar.
The only problem is with the hot water supplied to taps.

 

[Gasguru]

What Greenstar is it there are sveral models.

 

[ChrisR]

a Worcester Greenstar 30HE combi boiler.

Pressure and flow are different things.
Measure the total flow from all your cold taps when they are all open. Add them up. Hopefully say 18 litres/min or more ...?

 

[Gasguru]

A combi this size will only supply more than 1 tap if the flow rates are kept very low, however it may be worth checking the flow adjuster (on the cold water inlet to the boiler) is opened up sufficiently.

 

[Pam50]

We have checked as best as poss, and our flow rate appears to be around 28 ltr per min.

We have a 4 bed detached with 3 bathrooms and 16 radiators.

Have we been sold the wrong boiler?
How do we get a plentiful supply to more than 1 tap at a time?
And how do I stop a dripping tap? (Have already tried a different valve)

We changed from OFCH to GFCH a few years ago, just before gas prices in N.I. shot up. Seems that was a bad move too

 

[Gasguru]

The output for your boiler is 13.3 litre/min of hot water raised by 35 degrees. ie if the incoming cold water is 10 degrees and you want your bath water at 45 degrees you can fill it at a maximum of 13.3 litres a minute. Or two baths at 6.65 litres/min!

Did your installer not go through the pro's and con's of a combi?

Even the most powerful combis (normally available) will only provide 16 litres/min (storage combis a bit more for a limited time only)

A ceramic disc tap relies on two ceramic discs in very close contact with each other - if any debris has found its way between them or the contact pressure between them is reduced by debis they will drip.

I think you'll find oils now at 35 - 40p per litre.