Combi Boiler - Poor Flow Rate, Accumulator the answer

[jonVERVE]

I have recently fitted a boiler for a customer.

Having previously checked all the pressures and flow rates in the house i went ahead and ripped out their old tanks and fitted a combi.

Now when they flush a toilet or have the washing machine running water stops at the taps, i measured the pressure and its at 2 bar standing.

I have changed to main stop cock for a quarter turn leaver valve this improved the flow a little bit but still not adequate enough.

They don't want to put a bigger Supply pipe in so have been asking around and have heard about a water accumulator tank, never worked on one before so was wondering if anyone on heard could shed any light as to how one of these would help.

thanks

J

 

[doitall]

So what was the flow rate then and now.

And the standing pressure is a pointless number.

Your best plan would be to put the cylinder and tanks back, and just use the combi for the kitchen sink,

 

[mysteryman]

An accumulator may help, but this may cost more than sorting out the main - which should have been checked first! Your changed stoptap may be illegal.

 

[dcawkwell]

Yes an accumulator tank will sort the problem out.

Put in a non return valve at the stop cock and an accumulator tank
anywhere in the house that is suitable. Size of the accumulator
tank depends on the current flow rate from the mains
and how much demand there is over what time is required.

 

[Agile]

Are you Gas Safe registered?

Dont you measure the dynamic flow rate before even thinking of a combi?

Tony

 

[jonVERVE]

Yes i am gas safe registered,

it just so happens that i installed a combi in the house next door without a problem, so being in a rush as this needed to be done quickly i did not measure thinking there should not be much difference between two houses either side of a drive way.

turns out to my surprise the builders moved the stop cock when carrying out some work, and have extended the mains from the back of the house to the middle of the house in 15mm copper.

 

[Agile]

The problem is that you are meant to be the expert and to install a boiler which works properly.

That could mean that you have to pay for whatever is needed to correct the problem.

I would ALWAYS measure the dynamic flow rate before quoting as that can be a significant part of the cost to provide a good water supply.

Tony

 

[doitall]

Could also mean the pipe is damaged or leaking.