Flow Rate problems for combi

[tnarg999]

We want to upgrade our boiler to a combi as our Potterton Netaheat will soon expire permanently...

Brit Gas came and quoted but said our flow rate was 8-9 Ltrs/Min which would give poor performance on a combi.

I contacted the water board to see what the flow rate was at the stop cock in the road. When they came out they couldn't test it as when the house was built too much concrete was put into the road fitting. Waterboard came back, dug up road and replaced the road stop cock, so now there is a nice and easy plastic dial to isolate the house ready to accept a water meter. They said that there was 25Ltrs/min at the road and 15ltr/min on our outside tap.

Apparently this still isn't enough to avoid the "cold flush" when using a shower off the combi. We have 22mm plastic poly pipe entering the house from the road stop cock into our stop cock.

Anyone got any ideas on how I can increase the flow rate without digging up the garden to see if the plastic pipe is kinked..

Thanks!

 

[ChrisR]

First put your garden and cold kitchen sink taps on full and add the amounts, to see if your g tap is restricitve.

Also phone W board to find out what your pressure s likely to be.

Is the old buried stop cock still in the line or do you have a new pipe going past it?

 

[tnarg999]

Chris R,

We get better flow on the garden tap than the kitchen sink, but I think that is because the kitchen tap is restrictive disc valve of the IKEA variety.

Waterboard tested neighbour who gets 22ltr/min on their outside tap, (btw both mine & neighbours outside taps are spurred off the kitchen sink)

Water into the property comes via our own stop cock in the garage with blue plastic tube from road supply. Garage stop cock has a tap on it - so you can test the flow. This has 15 ltr/min. Would it make a difference if I changed this stop cock? Someone said there may be restrictive washers in it..??

Water board replaced their old road stop cock completely (I think..) as the flow rate did improve on the garden tap from 9ltrs when BGas tested it to 15 after water board dug up road tap.

I am thinking the possible reasons why we have 25Ltrs in the road and only 15 at the house are:

1. Leak or kink in the poly tube from road
2. Internal Stop cock restricting flow in garage
3. Waterboard fitted new road stop cock after knackered one.

Thanks for your advice