Accumulators or replacing water main

[cr0ft]

Hi all,

Got a customer I went to visit today who is keen to have a combi-boiler installed. Their static water pressure is 2.2 bars which is fine obviously. Dynamic drops to 1 bar which isn't so good, that's with 2 taps running. Flow rate is around 30 litres per minute.

I'm considering 2 options: -

1.) Dig up their front garden and run nice new 25mm mdpe pipe into the house, the stopcock is in the front cloakroom so not really a huge job. My labourer likes digging so it's a match made in heaven.
2.) Opt for a cold water accumulator in the loft, I presume these things come ready insulated inside? I've no experience of installing accumulators so wondered what people would go for. The customer has the occasional bath but that's it. Normally there are just 2 of them living there and they use showers.

A combi-storage boiler isn't really an option as it needs to be wall mounted and fit in a kitchen wall unit.

Any advice appreciated particularly with regard to option 2.

 

[hammers4spanner]

i wouldnt even consider option two keep a dry loft imho

 

[cr0ft]

OK brill. I noted when I was there that the stopcock outlet pipe is 15mm, so with this in mind is replacing the existing lead main with a 25mm MDPE main really going to make any difference to flow rate with this restriction?

 

[Howsie]

To take advantage of the increase flow through the 25 you'll need to address the bottleneck after the stopcock.

 

[mfgs]

All you will do with a larger main is increase flow, not affect pressure. I have seen combi's installed on much worse mains than that before and still work fine. I don't think those readings are too much of an issue personally and I'm not sure the gain would be worth the expense of either option.

 

[stevetheplumber]

same as above that sounds like ample pressure and flow for a combi

 

[Roger Welton]

Agreed, fine for combi, not so good for a unvented

 

[neily01]

Sounds like your have plenty of pressure and flow. If your installing a combi you won't benefit really from an accumulator.