How to increase water pressure from Valliant combi boiler.

[JonnyCT]

Hi.
I've recently bought a house which has a Valliant combi boiler (ecoTEC pro 28 R2) which, according to the label, was installed in 2010.
I'm now in the process of creating a small shower/wet room but want to be able to make the most of it, by having good water pressure in it.
Currently the water pressure in the house is quite poor (about 1.5 bar).
My plumber suggested he change the existing 15mm pipework going from the supply pipe (in the cellar) up into the boiler. This was done yesterday, but has had very little effect. I spoke to Thames Water today about upgrading the supply pipe (which is made of lead and fairly narrow) but I think this will be very expensive to do (they will charge £500 just to reconnect any new supply pipe that was laid!)
My plumber has now suggested that he could put a large tank and pump in the attic to supply the boiler, but after ringing Valliant today, they say that this is not possible on the boiler I have (although their technical help desk didn't sound very technical, so I don't necessarily want to take their word for it).
Does anybody have any good ideas that would give me much better water pressure (without having to completely resort to throwing away the relatively new boiler and starting again?)
Thanks.

 

[Boilerman2]

If there is only 1.5Bar pressure no amount of pipe up-sizing will have any effect, you would be better fitting a whole house booster pump to the main in the cellar

 

[JonnyCT]

Hi. Thanks for your response.
I'm not familiar which such a pump (only pumps associated with a tank in the loft). Could you tell me how a pump in the cellar would work, or where I could get more information about such a thing? Thanks.

 

[ALEC1]

ifs a bigger main you need right back to the main in the street..., especially if there was no improvement in flow....if 10l/m is going into the house then no internal improvement will increase that!

It costs what it costs but will be issue free...pumps can break, are noisy and the tank takes up space..

Kemac can do it with a boring machine...

 

[Tibbot]

1.5bar is more than enough to ensure your boiler delivers its maximum flow rate. If you had greater pressure available you'd only have to strangle it down so your flow doesn't exceed what the heat exchanger can cope with.