Boosting hot water pressure

[perkin5]

I raised this subject a couple of days ago as a guest but was asked to register so now I have.
My problem is that I have a 4 storey house with an unvented hot water tank at the bottom of the house with a pressure limiting valve set at manufacturer recommended 2.1 bar. So at the top of the house the pressure is only about 1 bar with a flow of about 3 litres/min which gives a pretty poor shower, plus the fact that taps at lower levels can bring the flow to a halt.

The mains pressure is 3 bar but as this is anyway reduced to 2.1 bar in the HW tank, a pressure booster pump for the cold water feed will not help.

Is it possible to put some form of pump between the HW tank outflow and the HW taps to boost the pressure? If so what sort of pump should be fitted?

I should add that no way would any work be done other than by a qualified G3 fitter but I need to know enough to have a sensible conversation with him.

 

[Ch4 plumbing]

No you cannot put a pump on the hot, doing so would be dangerous.
Is the pressure reducing valve next to the cylinder? Or is where the water main enters the house?

 

[Chalked]

I think your problem is more lack of flow than pressure. Yes you will lose about a bar of pressure at the top floor, but it should still achive a good enough flow.
What make of cylinder do you have? As 2.1 bar msg be a tribune cylinder.
A whole house pump and a break tank will cure both.

 

[perkin5]

Thanks for that. The PRV is mounted next to the tank, which is an OSO Ho****er 170L. How does the PRV location affect the issue?

 

[perkin5]

Thanks, Chalked. The cylinder is an OSO Ho****er 170L and, on looking more carefully at the data label, it quotes the pressure as 3 bar. Might a professional recommend increasing the PRV setting from 2.1 bar to the full 3 bar or would he always want to play it safe by leaving the setting as it is at 2.1 bar? I'm thinking that an increase from 2.1 to 3 would be quite a significant boost in itself. By the way what is a tribune cylinder?

 

[Dotty]

It is an unvented cylinder. DO NOT TOUCH ANY OF THE CONTROLS!

DO NOT INSTALL A PUMP.

It is both illegal and dangerous for you to be messing about with it.

Stop now, follow this link...

[DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL]

And post a new thread with your rough location. You need a professional G3 qualified plumber in to look at the problem.

Job 38.11.