Shower problem with Combi boiler

[BunnyW]

Hi All,

I have just had a Keston combi boiler installed to replace an older system which used a hot water cylinder and a cold water tank in the loft.

I have also had a Stuart Turner Flomate Mains Boost Extra pump installed in the mains water supply ahead of the boiler. The idea was that the pump would help with the problem associated with combi boilers - reduced pressure/low at one outlet when another outlet is turned on.

In this house, the shower is at the top of the 3-story house and is the last and uppermost outlet on the system.

I am finding that even with the Flomate running, all flow from the shower head ceases when the hot and cold basin taps are turned on.

Is this to be expected? Is there any way around this problem?

 

[Chalked]

Hi

What does the guy who installed it say.

 

[Last Plumber]

Hi All,

I have just had a Keston combi boiler installed to replace an older system which used a hot water cylinder and a cold water tank in the loft.

I have also had a Stuart Turner Flomate Mains Boost Extra pump installed in the mains water supply ahead of the boiler. The idea was that the pump would help with the problem associated with combi boilers - reduced pressure/low at one outlet when another outlet is turned on.

In this house, the shower is at the top of the 3-story house and is the last and uppermost outlet on the system.

I am finding that even with the Flomate running, all flow from the shower head ceases when the hot and cold basin taps are turned on.

Is this to be expected? Is there any way around this problem?

It's a combi and I think i'm right in saying the max you can pump direct from mains is 12 LPM ( I think that is without permission but you need to check with local water authority), so it will be like that. If thats how the pump is set up.

 

[SimonG]

What model boiler is it? What's the stated litres per minute of the boiler?

 

[SimonG]

Hang on.

Three storey house, combi boiler, how many bathroom?

 

[ShaunCorbs]

Yes or water lpm to half, sounds like wrong system also why did you install a keston boiler?

 

[Riley]

Would never help the situation. Boiler isn't designed for two outlets

 

[BunnyW]

Thanks for your comments. Only one bathroom in the house, but other outlets are taps in the kitchen and bathroom, wc etc. It's a Keston because it would be difficult to route the flue otherwise.

I guess my question is this: Is there some way of giving the shower priority over other outlets so that the shower does not dry up when basin taps are turned on?

 

[Plumbstar Tom]

you could put flow limiters on the other taps in the house,

 

[BunnyW]

Thanks Tom.

 

[flatcrank]

You need to try to balance the pressures to all taps. Could put ball valves on the supply to the lower floor taps, and throttle them down. Or put in a pressure regulator at the mains, but pipe the combi before the regulator.

 

[Riley]

All in all though it is masking the problem rather than curing it as a Combi boiler is not the way to go if you want more than one outlet running properly

 

[flatcrank]

Agreed, but it is a common issue and depending on the full system attributes can be improved meaningfully at modest cost and effort, so may as well make the best of it.