Combi Boiler, Shower pump problem!

paulms · 28 Mar 2010

Hi all,
I was wondering if anyone could give me some advice please. I have a Saunier Duval combi boiler in my 3 bed house, i have a shower which seems to have a sort of low pressure this is the same level of flow as the rest of the house when you turn the hot water on.

My question is i want to fit a pump to assist the shower with pressure the combi sits just behind the shower about 2 meters away in the airing cupboard. Can i just buy a hot and cold pump for the shower or do i need a special pump due to the lack of a water tank in the house?

If anyone knows a good item to go for could the please state what model it is and where it can be purchased from.
Thanks for the replys.

tripty · 28 Mar 2010

Hi,

Unfortunately, you cannot fit a shower pump directly to a combi boiler. You would need to add a hot water cylinder and cold water cistern, heating the cylinder indirectly from the combi.

However, before you go down that expensive route prehaps you should investigate the shower first; what is the pressure like on the other outlets fed by the combi? What is the make and model of the shower? Is it suitable for a combi boiler?

Also, what is the incoming mains pressure and flow rate?

Hope that helps

paulms · 28 Mar 2010

Thanks for the reply
I basically could not fit a hot water cylinder and cold water cistern in the house due to the room it takes up. The boiler reads a pressure of around 1 bar to about 1.7bar after the heating has been on but this is a sealed system all rads have thermostatic valves to adjust pressure aswell.

The cold water flows very fast from taps, the make and model of the mixer shower is unknown as it was put into the house when built its only 2 years old.

Is there a way of checking the mains pressure and flow rate ? I have heard that showers get blocked up could this be a possibilty as the mixer has something white in colour and hard to remove from the pipe looks like limescale round the entrance pipe to the shower possibly.

So i guess i am possibly going to have to live with the pressure or flow rate of the shower, the head and flexi pipe from it are new. so these items are not affecting the fast flow rate im missing.

tripty · 28 Mar 2010

Hi, to check your mains flow rate get a bucket and time how many litres the cold kitchen tap outputs in 30s, then times by 2 and you have your mains flow rate in litres/min. To check the pressure you need a gauge, google for "mains pressure gauge".

If the house is a new build <2 years old then can't you get the developers round to sort it out?

The shower could get blocked with debris so its a good idea to clean it out, what sort of mixer is it? If its easy to take off the wall then do and clean any debris from the inlets and flush the pipes. Did you always have this problem?

Worst case is that your mains flow isn't up to the job. Or that the boiler is really crap and can't heat the hot water up enough, quickly enough and is thus restricting the flow rate through it.

Whats the hot flow rate like on other taps?

PEDANTICVINDICTIVEMAN · 28 Mar 2010

Inlet filters ?

numpty1 · 28 Mar 2010

scaled up shower head

paulms · 28 Mar 2010

I got about 11 litres out the cold tap so thats 22 flow rate
The other hot taps in the house all perform the same as each other.
Im going to remove the shower mixer from the wall and clean it to see if it helps with the problem im having.
The developers of the house would not come round to sort this out. The previous owner of the house was the daughter for the man who owned the company who built the houses here. I guess she never cleaned it out as it was new.

The boiler has ran faulty once but was covered and repaired the repair man said it was a decent combi and could handle the house supply quite easily as if it was almost to big for the demand it would be given by us.

paulms · 28 Mar 2010

The shower head and suppply pipe are new so the problem has to be behind them ie from the shower it self.

tripty · 28 Mar 2010

okay, sounds like the flow rate is up to it.

cleaning the shower valve will hopefully sort it out

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Combi Boiler, Shower pump problem!

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