Plumbing Question

How do i improve water pressure?

Please can someone help me, I am very confused indeed. :-/

I had a small combi boiler fitted a few years ago, but since then my hot water pressure is usless and my cold is really fierce. It wasn't like this before.

It was too hard to regulate a mixer tap shower so I bought a triton cromo single lever mixer shower which we had plumbed to the mains pipes, not the boiler.

But again we are having issues with the fact that too much cold and not enough hot. When turned down to the right temprature it dribbles out of the shower with not enough power to shower a gnat.

And now I have been told that as I have a combi boiler I can't have a pump as it has its own. Is this true? even if the shower is not fitted to the boiler itself?

If this is true how on earth can I sort out this water pressure issue.

Please, please someone help me.
Thankyou all so much for your answers.

I know I will need to get someone in to sort this out. The flow is much less to all hot water taps in the house than it is to the cold.

Also, even though I have a combi boiler I still seem to have a water tank that the hot water is in. I'm not sure why! I always thought that a combi meant that you didn't need a water tank, It heated it as it came through that was the benefit of them. But the plumbers have plumed the combi into the water tank and we still have a timer for water.

The shower was plumed directly into the mains and not the boiler, does any of this make any difference as to whether I can have a pump or not? The shower is perfetic. The valves that turn the water on and off have the hot set to fully open and the cold one actually set lower but still the same problem.

I am so very confused about all of this and wouldn't know what to ask for when calling in a plumber.

Thankyou all.


4 Answers

Best Answer

Hi Libby,
If the pressure is poor at all the hot water outlets then it sounds like the flow restricter at the boiler cold water inlet is partly choked. Its a filter that stops any debris getting into the heat exchanger. Unfortunately you will need to get someone out to either replace the restrictor or clean it.
Libby, it now sounds like the combi is only supplying certain parts of the hot water system & the rest of the house is getting hot water via the cylinder. Switch your combi to hot water only, get someone to open 1 hot tap at a time & watch for the boiler to fire up. This will tell you which hot taps are off the combi and which taps are off the cylinder.

Answered 8th May 2012

Aquaflow Plumbing & Heating Ltd

Member since 24 Apr 2012

Hi libby, if you post the job some one come round and do some tests, but could be plate heat exchanger needs changing or a pressure reducing valve on the cold mains to balance things up, possibly too much pressure for your combi! and limescale could be a prob in your shower!!
if your in southwest area, find us on my builder and invite for job.
kelly plumbing heating & gas

regards kieran
nice user name! ;-)

Answered 4th May 2012

kelly plumbing Heating & gas

Member since 4 Jan 2012

Hi Libby lips,
First of all, no you can't install a shower pump on a combi boiler. The combi works on the mains cold water pressure that comes into the house.
The boiler will only heat the water that it can cope with and it is usually stated on the boilers specs (manual) at how many litres a minuite it will do at a given pressure.
If your cold water is fierce as you say then maybe get a high flow combi that will give you a better flow of hot water.
If the boiler used to give you better flow when it was installed then it may need looking at.
If you have fierce cold water i would have kept your regular boiler and had an unvented hot water cylinder installed as this would give you balaced pressure and a good shower.

Hi Libby,
I think you should post the job on the website and get someone to have a look at this problem you have. If you have a storage cylinder of hot water the you won't have a combi...or you could have it plumbed a weired sort of way. Where are you based in the country?.

Answered 5th May 2012

S.Banks Plumbing, Heating & Eco Energies Ltd

Member since 14 Jul 2009

You dont mention that the hot water to the taps is a problem, so if thats the case the shower is at fault ,is the hot to the shower blocked or restricted in some way , are there limiters fitted in the shower, these are the problems that an engineer would check if the flow on the taps is satisfactory,so post the job and see what happens.

Answered 6th May 2012

sovereign plumbing and heating

Member since 23 Nov 2011

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