Low pressure in Kitchen Hot Water Tap; Solution=Shower pump?

8 Apr 2007
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United Kingdom

I've just replaced the tap in my Kitchen as the old one was past its use by date.

Anyway, I have low pressure from the hot water tap (it was like this with the old tap, too) and want to boost the pressure. I was told that I can boost the pressure using a shower pump; is this true? If so can someone recommend me a shower pump?

Extra Details
I live on the ground floor. The hot water is fed from a hot water cylinder on the ground. Another water tank is about 1m above the cylinder, which is where I presume the hot water is getting its force to come out of the tap in the kitchen.
The cold water is fed from the mains, hence the cold water pressure in the kitchen is excellent.

Im thinking of installing the pump underneath the kitchen sink.

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No, I was just hoping that someone...anyone, would give me some advice on this. I wasnt specifically calling a person who goes by the name of 'anyone'.

Judging by the lack of responses here, perhaps shower pumps arent used that frequently to deal with lack of pressure through taps. I shall probably get the pump and see if placing the pump underneath the sink, away from the hot water cylinder, works or not.
I thought Kev was replying to 'anyone'.

Anyway, I have just emailed Salamander tech support. After they have replied I shall post their reply here for all to see, for future reference, just in case someone else also wants to do this sort of thing, ie. boosting a hot tap, rather than a shower.
kevplumb would never do that - he's the consumate gentleman, with ne'er an unkind word nor an ill wish towards anybody.
Here is the reply I got:

All our pumps require an independant feed from the hot water cylinder. The pump has to be the 1st tee off the hot water cylinder and if you are intending mixing with the cold mains you will need to add and RCM3 to your pump so that it will work with cold mains.

Ideally if you wish not to meet with the installation criteria then please do not expect to receive a warranty with the pump. What you are most probably looking for in your application is what we call an in line pump. We are the wrong company for this. You ideally need to speak with Pump World their number is 01793 820142.

So, it seems that I need an inline pump, which is what I was originally thinking about. Im now thinking along the lines of an Eheim 1048 pump, connected underneath the sink.

I have emailed plumb world to see what they suggest.

I went ahead and installed a EHEIM1250 pump underneath my kitchen sink for the hot water tap. This did increase the water pressure, however, it just wasnt strong enough.

I then emailed Stuart Turner regarding my problem:

Dear Sir/Madam,

Currently my (new) kitchen hot tap has a very low flow rate (approx 1.5litres/minute). In order to solve this I would like to install a pump, to boost the hot water flow and pressure to the said tap. The tap in question is a mixer tap and will mix hot water with mains cold water.

The pump I intend to purchase for this use is: Stuart Turner Single 3.0Bar Positive Pump.

My question:
1. Can my choice of pump be used for the above purpose?
2. Is there a more suitable pump for the above purpose?
3. Is there a better method by which I could achieve a pressure boost in my kitchen hot water tap?

Their reply:

Dear Sir

re your recent e mail

If the mixer tap you are pumping to mixes within the body of the mixer you will require a negative head pump, either the 2 bar negative single or the 3 bar negative single depending on the required performance, either pump would require a dedicated 22mm supply, the installation manual for this pump can be downloaded from our web site www.stuart-turner.co.uk for your information.


So, I went out and bought myself a Stuart Turner Negative, Monsoon Extra, Single, 2.3Bar pump. I got this on ebay for a bargain price of £127. The cheapest place selling this pump was around £300inc.

Today it arrived and I fitted the pump.

First impressions: its huge.
FItting the pump: although it is recommended for the pump to be fitted using 22mm pipe fittings throughout, I used reducers and connected it using 15mm piping.
After fitting the pump: I realised just how noisy it is and once again just how large it is. Even at just 2.3Bar, its pressure is phenomenal. When used with my pull-out spray tap, the pressure is so much that I cant turn the tap to full power, as the spray wets the entire area around the sink. The pressure pushed by this pump is greater than the pressure I get from the mains water supply, which the mixer tap is connected to.

So there you have it. If you need a boost for one tap only, then you can still receive this boost without having to place the pump just after the water leaves the hot water tank. Of course, if you dont connect the pump in the way that Stuart Turner advise, you wont have any warranty, so its upto you if you are happy to take this risk.

As an aside, due to the immense pressure being put out by this pump I am tempted to re-place the pump so that it is connected right after the hot water cylinder so that it boosts the pressure to all hot water taps around the house.

I hope this thread helps someone else in a similar situation, in future.
i would be careful if the pump is as powerful as you say prolonged use may run the feed tank dry and knacker the pump!
For the feed tank to run dry I would need to run the tap at full whack for quite some time (hot water cylinder and cold water tank which feeds it are large and when I drained the hot water system last, it took at least 20mins, with the mains water turned off to prevent the tanks from refilling) and as I am the only occupant in my home I never run the kitchen sink tap for more than a few mins at a time.

Thanks for the heads up though. I shall monitor this and be careful when running the hot water tap for long periods of time.
I dont have a bath. I have an electric shower that is supplied directly by mains cold water.

The main reason I think for the poor water pressure/flow in the kitchen is that the tap is a pull out spray tap which uses very narrow bore flexible tubes. This means that it is very difficult for water to pass through the tap, unless it is pushed through at high pressure.

The bathroom tap does not suffer from this as the tap is directly connected to the 15mm pipe, giving prenty of water flow through the tap.

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