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Increase pressure for newly fitted shower


I have just fitted a new shower in the upstairs bathroom however, there seems to be an issue with the water pressure. I put iso elbows at the hot and cold taps and ran pipes up to the shower above the bath. We have a combi boiler and hot water seems to flow reasonably well. The cold doesn't seem to run so well and all the cold outlets in the bathroom come from a water tank in the attic (none of them appear to be mains fed). Could this be cause the shower to have a weaker flow?

3 Answers from MyBuilder Plumbers

Hot and cold preasures are unbalanced. conect the cold supply to the shower to a mains fed supply this should improve your situation so long as the shower valve is operating properly.


Answered 17th Sep 2012

Hi - where there is a combi boiler, cold water feed is usually connected directly to the mains.

However, the unless proper tests have been carried prior to fitting the combi boiler, water pressure drops immediatley when two or more taps are turned on.

Please check and ensure that the tank really does feed the taps, as some plumbers do not remove the tank from the loft, merely disconnect and fix the rising main in the attic to the cold feed - trace the pipe work to be absolutly sure.

If the tank is used to feed the cold water to the bathroom it could be, that the tank in attic is used to to compensate for lack of incoming mains pressure, do you know the level of the water pressure coming into the home? There also needs to at least a distance of 1 meter between the water tank and shower?

You may also want to check if the shower you have fitted is suitable for low mains pressure, please appreciate by fitting a single impellor pump on the cold, this may overwhelm the hot feed and you will only get cold water from the shower or other taps in the bathroom, depending on how the tank is connected.



Answered 17th Sep 2012

spot on, when fitting a combi boiler all cold feeds should be fed through boiler for exactly this reason. if pipework is too difficult to reroute you could fit a pump to your tank fed cold supply, not ideal but may be your cheapest option


Answered 17th Sep 2012

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