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Plumbing

Mixer tap bathroom (shower) – water pressure drop when turning cold on

Anonymous user 03/03/2024 - 3.22 PM

Just want to get some peoples thoughts here. I have a decent pressure hot feed coming off the boiler to the bathroom but as soon as I turn the cold on the pressure to the hot just drops. The cold feed to the bathroom comes off the loft tank (cold only), and is not the highest pressure, but what I don’t understand is why the pressure to the hot feed drops if I try to turn the cold on at the same time – they are both being fed from different places. Is it possibly just the mixer tap itself? Or I have been reading stuff on non-return valves and am wondering would installing one help (presuming there is not already one there)? I am considering capping off the loft tank and connecting the cold main feed running already running into the loft to the existing cold feeds in the bathroom. Any ideas or recommendations? Thanks

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4 Answers

FJL Plumbing & Heating

No reviews yet

Manchester
Hi, When you turn the cold water on at the same time you are turning off the hot water flow, having fed the cold water from the loft tank the pressure is much lower and therefore your final pressure is not as high as it's the hot water only. You would fix it feeding the cold water from the mains. Hope it helps.
Answered6 June 2019
10

MG Heating and Plumbing

Rating: 3.7 out of 5
South Croydon
Sounds like the mixer tap itself. Changing the cold to the mains will give you unequal pressure which could affect any shower mixers you have.
Answered17 June 2019
1

Anonymous user

What is the head of water height from tank to shower outlet and is the hot fee Fed from the cylinder
Answered7 June 2019
0

PDunn

Rating: 5 out of 5
Holloway, London
Is this only in the bathroom.? Are any other outlets with the same thing when running the hot tap? You don't want a non return valve on a gravity fed system.. If your hot water is fed instantaneously (combination boiler) then you have an unbalanced hot & cold system.
Answered15 June 2019
0