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Plumbing

Low water pressure when two usages of water in the house

Anonymous user 28/02/2024 - 3.05 PM

I live in a shared house of five, and as long as I've lived here we've had a pressure problem. Whatever you are doing with water, if someone else is using a tap or the washing machine the pressure drops. So if you're having a shower and someone turns on a tap the pressure goes. There doesn't need to be more than two usages of water in the house for this to happen, so it's not as if five people are using it at once. We have a combi boiler, and I've been reading a bit about that and 1 - 1.5 pressure. Ours is a bit above 1, and even the cold tap affects things so I don't think this is an issue. My question is, is it likely the mains water supply into the house is the issue? I'd like to approach my landlord about finally getting it sorted (interrupted showers are a nightmare), but want some idea of what it might entail in terms of work.

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2 Answers

Anonymous user

The indicated pressure on the boiler gauge is for the heating side and unconnected to the hot and cold supplies. A combi boiler tends to have 15mm outlets for the hot water so flow/pressure will suffer if more than one outlet is in use. It is likely that the cold supplies in the house are undersized, unfortunately this is a common problem and often expensive and disruptive to remedy.

Answered16 August 2014

Martin House Plumbing Services

Rating: 4.8 out of 5

Lymington

Hi. If you had a pressure balancing shower valve such as a Mira 415 then this would take care of the problem. The overall flow rate would still drop but the temperature should remain constant. That is if there is still enough flow to keep the boiler firing. This type of valve was designed specifically for use with combis, although can be used successfully in some other situations also. You really need to have the standing pressure checked as well as the flow rate in order have a better understanding of what is going on, as a small improvement gained with a better shower valve my not really justify the expense. You could also try increasing the flow rate through the boiler if the water at the moment gets very hot. That may well deal with the problem but I suggest you have a professional look at it. I hope this helps

Answered8 April 2017