Low mains water pressure

[cb31]

I've got a problem with my bathroom shower in that the flow rate is not high enough. The shower is a head connected via a hose from the bath mixer taps.

With the shower head below the bath taps it is fine but when you raise it 1.8m onto the rail the flow drops considerably. If you use just hot it is fine, just cold and the flow rate is terrible. What this means is that the shower becomes too hot to stand underneath as it is virtually all hot water.

The heating is provided by a Worcester 24cdi combi boiler and has 22m pipes at the bath taps end, cannot see the start as they are buried in walls. My house is a top(4th) floor ex-council flat.

As the flow looks ok I presume it is a pressure problem. I don't know how the cold feed gets into the building, I don't think it is a tank on the roof. Can anyone suggest a way to remedy things such as a pump or something? Thanks

 

[kvsalamander]

Im not allowed to be seen to be advertising but a well known manufacturer of pumps has a boost for the home that may be suitable.

regards

ken

 

[doitall]

If the pressure is ok for the hot from the combi, the best road would be to change the cold to mains so they match.

 

[cb31]

If the pressure is ok for the hot from the combi, the best road would be to change the cold to mains so they match.

Sorry but you've lost me. I thought the cold feed to the kitchen and bathroom was already a mains feed? Are you saying that the cold feed comes from the combi-boiler usually? Is there an easy way to determine if mine is from the mains or via the combi? Does a combi slow down/reduce a cold feeds pressure?

Living in a block of flats it is difficult as the pipes are buried in the walls so it is difficult to see how things are connected. I still haven't found the water cutoff for the flat, either it doesn't exist or it is buried somewhere inaccessible.

 

[Charnwood]

A lot of council blocks have communal tanks on the roof etc. Maybe your cold comes from that, giving a low head of water.

 

[gregd72002]

to me, it looks like the cold inlet to the mixer simply needs to be cleaned

How the heck hot water has higher pressure than cold water if not some rubbish in the cold water inlet...


or, there are some PRVs and they are not in sync...

 

[Charnwood]

How the heck hot water has higher pressure than cold water if not some rubbish in the cold water inlet...

Possibly because hot is mains and cold is tank. Possibly.

What does the cold from the basin run like? Can you stop it by putting your finger on the end of the spout?

 

[doitall]

Possibly because hot is mains and cold is tank. Possibly.

What does the cold from the basin run like? Can you stop it by putting your finger on the end of the spout?

That was my thinking as well.

 

[cb31]

It seems to run plenty fast enough out of both the kichen, basin and bath taps. The flow rate is fine I think, 12l/min cold, 8l/min hot out of the bath taps, which to me sounds like there is plenty of water but not enough pressure to lift it up a couple of metres. I've not tried to stop it with my finger but will do when I get home.

The weird thing is the shower head works fine when it is around the same height as the bath taps where it is attached, but when you lift it up 1.5m the cold slows markedly. It was even worse before I got an extra large bore shower hose. To make it bearable I've put the boiler hot water temperature to as low as it will go but not good for baths.

 

[cb31]

I tried to stop the basin and bath taps with my finger to no avail, it was gushing everywhere.

I presume this means there is plenty of pressure at tap height but not 1.5m above? I will try to get on the roof next weekend when I can get a ladder to see if there are any storage tanks.

Any other suggestions?

 

[gregd72002]

1.5m is roughly 0.1bar and this is very very little. So the answer is - this is nothing to do with the height... there is something else wrong (i.e PRV or blocked inlet)

Unless, basin Tap and shower are fed from different sources

Maybe the mixer is broken?

 

[cb31]

I agree and that makes perfect sense, however if I hold the shower head at the tap height it is fine. As I move it upwards the flow weakens. Could this just be a faulty mixer tap, the tap is only a month or two old? The basin and bath taps are coming from the same hot and cold pipes.

I massively regret not spending the extra and getting a proper thermostatic shower now. I would spend the money tomorrow but am worried I will waste money if it doesn't fix the problem, not to mention all the messing with the new tiles etc.

 

[Agile]

You have now told us the tap is new!

Its probably designed for high pressure supplies!

What you have told us is conflicting!

All I can suggest is that you get an experienced plumber to investigate for you.

Tony

 

[cb31]

Sorry for the confusion. I replaced an old electric shower with new bath taps with a shower mixer outlet. This is the tap

http://www.bathroomheaven.com/emeli...th-shower-mixer-tap-exc-shower-kit-10346.aspx

It says it is suitable for low and high pressure systems, is this not really true?

I don't mind getting a plumber in but don't want to waste time and money if it is something simple or stupid which I can fix. I'm only in the flat 2 nights a week so would have to take time off work to get someone round.

 

[Agile]

The tap looks OK but there is clearly something wrong!

Moving a shower up 1m changes the pressure by 0.1 Bar. You can easily hold a finger over a tap with up to 0.5 Bar pressure. You say you cannot!

It just does not make sense what you have described!

Who fitted the new tap?

Tony