Low cold water from shower

[jakakaka]

Hi,

I've just had a flat renovated and there is a problem with the flow or water pressure for the shower. When turned to hot, the water pressure is poor but when I turn the tap to cold hardly anything comes out of the shower at all. Just a dribble of water.

I believe that the cold water comes from a cold water tank in the loft. The hot water from a combi boiler.

The shower is the Victoria Plumb shower combination 7, a triple-valved thermostatic shower.

The contractor says that the problem is the water pressure which sometimes drops to 0.8 from the mains.

I'm really totally clueless about these things so my apologies in advance for inaccurate or incomplete information. Thank you to anyone with advice.

 

[JohnD]

I believe that the cold water comes from a cold water tank in the loft. The hot water from a combi boiler.

I certainly hope not. That would be crazy. Nobody competent would install it like that.

 

[jakakaka]

Thanks for commenting. I better check on that but if that is how the system is set-up, what would the problem be?

 

[Hugh Jaleak]

If a combi is fitted the tanks should have been removed, or at very least emptied and abandoned. To install properly on a combi cold should be mains fed, hot from boiler hot water outlet.

Bear in mind though, the flow from the shower is completely dependant on the mains feed into the property, poor mains feed will result in a dribble from the shower.....

 

[jakakaka]

If the problem is the mains feed, is there anyway to solve it? Or at least, improve performance?

 

[Hugh Jaleak]

May involve laying a new service pipe from the road into the house, but unless the performance from the main in the road is up to it, a new service isnt guaranteed to solve anything.

An accumulator may be a possiblility to boost poor pressure/flow.

 

[duffin]

how big is the cold tank? possible to pump just the tank...

 

[jakakaka]

Not sure the size of the water tank.

I spoke to the contractor about the cold water coming from the tank. He said that because the water pressure is so low, if you ran the cold water from the mains, the pressure would drop when you had a shower and activate the boiler's automatic cut-off. does this make sense?

 

[JohnD]

fill a bucket at the kitchen sink, once from the cold tap, once from the hot, time it.

How many litres per minute do you get from each?

 

[jakakaka]

Thanks for the comments John, Duffin and Hugh.

Testing the water-pressure: The kitchen sink has been disconnected so that the worktop can be installed in January. Is there another way to check? I am back at the flat on Thursday and will do my best to check out the system.

Cold water tank:

A. If the mains pressure is very low, would connecting the cold water system to the mains cause further reduction of the water pressure?

B. Could this reduction of the water pressure cause the pressure in the boiler to drop (below 0.4) and the automatic shut-off to activate?

Many thanks.

 

[duffin]

turn off stopcock. go to bathroom and see what still works- this is off the tank. turn on stopcock. if bath/shower is off the tank, pump it. and the 0.4 pressure is normally for the central heating monitoring only- top up and it will work.