DIY Doctor

Loss of water pressure.

Postby ballysingh31 » Wed Apr 30, 2008 2:43 pm

I am having problems with my shower. I have a mixer shower.

I removed the hose from the mixer and the water pressure is still really poor. when I turn the thermostat to cold, the water pressure picks up.

their is no issue in the water being cold, because it does get hot. Yesterday when we lift the head up high water dribbles a couple of drops, if lowered to the bath then we get some flow.

Do you think I should remove the mixer to check if this is causing the issue.

The pressure for hot water in the taps is reasonable. My hot water tank is on the same level as my bathroom.

can you help?
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Simply Build It

Postby rosebery » Thu May 01, 2008 12:42 pm

It's the height difference between the water level in the COLD water storage tank in your roof to the shower head which affects your pressure and therefore your flow rate.

When you have the shower head down in the bath it's probably about 2 metres giving you around 0.2 - 0.25bar.

When you raise the shower head up to the level of the bracket you reduce the static water head and therefore the pressure drops.

That's why it's dribbling.

The cold / hot differential is probably because you don't have the hot / cold feeds properly balanced.

Incidentally, the I'm not clear if it's a thermostatic mixer or a bath shower mixer. Could you clarify? If its a BSM it will WILL reduce the water flow because of the divertor but that's not your primary problem.

Has the mixer got separate feeds from the CWS in the roof and the HW cylinder. That is to say separate from every other tap? If not it should have. That is easly accomplished for the cold feed but will require a Surrey, Deleted or Warix flange to be fitted to the HW cylinder. Both these feeds should then go to a double ended pump to raise the pressure to an acceptable showering level when the shower head is in the wall bracket.

Does that help?

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Postby stevenc1603 » Thu May 01, 2008 3:11 pm

Has it always been like this or has it just started getting worse and worse?

I'd have a look and see if there are any filters in the inlets on the showers. If you are in a hard water area they may be clogged with limescale.
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Postby htg engineer » Thu May 01, 2008 3:23 pm

Remove the shower and clean or replace the filters, it'll probably be a build up of limescale affecting the flow.
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