how to test mains water pressure- non boaty

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nyx2k

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my wife wants a shower/tap mixer in the bathroom to replace the 2 standard bath taps we have now.

the showertaps i have seen need a pressure of 0.2bar min to work effectively. is there a way of testing my pressure for hot and cold lines before spending £150 on a shower/tap mixer?

system is hot stored water in cylinder in main bedroom and a very big cold water tank in attic.
the cold water out of bathroom taps is very fast but hot is less so.
 
0.2 bar is a trickle.
We had the opposite problem of too much pressure which blew the seals in an instant hotwater shower.
I fitted a pressure reduction valve with a gauge and even though the gauge went up to 10 bar the mains prsessure was more than that. I think I wound the valve down to a bit less than 4 bar.
You could fit a remote powershower pump to provide the pressure needed.
 
i did think of a powershower pump either in the airing cupboard or under the bath models are available as well.

i was hoping to keep the costs as low as possible as my wife wanted it to rinse off her hair in the bath when the separate shower is in use.

some models of showertaps specify upto 1bar so they would need a pump i think.
 
0.2 of a bar is 3psi so your tank system will easily supply that be aware that any bath mixer for that amount WONT be thermstatically protected so you would be advised to have a ballanced supply ie both feeds the same pressure at the moment it sounds likethe cold supply is strait of the mains and the hot from the tank ideally you need to run another cold supply from the cold tank in the loft to the cold side of the bath mixer

Cheers
 
nyx2k said:
are the pumps just a matter of cutting in to the hot and cold water feeds to the shower water pipes
Click to expand...

Yep and a power supply. Would recommend a valve on each line so the filter can be cleaned without draining the system down. Only had to clean my filters once in 10 years.
 
plumbing idiot so please excuse questions.

i can only see 1 hotwater pipe into bathroom from hw tank so wouldnt this boost the pressure to the basin tap hw side aswell if fitted in hw tank cupboard.

also 1 cold pipe from the tank in loft to bathroom where it splits in roof space to supply toilet next to bathroom and then splits agian to supply cold water to basin and cold tap for bath.
 
nyx2k said:
plumbing idiot so please excuse questions.

i can only see 1 hotwater pipe into bathroom from hw tank so wouldnt this boost the pressure to the basin tap hw side aswell if fitted in hw tank cupboard.
Click to expand...

Yes, so not a good idea, 'cos (1) makes pump run every time the basin tap is used. (2) Giant stream from said tap whenever used....
Better to fit booster under bath if poss: (as I did)

also 1 cold pipe from the tank in loft to bathroom where it splits in roof space to supply toilet next to bathroom and then splits again to supply cold water to basin and cold tap for bath.
Click to expand...

Shoer boost pump need supply from cold as well as hot water feeds, and this is more conveniently sourced from under the bath, as the pipe runs will be nearby each other.
Then of course you have the rule of 'leccy in bathrooms, not allowed for unqualified persons / nasty results (aka 007) if you get it wrong etc, etc,

Hopefully more details from practising plumbers /electricians along shortly
 
Going back to the original question, if the surface of the water in the cold storage tank is 2 metres abowe the shower head then there should be at least 0.2 bar pressure for the shower.

It has been suggested that the cold water to the bathroom may be at mains pressure although I think that would be unusual. Try hold your thumb under the cold tap to block the outlet. Then turn the tap on. If you can resist the pressure then the tap is connect to the tank the same as the hot supply. If it is at mains pressure then you will not be able to hold it (and will probably get wet).
 
after tracing all the plumbing the cold water to the bath taps and basin taps are from the attic tank and the hot to bath and basin is from hw cylinder in bedroom.

the height of the shower head from ther bottom of the cold tank would be 1.4mtrs so only 0.15bar so not enough..

however i discovered this morning that i can buy a power shower with internal pump that just needs a hot and cold feed at 0.1bar prerssure so it may be more expensive but would be easier to do than putting a pump under the bath or next to hw cylinder.
 
thanks for that.
it seems the reccomend a power shower, so i can take the hot and cold feed directly from under the bath where the hot and cold feed to the bath taps are
 
KISS?

nyx2k said:
the height of the shower head from ther bottom of the cold tank would be 1.4mtrs so only 0.15bar so not enough.
Click to expand...

It's the surface of the water in the tank that's important so you've probably got enough pressure. But if it's only for occasional hair rinsing why not get a "push-on" shower head for the bath? Cheap. Simple. Easy to fit - no need for plumbers or electricians.

See, for example, here.
 
we tried the push on ones before and the taps are an odd shape so the rubber doesnt fit and sprays water around the bathroom even when the taps are turned to a small trickle.

it looks like i may need to wait till payday and get a powershower with in built pump.
 
Modern plumbing practice is to supply all cold outlets from the rising main therefore generating mains pressure at all cold outlets and allowing drinking water to be available throughout the house. However it is common to supply the cold feed to the bath from the header tank so that equal hot and cold pressures exist at the bath outlets and a mixer tap/shower can be used. You may find that the flow rate of the hot water is less than the cold due to the increased resistance through the hot water cylinder and associated pipework. (The static pressure will be the same at no flow condition). In your case one solution would be to raise the header tank which would increase the pressure available with minimum plumbing work if you have sufficient headroom (simple put a grid of 3 x 2's under the tank). You need to maintain access to the interior of the tank so that you can inspect/service the ball float valve.
 
that would explain the massive pressure difference between the bath and downstaiars sink pressure as the sink in kitchen is fed off the mains water
 
nyx2k said:
thanks for that.
it seems the reccomend a power shower, so i can take the hot and cold feed directly from under the bath where the hot and cold feed to the bath taps are
Click to expand...

0.1018


'A mixer shower uses a simple shower valve to blend your hot and cold water supplies to achieve the showering temperature and flow that you desire.

Mixer showers are ideal when fitted onto a gravity site situation, i.e. a separate hot and cold water supply, gravity fed by a storage tank of at least 112 litres (25 gallons) capacity. They require a minimum head of 0.1bar (1 metre) between the bottom of the cold tank and the handset position.

The 100 Series Thermostatic mixer shower can be fitted directly onto high/unequal installations without additional fittings being required.

For a typical gravity site situation mixer showers may also be combined with a remote shower pump to give a ‘pumped shower’ with ‘power shower’ performance.'

You don't have to use a pump unless you would like a 'power shower', as they have handsets for both high and low pressure.

0.512


Ours is not unlike this. I installed it on a stud wall, retrofitting the pipes from above. The plate covered the hole in the wall where the pipes connected with push in fittings so not involving plastering. Presumably you plan to tile anyway so even if you need to chase it out that could cover up the mess.

If you take separate supplies from hot and cold tank for the shower you may not so readily be suddenly surprised by a change in temperature because someone has opened a tap elsewhere.:eek:
 
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