Unbalanced water pressure on mixer shower - Help please

jjfresh66 · Posted: Mon Feb 04, 2008 3:16 pm

hi,

At the weekend I fitted a new bath mixer shower for my mum - It wasn't a cheap one either. It took me about a hour just to get the tap nuts loose as i had about a 3 inch gap with pipes in the way etc.

Anyway it's an open system, gravity fed so I new it wouldn't be the most powerfullest shower but that's not the problem. The pressure is fine on both hot and cold, it's just trying to get the combination of a rasonable temperature to get washed in - as apposed to freezing or redhot. I messed around for about 15 minutes with no joy - it jumps from redhot to cold with the slightest turn.

The cold taps in the bathroom are fed from the rising main. I've been told that this is my problem, because the two are unbalanced.

So am i stuffed guys with an unhappy mummy or is there some gadget that can sort it.

Thanking you all

JohnD · Posted: Mon Feb 04, 2008 3:22 pm

jjfresh66 wrote:

...it jumps from redhot to cold with the slightest turn...

another cause is if it is thermostatic and you have put the hot pipe on the cold inlet and vice versa

to run a mixer shower you need balanced pressure supplies.
Best way is to run a new cold pipe from the loft tank

you could try a pressure reducing valve, would cost you in the region of £40

jjfresh66 · Posted: Mon Feb 04, 2008 3:59 pm

Cheers john,

Would a pressure reducing valve work. I don't mind spending that as long as it will do the job. Also if i turned down the stop cock to the cold, would this have the same effect as a control valve.

Thanks

seco services · Posted: Mon Feb 04, 2008 4:25 pm

turn down the stopcock reduces the flow not the pressure.

Agile · Posted: Mon Feb 04, 2008 4:28 pm

You would have been better occupied repiping to supply the cold from the LP stored water.

Then it would have been balanced and you would have had the option of fitting a shower pump.

Tony

Terrywookfit · Posted: Mon Feb 04, 2008 4:31 pm

I did warn you on Saturday but your reaction was!!!
Quote,
Oh well it's my mums, so she will be the one who suffers when the shower goes really hot or cold. will be like one in really cheap and nasty bed and breakfast joint at the coast. Arrr Fu**ing shower is rubbish. LOL

Thanks again - have a nice weekend

jjfresh66 · Posted: Mon Feb 04, 2008 5:49 pm

I know and admit I messed up Terry - more to the point would a reducing valve make it work ?

Thanks

jjfresh66 · Posted: Mon Feb 04, 2008 5:59 pm

seco services wrote:

turn down the stopcock reduces the flow not the pressure.

Right - gotya like Volts and amps

Terrywookfit · Posted: Mon Feb 04, 2008 6:06 pm

I have no experience of using a PRV in this situation!

My advice would be to install a tank fed cold supply!

JohnD · Posted: Mon Feb 04, 2008 7:38 pm

I had a shower with PRV on mains cold (I have a 10m+ high house so about 1bar of hot from tank)

it worked, but tended to stick (infrequently used guest room shower)

jjfresh66 · Posted: Mon Feb 04, 2008 8:09 pm

Thanks for all the comments.

I'm going to order a Pressure equalizing valve from Plumbworld. £39.99

Equalises hot and cold water pressure by automatically adjusting the higher water pressure to balance with the lower

Will get back with a positive result hopefully later on in the week.

Cheers

jjfresh66 · Posted: Thu Feb 07, 2008 6:33 pm

Update

Installed a Honeywell pressure reducing valve onto the cold feed - I've messed with this to try to get the same pressure as the cold. - It still didn't do the trick mind.

It's certainly slowed the cold water pressure down but it's still no good to shower in. I'ts improved a little, now from cold, if the hot control flow is increased slightly, it will take around 20 seconds till red hot - vice versa.

Basically cant get the balance right !!!

Do the hot and cold have to be bang on equal pressures for this to work - I messed with the control valve for ages trying to get this right.

Think I will give it up as a bad job - unless someone has a good idea that's not too complicated.

cheers

Cindle · Posted: Wed Jun 04, 2008 6:16 pm

Hi. I'm having much the same problem as you. Did you ever manage to sort it out? If so, could you please tell me how!!
Many thanks
Phil

JPC · Posted: Thu Jun 05, 2008 12:20 pm

phil...better to have startedyour own thread....however. what you need is a pressure equalising valve...not a pressure reducing valve...jj was so close..he even mentioned it, but seems he go the pressure reducing

get an pressure equalising valve and it will be ok...it will only run at slightly more that the hot pressure you get..poss double i guess...so it wont be a "power shower "

You can get them for about £38 ??

jjfresh66 · Posted: Sun Jun 08, 2008 7:58 am

Cindle -

This proved to be a nightmare situation - do not go for pressure reducing on a mixer (does not work) Pressure equalizing valve will but your shower will just be a trickle with no real power to enjoy the benefit of getting a shower.

I bought an electric high wattage shower and this seems to have been the best solution for this config.

Cheers