As above, just been decorating my downstairs cloakroom. I've replaced the toilet and sink but since replacing the sink I seemed to have lost water pressure from the hot tap.

The old sink had individual hot / cold taps and although the pressure from the hot wasn't as good as the cold it was fine for washing hands etc..... However, I've put a mixer tap in there now and a lot of the pressure has been lost.

Now the only other changes / alterations i've made to the pipework is that i've added an extra isolator on the pipes, due to the location of the sink it was difficult getting to the original one so I've kept it in place (fully open) but put another one further up the pipe. Would this make a difference on the pressure going to the tap? The pipe is standard 15mm copper and have used speedfit connector to route it. Someone has advised to possibly put a gate valve(?) in place rather than an isolator as it doesnt restrict flow when open?

I'm by no means a plumber so feel free to shoot me down!!

Cheers
Chris

 

Would have a guess the iso valve is the smaller bore than the full bore valve that would be why you dont have great pressure,go to your plumbers merchant and ask for a 15 mm full bore iso valve

 

Yes I think it is a smaller bore. I'll get the larger ones and see what happens. Thought it couldve been the tap causing the problem as its one of those waterfall type taps, although the hot just dribbles out!!!!!!!!!!!!

 

Possible airlock in the pipework?

 

Is yoru system gravity fed and if so is the tap compatable with gravity feed?

When i was buying the stuff for my mums new bathroom i couldnt get the tap i wanted because it was only for mains pressure systems

 

Your valve you used, was it a full bore valve?

 

Steve - not sure about the airlock mate, when i first turned it on it coughed and spluttered then flowed/dribbled out after. All the other hot taps in the house are fine. Valve wise not sure, I dont think it was, its just a conventional isolator valve I got from screwfix?

daviddunlop - not sure mate, this is the tap I have: http://cgi.ebay.co.uk/ws/eBayISAPI.d...=STRK:MEWAX:IT

Thanks
Chris

 

hi i have been a plumber for years it is get a gate or leaver valve will sort it out

 

depends if you on tank feed system ,mabe air lock or the cold is mains pressure an hot isnt try turning valve down for the cold .if you on mixer tap you need same pressure hot an cold

turn hot and cold on (if mixer tap )and hold hand over tap end so water car'nt come out , shud shoot the air back to cylinder with pressure off the cold

 

It is a tank fed system, turned the cold down to try and compensate the mixer but nothing, still cant feel the hot. Going to try the full bore isolators first then perhaps try the mixer tap from upstairs that works ok?

 

I bet the mixer tap goes from 15mm to 10/12mm pipe into the bottom of the acctual tap....if so, thats your problem right there....

 

[quote=cfoster;4931377]It is a tank fed system, turned the cold down to try and compensate the mixer but nothing, still cant feel the hot. Going to try the full bore isolators first then perhaps try the mixer tap from upstairs that works ok?[/qu


you will find up stairs is tank cold an down stairs isn't ,lota houses like that,did you turn cold down just going in to mixer tap as turning stop tap for house wouldnt work

 

The cold tap is absolutely fine, superb pressure, had to turn it down at the isolator by the tap to control the flow as it was too much fully opened.

Tiff - your right mate the flexible hose suppled with the tap does have a smaller fitting going into the tap, thought it wouldve been a conventional size though (see ebay link for tap further up!).
Just bought a full bore isolator so will try that and see what happens!

 

i have the same taps and the basin one doesnt exactly flow out at great pressure unlike the bath filler one. try the valve and let us know.

The bath filler:



basin tap:

 

Update: I fitted a 15mm full bore isolator to improve the flow but unfortuntely still no good. Its got me thinking that perhaps I need to replace the mixer tap with a conventional type one with a spout that points downwards, rather than a wide spout that shoots out sideways (see Sean's pics above). This way the hot water should drop out of the tap?

Also quick question on basin waste, bought a plughole etc (one of those coin flip type ones). However its leaking!! I've fully sealed it etc. Now it does have the overflow holes around the sides but got a feeling I may need one without the holes? How do I know if my ceramic basin has built in overflow?!! (sorry im new to this plumbing lark and the old man is on holiday at the mo!!)

Chris

 

have you fitted non return valves

 

Whats one of those? There wasnt one on the original pipework?

 

you can get pressure equalising valves you will then have the cold flowing as slow as the hot lol

 

right have you hecked the flexi hoses coming off the tap arent twisted? as the slightest kink/twist can cause them to give you problems,

is your hot water fed from a combi boiler direct or a cylinder indirect? easy way to find out is do you have a big hot cylinder in your house or not?

is the bathroom upstairs or downstairs? as if upstairs and hot water is fed from a tank in the loft through your cylinder your not going to have very good pressure anyway, therefore you would be better off with some kind of pump setup or electric immersion heater for upstairs coming off a cold main,

does the tap have a british standard mark on it something like bs5544 atall? if not im suspecting the tap mixes inside instead of at the end of the tap and the cold pressure is pushing the hot pressure back downthe pipe if the hot is fed from a tank/cylinder indirect setup, and therefore a non return valve on the hot might help that out,

fitting a bigger isolating valve i would suspect will do nothing in solving a pressure problem when it was fine before hand, fitting a new one might if the old one was nackerd and staying half closed

 

Tony, downing the cold pressure would make the tap totally useless, not just 100% useless!!!!!

boyracer-1 - most of the answers are above mate, but in short its a downstairs cloakroom being fed by gravity from a tank upstairs. Pressure isnt fantastic so not expecting miracles. No desire in putting in immersion heaters etc as 'its only' a downstairs hand basin.

I imagine the tap would be approved? The link to where I bought it is here: http://cgi.ebay.co.uk/ws/eBayISAPI.d...=STRK:MEWAX:IT

I think it does mix it inside as i cant feel the hot / cold from either side of the exit. Non-return my help but when the mixer is on full hot its still rubbish? I really think I need to get a more conventional mixer rather than the one I have. Having the water coming out of a spout rather than a wide waterfall type exit would make it better wouldnt it?

I've replaced the old isolator valve as well, only think in line is the new full bore one!!

Any ideas?

Cheers
Chris

 

if theres no water coming from the hot or very little its more than likely airlocked,like dingle said above,open the hot,then put the palm of your hand over the outlet then open the cold,do this for about 10 secs,unless theres a double check valve in the tap somewhere which the hot water pressure cant open.

 

is the hot water pressure at other taps in your house fine? if so then id say you need a non return valve, not likely to be air locked if the pipe going to the basin comes off of one connected to pipe that goes to another tap? ie kitchen, and being that its being fed from upstairs to downstairs you should have effiecient enough pressure, so all i can see it being is the tap not having a bs mark, as all new mixer taps with a british standard have metal going through right to the end inside the tap to solve the problem of things like the cold pushing the hot back up the pipe if they are seperated inside the tap till the end then one pressure cant push the other pressure back and it mixes at the outlet, which i dont think your tap has, it says nothign about a british standard in that ebay listing, so fiting a non return valve should solve this problem if thats the case

 

There is hot water coming out, loads more than just a trickle, but not enough to be suitable for use. Definitely not an airlock (i think), when I first turned it on it coughed and spluttered then came to life. Got a mate popping over tonight to test teh pressure (?) so we can see what is actually coming out of the pipe.

Any ideas where I can buy a low pressure tap from?