Low mains pressure

[Maisie's dad]

Hi there

Happy Christmas to you all.

Water pressure was low in kitchen tap and bathroom taps (bath and basin. The stopcock wasn't fully open so I opened it fully. The pressure is now fine, except on the bath cold.

Any idea what the problem is and how to fix it please?

Thanks a lot

Stuart

 

[JohnD]

Assuming you mean that all the cold taps are fed off the water main, not off a tank in the loft (confirm this), you will almost certainly find the cold water pipes are 15mm.

Sink and basin taps are designed to run off a 15mm pipe, so given good pressure will squirt out quite hard.

Bathroom taps are designed for 22mm pipes (and have bigger waterways inside them. So the same amount of water (all a 15mm pipe can supply) will come out of this bigger tap at a lower pressure.

If you time how long each tap takes to fill a bucket, you will probably find the bath tap takes about the same time as the others.

There is a chance that the incoming water main from the street to the stop cock is in 25mm plastic pipe (or 3/4" steel) so it would be possible to increase the pipe size all the way to the bath. unlikely to be worth the effort, though.

 

[ChrisR]

So the same amount of water (all a 15mm pipe can supply) will come out of this bigger tap at a lower pressure.

No, at a lower SPEED. Pressure is identical.

 

[Paul Barker]

If bath cold is off storage tank that's your answer.

If not and you are complaining about low flow when running a bath, don't forget the storage tank is refilling full pelt to replenish the hot water cylinder, so the demand from the mains is shared. If that mains is restricted say with an old lead pipe slightly squashed underground, it ain't going to get any better until you deal with that.

 

[gazthepottertonengineer]

sounds to me like you could have a bit of an air lock on your cold water supply from the tank because if the mains wasnt turned on properly and the cold water was being used then the cold water could have been coming out of the tank quicker than it was going in and air could have got into the pipework

 

[Slugbabydotcom]

If you have flexi pipes to your bath it is possible that the one feeding the cold is kinked

 

[Maisie's dad]

Thanks a lot, I'll check those points. Reason I'm trying to solve this is because I want better pressure from the mixer shower above/and part of the bath taps and I assume if I can increase the pressure to the bath cold I'll get my more powerful shower.

Thanks again

 

[Maisie's dad]

Thanks a lot, I'll check those points. Reason I'm trying to solve this is because I want better pressure from the mixer shower above/and part of the bath taps and I assume if I can increase the pressure to the bath cold I'll get my more powerful shower.

Thanks again

 

[Maisie's dad]

Hi again

Right I've found a shower pump tucked away in the cupboard that feeds the bath cold and hot. Switched it on and great, pressure's fine. Only thing is it seems to only work for 5 minutes and then stops. Doesn't seem to work when the central heating is on and sometimes responds (works) when I tap the cold in end! It's fed by the cold storage tank.
Any ideas please?

 

[ChrisR]

Pump is clearly suspect - what else can we tell from here!

 

[Nige F]

If it`s a Start Turner pump ,you should be ok. for spares.......owt` else and you might as well renew complete

 

[Maisie's dad]

thanks for replies it's a B&Q job something like a showerforce one I can't remember the name now. Black and yellow plastic with 4 flexi pipes coming off it