New mixer tap on bath but low cold water pressure.

[JonnyN15]

Fittted a new bath the other day along with a new mixer tap. I had to extend the old copper pipes and I used the 22mm pushfit items to do so.

The hot water feels perfect but the cold is low compared to how it was on the old taps which had seperate heads.

The hot water comes from a cylinder next to the boiler and the cold comes from a tank in the loft fed from the mains.

First thought was an airlock but using the technique someone said before about using the kitchen tap to force the water back up the pipework to free the air seemed to make it a little better but it's still not what I'd expect.

Then I read newer taps are designed for mains pressure but the taps list operating range of .5 bar - 3 bar which I imagine the gravity fed cold should make since it's up another level.

The common problem I read as low hot pressure due to the mains cold being too powerful so fitting a valve cured this, doubt this is the case with myself.

These are the taps.
http://www.victoriaplumb.com/Taps/C...Bathroom-Tap-Range/Matrix-Bath-Mixer_358.html

Cheers
Jonny

 

[denso13]

0.5 bar is around 5m in height. If your bathroom is upstairs and the cistern is in the loft you probably won't have this. Probably nearer half what you need.

 

[JonnyN15]

Thanks for that mate. I've read there's a pump you can get fitted for hot water, can this be used to boost my cold water?

 

[Whitespirit66]

Getting the right taps for gravity systems is important. You probably need low pressure bath deck mixers, with a min requirement of 0.1 or 0.2 Bar.

Eg. -

http://www.tapstore.com/bathroom-ta...ted-bath-fillers/hero-bath-filler-chrome.html

http://www.tapstore.com/bathroom-ta...d-bath-fillers/bristan-blade-bath-filler.html

http://www.tapstore.com/bathroom-ta...th-fillers/hudson-reed-arina-bath-filler.html

Taps with traditional washered valves are usually more successful with gravity systems than newer ceramic disc versions.

 

[joe-90]

Why not take a feed from the mains before it reaches the tank?

 

[Whitespirit66]

Why not take a feed from the mains before it reaches the tank?

Maybe because he doesn't want the additional problem of unbalanced supplies, or having to pull his bathroom apart to re-pipe.

I think you need to go on a short course for plumbing Joe.

 

[JonnyN15]

The bathroom is still not bolted down properly so i could take a feed but it would be a bastard as the main feed is the most rightly pipe of 4 in a row. They are also behind the toilet which is annoying.

parents seem ok with how quick the bath fills when using both taps so they will probably just leave it as is rather than buying new taps for them to possibly not help much.

 

[CBF]

as Whitespirt said if you connect the cold to the main you will have unbalanced supplies which could cause more problems, really if the hot supply is ok then the cold should be as well as they should be the same pressure, are you sure you haven't still got an airlock in the cold or has some crap gone down the pipe when you drained the roof tank

 

[JonnyN15]

Not sure really. Cant get the hose connection, for a garden hose, onto the larger head of the bath tap securely enough.

How would i remove any crap that is stuck between the tank and taps?

 

[joe-90]

Why not take a feed from the mains before it reaches the tank?

Maybe because he doesn't want the additional problem of unbalanced supplies, or having to pull his bathroom apart to re-pipe.

I think you need to go on a short course for plumbing Joe.

Where's the pressure for his hot supply coming from? He can make a connection in his loft rather than in his bathroom.

 

[Whitespirit66]

Why not take a feed from the mains before it reaches the tank?

Maybe because he doesn't want the additional problem of unbalanced supplies, or having to pull his bathroom apart to re-pipe.

I think you need to go on a short course for plumbing Joe.

Where's the pressure for his hot supply coming from? He can make a connection in his loft rather than in his bathroom.

Yes, he can make the connection in the loft, but mixing mains cold and gravity hot can create problems in mixer taps fitted in the house. Your suggestion would solve one problem but possibly create another.

There's always more to plumbing than you think Joe.

To the OP -

Unless you have 5 metres height difference between the top of the cold storage tank and the mixer, your tap won't perform properly.

You can help the flow to the tap by; 1)not having isolation valves on the feeds as these restrict flow 2)making sure that the tap connectors aren't kinked and don't have tight curves 3)taking Joe's suggestions with a large pinch of salt.

 

[joe-90]

So why does he have a high pressure on his hot tap then? That's what I'm asking you.

 

[Whitespirit66]

So why does he have a high pressure on his hot tap then? That's what I'm asking you.

He doesn't have high pressure on his hot, it has higher flow than the cold. As to why it's higher on one than the other - it's anyone's guess - air lock, crud in the pipe, isolator not fully on, tap design, etc, etc, etc.

Unless he has more than that magic 5m of head, one of the above problems, or a combination of several, may give him the symptoms he has. With adequate head a slight restriction, etc wouldn't be so critical.

 

[denso13]

Yes, probably better flow rate at the hot tap, for whatever reason, but pressure will be the same.

 

[joe-90]

So why does he have a high pressure on his hot tap then? That's what I'm asking you.

He doesn't have high pressure on his hot, it has higher flow than the cold. As to why it's higher on one than the other - it's anyone's guess - air lock, crud in the pipe, isolator not fully on, tap design, etc, etc, etc.

Unless he has more than that magic 5m of head, one of the above problems, or a combination of several, may give him the symptoms he has. With adequate head a slight restriction, etc wouldn't be so critical.

He has a considerably higher flow from the hot tap yet the hot water travels all the way down to the tank near the boiler where it's heated indirectly then all the way back up to the bathroom and out of the hot mixer tap at considerably higher output than the cold tap that simply comes down from the loft??

I think you need to do more than a short course in plumbing mate.