Hot tap flow slows to dribble

[jxm28788]

Hi,

I have a problem with the hot tap on my upstairs bath. If I turn the tap on full the water comes out at a decent rate - to start with. After about 5-10 seconds it graduallys slows down to a dribble.

The hot tap on the sink seems ok, although not a great flow, but if the hot bath tap is running and I turn the sink tap on nothing comes out at all.

It didn't used to be like that and there have been no changes to the plumbing system. I think it has ocurred gradually although it's hard to say as it's a mixer tap and I usually turn both on at once. But it did definately work previously.

Any ideas as to the cause?

Thanks,

John.

 

[gas4you]

Sounds like a blockage in the cold feed to the HW cylinder.

Check that there is not some carp over the outlet in the cold storage tank in the loft.

Failing that, connect a hose from a cold mains tap, across to a hot tap, open the hot then turn on the cold tap fully.

Hopefully this will push any blockage back into the tank in the loft.

The last one I had was a dead mouse in the tank outlet. It came out so fast with the cold mains pressure I think it is still in orbit

 

[bengasman]

The last one I had was a dead mouse in the tank outlet. It came out so fast with the cold mains pressure I think it is still in orbit

Makes you wonder how long people have been brushing their teeth with water that had a corps floating in it.
Who was it that asked me why I don't like cold storage tanks?
yuck.

 

[jxm28788]

Check that there is not some carp over the outlet in the cold storage tank in the loft.

Failing that, connect a hose from a cold mains tap, across to a hot tap, open the hot then turn on the cold tap fully.

Hi, sorry for the delay, I just got back. ok, I took a look at the tank - apart from the water in and the overflow there are 2 other pipes at the bottom of the tank (one small, the other larger). Although there is some debris at the bottom of the tank the 2 holes seem clear as far as I can tell although I can't get close enough to them to stick my arm in the water and poke around.

So how do I know which cold are on mains water? is it just the downstairs one's? I guess I turn them up full blast and see which one's are really high pressure!?

The problem is that most of the taps are mixers apart from the sinks in the bathroom/downstairs toilet and those taps aren't really the right shape for attaching a hose to... I guess I'll go down to b&q and see if I can find some suitable connector.

As for the procedure, I assume I just turn both taps on full and the mains cold will overpower the feable hot water? or do I give it full cold and half hot?

 

[jxm28788]

also, could this be the problem?

//www.diynot.com/forums/viewtopic.php?t=99840

 

[jxm28788]

ok, I've done some further investiagation. The problem also seems to affect the most of the other taps, but they take longer to slow to a dribble as they seem to have a much smaller flow than the bath tap.

I've tried blasting the mains through the hot tap, but it doesn't seem to make any difference - but I don't even know if I'm doing it right...

Does it matter which hot/cold tap I do this through or does it have to be the main one that is affected?

 

[gas4you]

It has to be a cold mains tap, not the cold on the bath as this is probably off the cold tank in the loft, if it has been installed correctly.

If it is affecting all hot taps then it has got to be in a common bit of pipe to them all, so in theory any hot tap will do.

It could be in the cold fill to the HW cylinder, which will be harder to shift, as the cold mains water will probably shoot up the open vent off the HW cylinder, rather than push the pressure back up the cold fill.

You could try very temporarily capping off the open vent when you try the cold mains through the hot taps.

 

[jxm28788]

I used the downstairs feeds for the washing machine (I disconected one of the flexible pipes, then screwed the other pipe across both the hot and cold taps.

Then I turned the hot on half, the cold on half, the hot on full and then the cold on nearly full - then left it for about 30 seconds then turned them both off - no effect...

I think it's getting a bit to technical now, I'll best call a plumber before I blow something up...