Tap washer problem?

[Kit]

I am not a plumber (as will soon become all too obvious) so does anyone have a simple answer as to why the water comes out OK when I first turn on my hot tap, then after a few seconds it slows down to a trickle. If I turn it off and then on again it sometimes helps. It's quite variable - some days it works without a problem.
What's happening and why?

[Mandible4]

You're right in thinking that this problem is to do with the tap washer... a small hard rubber disk that lives inside the body of the tap. There are two main possibilities: 1 The washer has perished and swelled in size so that it is restricting the flow, even when the tap is full on. or, more likely, 2 The retaining screw holding the washer in place inside the tap has come loose or snapped off so that the washer moves about inside the tap body giving this variable effect you describe. To fix 1, you just need a new washer (two main sizes in UK. One for bath taps, one for basin taps). To fix 2 you will need a new tap insert.... probably have to buy these in pairs complete with the tap tops... typical B & Q offering. Good news is that replacement taptops often come with several different screw insert pieces so you can fit them to your existing tap bodies. Then it's just a matter of switching off the water supply, and/or draining the hot water tank down depending on whether you have a local isolator near the tap, removing the existing tap top and unscrewing the insert. Check for either 1 or 2 and replace as necessary. Of course, if cutting of the water is a major drama you're more or less forced to assume that you will need a whole insert before you can find out for sure.... unless you happen to live next door to a DIY store. Good Luck M

[Kit]

Thanks, Mandible4... I think.... :) great scott, sounds like it's going to be a major undertaking whatever the cause, but at least I understand a lot more of what's going on. Better do it quick before it gets any colder!

[charlieroker]

I disagree. Sounds like you are sharing a tank. That's why it works sometimes and not others. It also explains the works fine to start with (ie with pressure) and then trickles after a while( ie withour pressure). Get a mate to discover how your systems works. Is it an immersion tank or a pressured system?

[Kit]

Sharing a tank? (Who with?!) No idea about the kind of system it is - there's no immersion heater, it runs off the boiler, and has a pump with a motorised valve that gave us some problems several years ago. If it's a problem with the tank, wouldn't that affect the hot tap in the kitchen as well? It's only the bath tap that's affected. It usually slows down to a trickle within about 10 seconds of turning it on - does that sound like the sort of pressure problem you mean? What can be done about it if it is?

[ukkid76]

Sounds like an air lock problem to me try pumping mains water up the hot tap in the bath for a very short time (10 20 seconds) and see what the flow is like then or better still why not employ a professional to sort it out for you!!!!