What's wrong with my tap?

[ntl142]

This video is the hot water tap in one of the bathrooms, and it spits/hisses when turned down low. None of the other hot taps do this. It's not the furthest from the boiler. The plastic supply pipe comes up from under the floorboards to this tap, I don't think it's run through the loft.
It's a single story house with combi boiler.

It starts off on full flow, and as I gradually turn it down you'll see it spit/hiss. Needs sound on.

http://sendvid.com/rpk7ivj1?secret=cdc801a0-6abd-4b2a-8330-0248106b9f85

Is it a fault with the tap, or something else? I've tried disassembling the tap to clean out the insides and check seals etc, but even after soaking it in plusgas for a week it still wouldn't budge - something will snap if I put any more force through it.

Thanks.

 

[Nige F]

Have you got an isolating valve in the feed to the tap -try partly shutting it. Then if no different, fully shut it and take the tap out. Lay it on the floor (mat ) and get a big open end spanner ( or adjustable) on the tap body. One foot on the tap and one on the spanner. That's what we used to do when fitting new taps - "break" them and then nip back up again or they wouldn't come apart later for re washering. Like yours.

 

[ntl142]

Hi, thanks for your suggestions. I've tried adjusting the isolating valve and it does have an effect, but the tap still spits and hisses. The pipe fittings are grey Hep2O and I've heard they sometimes don't like to be disassembled, and need a special tool. Any thoughts on that?

I've tried disassembling the tap by putting a spanner on the cartridge nut, and a large adjustable on the spouty bit. I'm sure the spout will snap off if I put more force on it! I'm fairly handy with spanners on cars so have a feel of what is tight and what isn't.

I took the handle off and looked inside, and there's obvious corrosion. I've filled that 'chamber' with plusgas for a couple of weeks and still no joy.

I guess I'm asking is it most likely the tap causing problems, or something else? I don't want to replace the tap and find something else was causing the problem, so any advice appreciated there! Thanks.

 

[ntl142]

Here are a few photos of the tap plumbing. There are isolation valves which is a good start. To remove the tap, is it simply a case of undoing the brass/bronze nut on the threaded boss coming out of the bottom of the tap? Does this nut rotate independent of the rest of the pipework, i.e. can I isolate the supply, undo the brass/bronze nut on the threaded part of the tap, remove the black plastic nut, and remove the tap? Is it that simple? No messing with the plastic pipework?

 

[terryplumb]

Yes , you have pretty much got it !! But you will need a special basin spanner to reach those awkward nuts

 

[ntl142]

That's great, thanks for the tip. I'll have a go at getting the tap off and stripping it down in a bench vice. Hopefully something simple inside there is wrong/old and I don't start having to look at pipework and boilers...