cistern inlet

[benpost]

its from b + q =A3189 suite, a plastic inlet thread comes out of the cistern to attach the water supply.

the pipe coming up to the cistern has a white plastic connector with a black rubber washer and gold metal nut. when i put everything in place and tighten the nut (taking care not to cross thread), its still diffficult to tighten it up, and after a few turns with a spanner, it doesnt look straight.

with the water on theres a very slow leak, a little drop of water seeping from under the nut occasionaly.

now is the problem using a metal nut on a plastic thread? the washer looks in good condition. any help appreciated.

[BigWallop]

the pipe coming up to the cistern has a white plastic connector with a black rubber washer and gold metal nut. when i put everything in place and tighten the nut (taking care not to cross thread), its still diffficult to tighten it up, and after a few turns with a spanner, it doesnt look straight.

with the water on theres a very slow leak, a little drop of water seeping from under the nut occasionaly.

now is the problem using a metal nut on a plastic thread? the washer looks in good condition. any help appreciated.

Wrap the thread with PTFE (plumbers) tape. Four or five full turns around the thread should be enough. Or get a softer seal washer, or double it up, in the connector.

[John]

I beg to differ - the thread should not be contributing to the water tightness. Perhaps the wall thickness of the cistern is not consistent - so the idea of doubling up the washers is a good idea - preferably on the inside.

[The Medway Handyman]

Does the connector look like this?

> with the water on theres a very slow leak, a little drop of water

Its the alignment. Common problem IME.

The best way to fit these IME is to slacken off the nut holding the float valve inlet into the cistern. This gives enough flexibility to line up the threads exactly. If they are not lined up exactly the metal nut will try to cut a thread on the plastic inlet thread & it will drip.

Lined up exactly the metal nut can be tightened up by hand & a final 'nip' with a spanner seals it. A smear of LSX helps.

[Dave Plowman (News)]

Fernox LS-X is your friend.

[benpost]

medway handy man you were correct, i'm glad this is a common problem as my dad who has been helping me, had a right go about me cross threading it!

in the end we had to unwind the plastic nut above, to restore the thread, and attach the metal nut with the cistern moved.

the re attach the water inlet on the other corner of the bend which is a push fit one.

i would guess a metal thread would be a better idea here??

[The Medway Handyman]

Glad you got it sorted. If I change a ball/float valve I invariably use a flexible tap connector just to avoid the problem & make life easy.

Older ball valves were brass and you didn't get this problem.