Leaking bottom inlet on toilet cistern.

[Bogart]

Just fitted a new WC and all okay except I cannot get the bottom water inlet to seal. It is a Fluid master setup. It drips from between the cistern base and the plastic nut not between the nut and the thread. It came with a flat washer, have even tried 2 washers, came with a spare in case cistern had side entry too. Now some Fluidmasters come with conical washer, like those used to seal the cistern to the pan, not sure how it is decided whether flat or conical, not what to use to overcome this problem.

 

[Rob Foster]

I always thro away the foam donut and get the rubber one
more reliable and re usable
centralheatking

 

[ShaunCorbs]

Con washer always

And is the cistern flat around the inlet hole eg no bumps / lumps in the casting

 

[steadyon]

Conical washer inside cistern with narrow end facing down. This makes the water tight seal between valve and cistern, and also centralises the threaded stem of the valve in the hole in the cistern. On outside of cistern, no need for a washer, just the white plastic nut.
Make sure you have a fibre washer in the connector which secures the inlet pipe to the bottom of the inlet valve, unless you are using a flexible hose to attach, in which case there should already be a rubber washer inside the flexi connector.

 

[Ben-gee]

As shaun says, check base for lumps/bumps in the glaze - I would add to that check for hairline crack.
Conical is best but to be honest you should be able to seal against the 0.03bar head with a flat washer.
For fail safe run a bead of stixall/ct1 under the flat washer first and then tighten as usual.

 

[Bogart]

I always thro away the foam donut and get the rubber one
more reliable and re usable
centralheatking

Hi It is the water inlet not the cistern to pan joint.

 

[Bogart]

Con washer always

And is the cistern flat around the inlet hole eg no bumps / lumps in the casting

Looks to be fine even so I ground out a couple of minor bits and feels smooth enough.

 

[Bogart]

Can you buy the conical washers separately? Off to TS to get a tube of Stixall.

 

[ShaunCorbs]

If it’s smooth how tight are you doing the nut up ?

 

[Bogart]

If it’s smooth how tight are you doing the nut up ?

Started at finger tight, then a bit more ,and then a bit more .

 

[Burger]

Is it sat flat? I’ve had a few cisterns recently where the hole was making the rubber washer curl at the side slightly due to poor manufacturing.

 

[Bogart]

Is it sat flat? I’ve had a few cisterns recently where the hole was making the rubber washer curl at the side slightly due to poor manufacturing.

Is a cheap suite and with good reason. The hole is not particularly level, have removed lumps and bumps but is I suppose on closer inspection expecting a single washer to work hmmm Hopefully the Stixall will sort it.

 

[Ben-gee]

It will!

 

[Bogart]

It will!

Filled the slight unevenness in the casting with Stixall. Taking note of info on tube ie full curing 24 hrs per 1.5mm depth with attempt a fix sometime tomorrow. One should not have to do this but in this case the maxim " you get what you pay for" is totally spot on.

 

[Ben-gee]

Ignore that, you can fill the cistern immediately.

 

[Tim S]

Fit the fill valve into the cistern and before you put the plastic nut on and tighten it run a bead of clear silicone into the gap between the hole in the cistern and the thread of the fill valve. Fit the plastic nut and tighten sufficiently to compress the washer at the base of the fill valve inside the cistern but don't over tighten it.

 

[Ben-gee]

The hole is the cistern where the tail of the valve goes should never see water.
The seal is between base of cistern and flange on bottom of fill valve. This is always possible to do, sometimes sealant is required due to poor moulding of ceramic.

 

[Bogart]

Give that man a medal. Stixall worked a treat. Never bought or used befòre. One is never too old to learn thank you.

 

[Coby kenny AGUILAR]

Measure the thread next time,

I've had a couple of cheap close couple pans from SF and the thread on the flush valve is too long, so the Cistern doesn't sit flush with the pan

 

[Ben-gee]

Glad you got it sorted. You can literally give me a medal on my post if you like!