Toilet won't stop filling - Siamp Valve

[Andy46]

Hi,

My toilet suddenly stopped filling. I checked the following video on youtube and replaced the diaphram, which had a hole in it.

https://www.youtube.com/watch?v=fd3-nyqxD_A

This resolved the problem for about a week, but now I have the opposite problem in that my toilet won't stop filling up. Any ideas please?

Also, what is the float actually supposed to do, I would guess if i lift this up manually then the water should stop but it doesn't, the float doesn't seem to do anything.

Thanks

[bungeejumper]

Sounds like your diaphragm isn't fitting properly. (Or did you buy a low pressure one when you needed high pressure?) Maybe just invest a tenner in a new float valve?

That is, if you can find a new float valve. The last time I replaced one (it was leaking), all I could find locally were float cup systems, which are vertical gizmos that don't have a float lever arm at all. It was an hour's job to replace, because the cistern has to be drained and the inlet pipe temporarily disconnected. But has been very good, very quick to fill and very quiet.

BJ

[seagles]

The float is there to stop the water entering the system at a predetermined level. If yours doesn't stop the water then you have a problem with the float mechanism.

[monabri]

As the water level in the tank rises, the float rises. The float is attached to the inlet valve, probably by a plastic forked arm (see video at 25 seconds). As the float rises, it pushes on the arm which pushes on the siamp valve and closes it. It could be your float is damaged or you haven't adjusted the float level such that it rises high enough to cut off the water. If the plastic arm mechanism isn't connected, the valve won't shut!

Make sure the arm is connected and operate it manually to check that as the float rises, the water inlet valve ( siamp) shuts off.

[bungeejumper]

Sorry, should have added. The mystery is that you had a week's good performance before yours suddenly went wrong. I'll hazard a guess that you've got a bit of scale in the valve somewhere. Well, either that, or else the screw adjuster for the float level has come loose and it's gone out of adjustment. (There should be a lock nut somewhere.)

But if not, you're better off replacing the valve. You can clean them, but it's a delicate faff, and they're never quite the same afterwards, and at that price why bother?

BJ

[DrFfybes]

In the original video it shows what happens if the float sticks.

Can you lift your float all the way to the top of the travel to stop the flow?

If you can and it doesn't, then take the diaphragm out and check it - might be some bits in there or a split.

If it doesn't come to the stop of the travel, then that is a different issue, probably caused by disturbing something when you changed the diaphragm

[Andy46]

Hi

Thanks for the comments.

I'm guessing the hole inlet valve needs replacing so think i'll call a plumber, ta anyway

[bungeejumper]

I'm guessing the hole inlet valve needs replacing so think i'll call a plumber, ta anyway

Terribly simple DIY job, especially if you've got an isolation valve somewhere on the adjoining pipework?

(Just turn the screwhead slot by 90 degrees and your water feed is off.)

BJ

[monabri]

How to change the valve

https://youtu.be/oz6z24HciSg


Replacement unit about a tenner.

https://www.screwfix.com/p/flomasta-bot ... alve/5527f

[jfgw]

With these servo valves, the float operates an arm which closes a tiny hole. This allows water pressure to build up behind the washer which closes it. If you lift the float manually, there is a delay before the water shuts off.

Make sure that it is screwed together tightly as a small leak can stop it from working. It may help to pull it apart first and give it a clean.

If that doesn't fix it, I, personally, would replace it. I like the Fluidmaster ones with a brass shank, https://www.screwfix.com/p/fluidmaster-bottom-entry-pro-bottom-entry-fill-valve/81274.


Julian F. G. W.

[quelquod]

I'm guessing the hole inlet valve needs replacing so think i'll call a plumber, ta anyway

Terribly simple DIY job, especially if you've got an isolation valve somewhere on the adjoining pipework?

(Just turn the screwhead slot by 90 degrees and your water feed is off.)

BJ

Yes wonderful things, I always fit them all over the place just in case. Last time I needed to use the one in our en suite I turned the screw and the seal failed and had me running for the stop cock (as usual inconveniently situated in a tight corner under the kitchen cupboards). 2 hours to replace the isolating valve with no space to turn the spanner on top of the original job.

[jaizan]

Yes wonderful things, I always fit them all over the place just in case. Last time I needed to use the one in our en suite I turned the screw and the seal failed and had me running for the stop cock (as usual inconveniently situated in a tight corner under the kitchen cupboards). 2 hours to replace the isolating valve with no space to turn the spanner on top of the original job.

I often get a dribble or 2 from isolating valves after turning them, but it never turns into a full scale leak and always stops pretty quickly. Having seen that, I wouldn't install them in a confined space.

As for the toilet filling issues raised in the original post, this is about as simple as plumbing ever gets. I'd start by taking the top off the cistern and see if the valve shuts off after lifting the float. If yes, adjust it to stop at the right point and tighten the lock nut. If not, check the diaphragm.
Needs just a little aptitude.

[johnstevens77]

Sorry, should have added. The mystery is that you had a week's good performance before yours suddenly went wrong. I'll hazard a guess that you've got a bit of scale in the valve somewhere. Well, either that, or else the screw adjuster for the float level has come loose and it's gone out of adjustment. (There should be a lock nut somewhere.)

But if not, you're better off replacing the valve. You can clean them, but it's a delicate faff, and they're never quite the same afterwards, and at that price why bother?

BJ

I agree, just replace it. I tried to repair one once and it was not worth the bother.

john