Leaking slow fill valve in toilet

[pcdj]

Our toilet's recently started leaking. A picture of the of the slow fill valve that's installed is below.

With the float fully raised, water still trickles down the plastic outflow pipe to the right of the foreground of the picture. It's not much, but it's noticeable enough.

I've taken the valve apart and inspected the rubber diaphragm, which appeared in good condition. I've also cleaned all accessible parts of gunk and put it all together again, which seemed to make a small improvement at first but then the leaking returned. There's a small rubber block just above a pin-hole, which sits above the diaphragm, and which I understand plays a part in the unit, but again it seems damage-free.

There don't appear to be any other serviceable parts inside.

I'd prefer not to have to replace the entire unit as this would involve removing tiling around the bottom of the toilet in order to get access to the inlet pipe. I can however easily access the shut-off valve (it's all I have access to below the cistern).

Does anyone know what I might be missing in terms of the cause of this? I can literally raise the pivot arm as high as it can go and the trickle doesn't stop.

 

[AGAS]

I'd prefer not to have to replace the entire unit as this would involve removing tiling around the bottom of the toilet in order to get access to the inlet pipe. I can however easily access the shut-off valve (it's all I have access to below the cistern).

are you sure it can't be separated at the stem inside the cistern

 

[pcdj]

I'm not sure, no. It's very difficult to tell what's going on underneath the cistern as there's so little access. I can just about fit a screwdriver into the available gap and reach the shut-off valve, but even that's a squeeze.

I'm worried that if I attempt a removal I won't be able to replace it without removing the tiling.

 

[polesapart]

Ideal Standard? Then as AGAS above.

 

[pcdj]

Ideal Standard? Then as AGAS above.

There are no identifiable marks on the unit, so I can't tell. I thought it was Armitage Shanks, but the housing is slightly different from pictures I've found online.

In any case, are you guys implying there's some sort of captive nut underneath the cistern? I don't quite understand how it can be removed "at the stem" - there's a nut holding the stem down to the bottom of the cistern.

 

[HERTS P&D]

This is the problem where people want everything hidden. It may look good for a couple of years but when maintenance is needed is when the problem starts.
It looks like tiles will need to be removed to access the bottom of the cistern to remove and refit with a new float valve. (Fluid master brass shank)

Andy

 

[pcdj]

It looks like tiles will need to be removed to access the bottom of the cistern to remove and refit with a new float valve. (Fluid master brass shank)

Andy

The two users above appear to disagree with you?

 

[HERTS P&D]

I can guarantee you that this float valve is fixed through the cistern and there is a nut underneath.

Andy

 

[Alec_t]

I'm not familiar with that particular valve, but the one I have (Torbeck) uses two rubber seals. The first is only about 3mm diameter and closes off a tiny pilot valve when the operating arm rises. The second is a diaphragm about 30mm diameter which is operated by water pressure to close the main inlet valve when the pilot valve closes.
If the mechanism in your valve is similar, have you checked that both seals are ok?
I've had to replace the 3mm seal a few times over the years, gaining access to it by unclipping the arm at its pivot points. That seal isn't sold as a replacement part (so far as I am aware), but is easy enough to make with a hole punch and a suitable bit of rubber sheet/mat/washer.

 

[Madrab]

Have you adjusted the float so the valve closes sooner? Looks like the float is right at the top of the valve. The float rod, back right, should be threaded and runs down through the float, as you twist the rod the float moves downwards on the rod. That then allows the float to close the valve earlier.

 

[pcdj]

I'm not familiar with that particular valve, but the one I have (Torbeck) uses two rubber seals. The first is only about 3mm diameter and closes off a tiny pilot valve when the operating arm rises. The second is a diaphragm about 30mm diameter which is operated by water pressure to close the main inlet valve when the pilot valve closes.
If the mechanism in your valve is similar, have you checked that both seals are ok?

Sounds exactly like mine. Yes I've checked both. From my original post - "I've taken the valve apart and inspected the rubber diaphragm [...] There's a small rubber block just above a pin-hole [...] but again it seems damage-free."

Have you adjusted the float so the valve closes sooner.

I haven't, but even with it manually closed (grab the pivot by the hand and pull vertically upwards as far as it goes), the unit still leaks.

 

[HERTS P&D]

Time to remove tiles and replace the float valve.

Andy

 

[gasbusters]

Some of these are impossible to get to without removing the toilet. If you cannot access the nut easily, best to call a plumber in who will have to take out the toilet and change the valve.

 

[Alec_t]

There's a small rubber block just above a pin-hole [...] but again it seems damage-free.

Well, mine looked damage-free, but it obviously wasn't. The total sealing of that pin-hole is vital: the slightest weep, e.g. due to a speck of dust or worn rubber, and the main (diaphragm) valve will leak.

 

[Stadan20]

You could replace the washer within the device , plumb centre do them ,,,, I think they are hush flow