Sealing off isolation valve

[Erico19]

Hi,
The isolation valve feeding my toilet cistern was leaking. After considerable effort, I was able to lift up the cistern to put an O-ring washer around the top of the inner circle referred to with an arrow in the attached image. Unfortunately, when I let the water through, there was a burst leak. Should I use a flat-ring washer instead? If so how can I get the right size?Should I put the ring at the top or push it down?
A friend suggested using also a jointing compound along with a PTFE tape; If a washer is enough, I won't buy these products

Thank you.

 

[ShaunCorbs]

You can use a small amount of silicon I’m guessing you’ve re used the old washer that seals to the cistern?

 

[Erico19]

Thank you, ShaunCorbs, for your response. Yes, I have kept the same washer on the bottom side of the cistern and at the top of the valve.

I conclude that neither PTFE tape nor jointing compound will fix it. Instead, I will need to add silicone at the edge of the washer.

 

[ShaunCorbs]

Thank you, ShaunCorbs, for your response. Yes, I have kept the same washer on the bottom side of the cistern and at the top of the valve.

I conclude that neither PTFE tape nor jointing compound will fix it. Instead, I will need to add silicone at the edge of the washer.

Not at the edge about half way in on the washer etc

 

[Erico19]

Not at the edge about half way in on the washer etc

Thank you very much. Tightening the washer while adding silicone on it stopped the leak. Apparently, I had overtightened the washer, which caused the float ball to shift to the side of the cistern. When the cistern fills up, the internal water flow doesn’t stop completely (water drops) because the friction between the float ball and the inner wall of the cistern prevents it from moving up freely. My toilet system is similar to this one: Replacing a Toilet Tank Float Valve. - https://www.instructables.com/Replacing-a-Toilet-Tank-Float-Valve/. I’m wondering if there’s a quick fix without having to redo the work, now that the silicone has been applied, especially since there’s barely enough space to reach the washer. Thank you."

 

[Erico19]

Thank you very much. Tightening the washer while adding silicone on it stopped the leak. Apparently, I had overtightened the washer, which caused the float ball to shift to the side of the cistern. When the cistern fills up, the internal water flow doesn’t stop completely (water drops) because the friction between the float ball and the inner wall of the cistern prevents it from moving up freely. My toilet system is similar to this one: Replacing a Toilet Tank Float Valve. - https://www.instructables.com/Replacing-a-Toilet-Tank-Float-Valve/. I’m wondering if there’s a quick fix without having to redo the work, now that the silicone has been applied, especially since there’s barely enough space to reach the washer. Thank you."

Sorry, it's me again 🙂

I opened the isolation valve under the cistern yesterday morning. The toilet wasn't used, but I flushed it twice—much less than in previous days.

This morning, I was horrified to find a leak from the ceiling in the room below. I checked the upstairs toilet, and everything was dry. Purposely, I left the cistern half full last week and there was no leak. It did rain, however, for most of the day yesterday and overnight. I checked the attic, and everything seems dry. The fixed toilet is on the brick side of the house, so I'm struggling to identify the cause of the heavy ceiling leak this morning. Any tips would be greatly appreciated. The boiler was serviced this week by the same company.

I've closed the isolation valve under the cistern since the morning. If it were an internal pipe leak, the leak wouldn’t stop.

Coincidentally, the ceiling leak occurred when it rained heavily yesterday and when I had the isolation valve open all day. Please note that I checked during the day, and the water feed into the cistern stopped.

The leak in the downstairs room was clean water. It occurred at the outer corner of the toilet drain-waste vent system compartment running to the ground.

Thank you.

 

[Chuck]

Wrap several layers of toilet tissues around the suspect valve/joint and hold in place by tying with a piece of elastic, e.g. cut open an elastic band. This will allow you to rule the isolator and nearby joints in or out.

What direction does the outside wall face and what direction was the rain coming from? Can you post a couple of pictures of the outside wall?

BTW, I haven't got the time right now to read two dozen posts to figure out exactly how you fixed the leak between the inlet valve spigot and the isolator but I suspect you bodged it. The way I would have dealt with it would have been a new float valve with a brass spigot and, since it is corroded, a new isolator. The seal should be made by a fibre washer, no silicone needed.

 

[Erico19]

Wrap several layers of toilet tissues around the suspect valve/joint and hold in place by tying with a piece of elastic, e.g. cut open an elastic band. This will allow you to rule the isolator and nearby joints in or out.

What direction does the outside wall face and what direction was the rain coming from? Can you post a couple of pictures of the outside wall?

BTW, I haven't got the time right now to read two dozen posts to figure out exactly how you fixed the leak between the inlet valve spigot and the isolator but I suspect you bodged it. The way I would have dealt with it would have been a new float valve with a brass spigot and, since it is corroded, a new isolator. The seal should be made by a fibre washer, no silicone needed.

Thank you for the tip. The joint pipe which outs the water from the tank was loosely connected.