Plumbing - Leak from Cistern

50Twuncle

We have a weird leak from our toilet cistern that only drips water when the flush is used (ie During the refill) - the leak appears to be from the filling pipe entering the cistern - I have tightened up the nut - with no effect !!
Any ideas why ?

Seronera

Its a bad seal or cross threaded.rather than just tighten it you ought to remake the joint using some PTFE tape....not forgetting to isolate the water supply first of course

50Twuncle

Seronera wrote: »

Its a bad seal or cross threaded.rather than just tighten it you ought to remake the joint using some PTFE tape....not forgetting to isolate the water supply first of course

It is from the top nut - plastic - the one that connects to the flush valve - so I imagine that the flush valve needs replacing anyway ?

Seronera

Ah yes,different nut. That one has a rubber washer inside the cistern. They do leak from time to time,but I usually just remove it and put polyurethane sealant..not silicone..round it and put it back.usually works

Jonesya

Have you opened the cistern up and watched it as its flushing and refilling?

To get a leak ONLY during refilling is a bit odd - the only time I've seen that is when there's a problem with the cistern valve and its spraying water around inside the tank, rather than cleanly down into the bottom of the tank. The spray then leaks out through gaps, fixing holes etc.

Is it a side mounted valve, could be the forces on it when the ball drops during a flush is enough to open up the joint slightly causing a slight leak.

50Twuncle

Jonesya wrote: »

Have you opened the cistern up and watched it as its flushing and refilling?

To get a leak ONLY during refilling is a bit odd - the only time I've seen that is when there's a problem with the cistern valve and its spraying water around inside the tank, rather than cleanly down into the bottom of the tank. The spray then leaks out through gaps, fixing holes etc.

Is it a side mounted valve, could be the forces on it when the ball drops during a flush is enough to open up the joint slightly causing a slight leak.

Yes and I agree - I think that we need a new valve..