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Dec 31, 2022
6
2
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london
Member Type
DIY or Homeowner
My cistern kept overflowing randomly was told it was probably caused by the bottom filling valve failing I purchased one and
cistern valve.jpg
a plumber fitted it and tested it and all seemed well, we where away for a couple of weeks and came back and there was no evidence that it had been overflowing but after using the toilet for a number of times it seems worse than before! the level of the water in the tank is set at about 1/2 below the overflow pipe. the feed to the cistern is from a header tank and not the mains, it is slow to fill the cistern. Any ideas?
 
With a gravity feed you are better off with an “old fashioned” float valve- it will be quicker to fill than an equilibrium valve and is usually easily repaired.

However; if yours is not shutting off there could well be some debris obstructing the diaphragm seal - this is easily cleared using a mug as described on box/instructions.

Do you have an isolation valve to this toilet? Things can be improved if this is a full bore valve rather than a regular bsll-o-fix type.

Pictures of you set up and inside cistern would help.
 
With a gravity feed you are better off with an “old fashioned” float valve- it will be quicker to fill than an equilibrium valve and is usually easily repaired.

However; if yours is not shutting off there could well be some debris obstructing the diaphragm seal - this is easily cleared using a mug as described on box/instructions.

Do you have an isolation valve to this toilet? Things can be improved if this is a full bore valve rather than a regular bsll-o-fix type.

Pictures of you set up and inside cistern would help.
Here's my setup had been working for over 20 years without a problem
 

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Check the float isn’t sticking to the side of the cistern and let it come up to level with the cistern lid off. Put the lid on and then see if it fills and overflows.
 

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