Persistent leak from Fluidmaster bottom entry valve

7 Apr 2006
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United Kingdom
I have a Fluidmaster bottom entry float valve fitted to my cistern. The issue I cannot fix is that the central column is effectively two pieces (so you can adjust the height of the valve to accommodate various sizes of cisterns) and I am suspecting that a leak is escaping through the join around the two respective mid-sections even though there is a collar to supposedly compress the pieces together and presumably create a water tight fit.

I have tested it with the cistern dry and by using a pencil under the valve arm effectively isolated the valve to an off position yet water still creeps into the system for somewhere close to the collar. I have replaced the entire unit, and although initially better, within weeks it has deteriorated and an escape has reappeared.

The system is only gravity fed from the loft to an average height upper floor... but do I need to replace the washers so it can sustain a higher pressure or am I missing something more fundamental ? :?:
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You need to contact the manufacturers for detailed advice.

I specialise in boilers so my knowledge of bathroom equipment is peripheral.

However, some of these valves are designed for mains pressure supply and will not turn off with a low pressure feed.

Look at the instructions and see what they say and then check with the manufacturers.

You need a low pressure diaphram (red in colour) that fits in the top of the fluidmaster. The one you have is for high pressure and will not shut off if it's fed from a tank. It is a 60 sec change when you get the right part. Instructions on how to change it are in the instructions for the fluidmaster.
You usually get both diaphrams in the pack when purchasing new....! Have a look for the bag it came in, its probably lurking there. :D

Agile your being very direct, without all the crap, you almost sound like a good bloke...... :LOL:
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Not now you don't, I think they've cottoned on to the spare parts racket
and will sell you one for a fee. They are on a bubble and card pack.
Not now you don't, I think they've cottoned on to the spare parts racket
and will sell you one for a fee. They are on a bubble and card pack.
Hi there, I'm a new member to this forum and found this thread through a search string on google for this part.
I have been pushing the plumbers (B&K Plumbers in South East UK) to repair my faulty bottom entry valve on my cistern. I have a 5 yr old new build and the 1st one I had went on my ensuite toilet within about 4 years. It went undetected until downstairs complained of a leak. It was dribbling out from the connection between the valve and the brass/copper supply pipe. It looks like it was the way in which the metal pipe connects to the bottom entry valve and the fact that metal and plastic don't seem to work too well. Something about a tight seal using a plastic washer on a metal pipe and too tight and it will crack the plastic, not tight enough and it won't seal! :0(
About 9 months after it was replaced, it went again!! I had replaced the carpet and most of the ensuite as it had leaked under the boxed in toilet parts as well as under the bathroom tiles!
So I quoted the plumbers the Services and Goods Trade Act and told them they had to pay for the damages this time (another carpet and tiles and re-decorating)
You can imagine that I am not too keen on doing this all again in another few months time.
Is there anything I can do to prevent this? Any tips on connecting this bottom entry valve to the metal water supply pipe?
Is this a common problem with metal/plastic connections? Should I go for a different type of toilet.
Thanks for any advice - have been without ensuite for almost 8 months and don't want to go through this again!

Bit naughty of you to hijack a post.

Anyway track down a fluid master bottom entry float valve that comes with the brass tail instead of the plastic one, no probs then.

Thanks Rico,

Apologies for hijacking the post

Thanks for your comments and will be looking for a brass based fitting!!



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