Grohe concealed cistern running despite changing seal

[Jaycee]

Hi everyone and thanks for having me as a member. I hope I'm in the right place, being an amateur!
We have a Grohe old-style Eau2 concealed toilet, about 11 years old, that has started running water after it has flushed. I assumed it was the seal at the bottom of the flush valve as that had been a problem with our other identical toilet, so have changed the seal and checked that the flush valve has clicked into place properly on the flush valve seat. With some water still in the cistern after flushing I turned off the water inlet and there is no water trickling into the bowl, so am assuming the seal is not the problem. (By the way we are in a very hard water area.)

I turned the water back on and watched it refill. It didn’t stop filling when it reached the “overflow” point on the flush valve and started running down the middle tube and into the bowl. (At this point apologies for any non-technical language – I am just an amateur.) I lifted the arm that raises the polystyrene float and the centre of the filler valve expecting the water to stop filling the cistern but it didn’t. So I’m thinking the problem is with the filler valve? If so is this something an amateur could tackle, or is it time to get a man in? I should add that the toilet is boxed in behind tiles, and it was a real struggle to get the flush valve out, I don’t know how the heck you get to the filler valve! It would need a plumber with small hands and a lot of patience. Also the cistern is quite low down in the boxing so you need to lean in and down to reach in through the hatch. The filler valve is well hidden to the left of the flush valve, against the left wall of the cistern. I can obviously see where the water supply connects to it but after that ….

Any advice/good or bad news would be appreciated. Thanks.

 

[Riley]

Just to be clear is the filler bottom entry or side entry

 

[oz-plumber]

Sounds like the fill valve is knackered.

There should be an isolation valve accessible from inside the cistern.
Turn this off and disconnect the fill valve.

Not sure of the setup with your particular cistern, but you may have to remove other components to remove the fill valve.

You are correct saying the job requires patience. Some of those concealed cisterns require valium or equivalent prior to doing repairs.

 

[Riley]

Ha ha

 

[Jaycee]

Just to be clear is the filler bottom entry or side entry

Hi Riley. Thanks for the reply. It is side entry.

 

[Jaycee]

Sounds like the fill valve is knackered.

There should be an isolation valve accessible from inside the cistern.
Turn this off and disconnect the fill valve.

Hi oz-plumber, thanks for the reply. The isolation valve is (just about) accessible if you twist your head off to see it! I managed to turn off the water to take out the flush valve to check the seal, and it is off at the moment. I just need to pluck up the courage to try and remove the filler valve. Think I will do a lot of googling/looking at diagrams before I attempt it. And get some valium in!

 

[Riley]

As mentioned above. Yes should be doable probably with a little blue language

 

[Jaycee]

As mentioned above. Yes should be doable probably with a little blue language

I'll try and keep it ladylike!

 

[oz-plumber]

Hi oz-plumber, thanks for the reply. The isolation valve is (just about) accessible if you twist your head off to see it! I managed to turn off the water to take out the flush valve to check the seal, and it is off at the moment. I just need to pluck up the courage to try and remove the filler valve. Think I will do a lot of googling/looking at diagrams before I attempt it. And get some valium in!

 

[Jaycee]

Should there be a message here oz-plumber?

 

[Jaycee]

I'll try and keep it ladylike!

Hello chaps (and any other chapesses on here), thought I’d let you know that I today fitted the replacement fill valve on my Grohe loo, after waiting rather longer than the “4-5 working days” for it to arrive. After inspecting the old fill valve in the meantime, I think it may have had a problem with the inlet valve red/clear membrane. But if the other one goes wrong I will know where to look first. So feeling pleased that I didn’t have to pay someone to take down/replace the tiled boxing, remove the cupboard from above the toilet and take out/replace the fill valve!