A Perfect Storm in the Cistern

[Lonsdale73]

Any plumbers in the pplace able to offer some advice please.

Yesterday, the toilet cistern was taking forever to fill up and once it did it kept on filling so I removed the cistern lid and found there was water sprayig out in all directions but not very much of it. I tried adjusting the nylon nut which shot off into the cistern. I put it back together and found there was now a jet of water coming out of a nozzle and the cistern filled up pretty quickly. But now the jet won't shut off so there's a constant trickle of water from cistern into bowl.

To compound matters, there's a grey theaded part that looks like it's meant to sit inside a collar so that when the flush buttons are pressed, arms linked to the colla are raised and the toilet flushes. Except it won't stay inside the collar long enough for me to reassemble everything to test it. Anyone with any ideas or suggestions?

 

[CHJ]

Looks like your flow valve needs a new diaphragm washer.

similar to this but you need to check make of valve and design of washer as there are a few different patterns.

The flush mechanism is a case of adjusting the threaded (grey) item engagement to adjust the depth to match the lid and engagement of the push buttons when assembled

 

[Lonsdale73]

Looks like your flow valve needs a new diaphragm washer.

similar to this but you need to check make of valve and design of washer as there are a few different patterns.

The flush mechanism is a case of adjusting the threaded (grey) item engagement to adjust the depth to match the lid and engagement of the push buttons when assembled

I bought those very things this morning but they're solid; existing one has a central hole and a smaller one above to engage a locking pin. Do I just need to drill the holes myself?

 

[CHJ]

I bought those very things this morning but they're solid; existing one has a central hole and a smaller one above to engage a locking pin. Do I just need to drill the holes myself?

Sounds like you have bought the wrong pattern valve diaphragm, the way they work balancing the water pressure to close off the supply they are very specific to the design of the housing.

 

[AndyT]

I think you might need a Siamp diaphragm. If you do, buy several. In my experience they don't last long.

 

[Lonsdale73]

Thinking it might be simpler to replace both the intake and flush! Thanks chaps.

 

[Selwyn]

Get a whole new bottom entry fill valve. £15 max

 

[Sheffield Tony]

It's an ill thought out piece of plastic tut. Whoever came up with the idea of bottom entry cisterns needs their head examining too, the ceramic stuff is so variablein thickness it is hard to get a good seal at the best of times, so given the choice of putting the inlet above or below water line, the correct answer is obvious.

Give me a good old brass valve, top entry. Much more reliable.

 

[Lonsdale73]

Okay, played safe and replaced both the inlet valve and the flush valve. Still got water trickling ino the bowl!

Anyone know what size spanner is required for the locking nut that secures the flexible hose from the mains pipe? Largest I have is a 19mm and it won't go near it.

 

[Selwyn]

Could be blocked. Take the top off the new flush valve and run clean for a few seconds

 

[CHJ]

Okay, played safe and replaced both the inlet valve and the flush valve. Still got water trickling ino the bowl!

Assuming water level is not set too high on the inlet valve actuating float causing overflow (suspect most obvious reason):-

1. Flush valve is either not sealed correctly on the inside of the cistern.
2. or the flap vale is not seating flat within the flush assembly.
The latter is not likely on new product, usually cause by limescale or debris getting trapped under valve diaphragm.

The pipe connection I would expect to be 23-25mm across the flats dependant on brand.

 

[Lonsdale73]

Managed to remove the flush vlave, allowed water to flow though into the bowl, rinses the seal - which for a brand new item did have a bit of detritus on it already!), refitted and water was entering faster than before, now with added sound effects. Removed, rinsed and repeat. This time it reseated with an audible click, hiss has gone and returned to a slow trickle.

There's 110mm depth of water in the cistern so not even halfway up the overflow pipe. Screwfix have a video on youtube showing the inlet valve telescoping like a trombone but on mine the only think that looks like a catch release doesn't want to budge.

 

[Lonsdale73]

Thinking maybe the locknut that secures the flush valve to the cistern wasn't tight enough so water might have been seeping round the external seal outside the cistern, I picked up a dedicated flush valve locknut spanner this morning, stripped the whole lot down, adjusted the inlet valve so there's a sensible volume of water coming into the cistern and put it all back together again. Still got a continuous trickle entering the bowl long after it's been flushed. It's driving me nuts. Well, the boss is!

 

[sunnybob]

Maybe the problem is elsewhere. you say you had detritus immediately. that makes me think there is a problem elsewhere. a few months ago i had several taps start to leak. each one when removed and inspected had little black bits stopping the valves from seating.
I traced it back to the non return valve (check valve) by the main inlet. The black washer inside had disintegrated and spread through the entire house. Took me days to keep flushing all the crud through.

 

[AndyT]

Bob, that's interesting. I think you may have just diagnosed my problem. Having read this thread I was a bit taken aback to see that our downstairs loo was running continuously, although I had replaced the whole valve and flush mechanism quite recently. A video on the Fluidmaster website said the problem would be debris and sure enough there was a chunk of black rubber about 5mm square inside the valve. The loo is very close to the incoming main and the non-return valve had been getting noisy. What's inside one of those valves? Is it just a big rubber washer waiting to disintegrate?

 

[Lonsdale73]

Not sure if this is related or not. Had an intermittent issue with a dripping overflow; would drip for a short while, usually just after shower had been run, and would stop after a while. Now it's a constant drip. Climbed nto the loft to find an expansion tank I never knew I had with water dripping into it at a similar rate to water dripping out the overflow. The water in there is also warm (should it be?) and a good inch above what I believe is the outflow pipe. See photo

Boss has a recollection of the engineer who installed the new heating system saying the valve needed replacing but he didn't have one on him so he 'turned this one over'? I'm going to stick my neck out and say it's due for replacing. If, as I think, this is fed by the cold water tank, do I have to turn off the mains and empty the main tank before attempting to replace this ballcock?

 

[AndyT]

Bear in mind that I'm not a plumber but your installation sounds exactly like ours. That expansion tank should have a cold water inlet through a ball valve, from the mains, not the cold tank (which would be on the same level). With luck, there will be a stop tap in that mains feed, nearby. If not, turning off the mains stop tap will do.

There's also a vent pipe from your unpressurised hot water tank which will come up vertically, turn over and drain into the tank.
This is the source of the warm water, especially if the boiler is firing, the tank is hot and the radiators are off.

 

[AndyT]

"Turning over" probably means he took the little half inch solid washer from the valve and turned it over so the un-worn side pressed against the inlet jet.

You'll need a new washer this time!

And I should have said, the tank you describe is connected to the primary circuit, ie the water that circulates through the boiler and a coil inside the tank. It shouldn't be overflowing.

If you get overflow which stops and starts when the shower is used, that's probably from the big cold tank. When hot water is used, it's replaced with cold from the tank, which is then topped up by a similar arrangement of mains inlet, ballvalve and overflow.

 

[Lonsdale73]

Bear in mind that I'm not a plumber but your installation sounds exactly like ours. That expansion tank should have a cold water inlet through a ball valve, from the mains, not the cold tank (which would be on the same level). With luck, there will be a stop tap in that mains feed, nearby. If not, turning off the mains stop tap will do.

There's also a vent pipe from your unpressurised hot water tank which will come up vertically, turn over and drain into the tank.
This is the source of the warm water, especially if the boiler is firing, the tank is hot and the radiators are off.

I think you're right aboout the inlet off the mains so that's easy enough to isolate. The main tank has a slow drip too so going to replace both ballcocks and if there are still problems then I think I might just drown myself in one of the tanks.

 

[sunnybob]

Andy, its just a spring loaded plunger with a rubber (plastic) washer. When the water is flowing into the house it pushes past the washer. When the incoming flow stops, the spring pushes the washer against the seat and stops water flowing backwards into the mains (Its an anti pollution device).

My incoming has a 1" check valve, thats a lot of rubber to work its way through the system. When I took it out to check, there was literally no washer left inside it. I could see all the way through.

Our mains water is quite acidic but also heavy with soft scale because its all deep ground water from the tuffa rock that the island is made of.
That valve was only 4 years old. The one before lasted 8 years.