Ballcock noob

Hi All,
I am not a plumber by trade but had a ballcock valve in my water tank disintegrate on me over the weekend and caused a small torrent of water to descend down from my loft!
Anyway, I resolved the problem by purchasing a new ballcock and replaced it.

However, the design of the valve got me thinking.
As the water fills the valve gradually shuts off the water supply until it eventually stops. this seems to be a simple enough design but the drawback is that as it approaches the end the amount of time to stop the flow is very long particularly if the tank is large in surface area.

My question is, does a valve exist that allows the water to flow at full rate until the desired level is reached when the water is then shut off completely?

Sort of like a digital switch instead of an analogue one?

Anyone?

Mac.

If yours has a float on a rod, a better choice might have been a Fluidmaster 400 or a Korky Quietfill. Both of those fill at near full volume and then shut off. They are likely less expensive than what you installed and are easily repaired.

I prefer the Korky (formerly Hunter) because the water fills to the slot in the side of the float chamber and quickly raises the float. In hard water areas, the Fluidmaster can get gummed up with lime and not slide well. The Korky has fewer moving parts. Gerber has their own "pilot valve" that works similarly to the Fluidmaster.

I also like the Korky QuietFill over the Fluidmaster, they fill fast, and they don't hammer like some of the others.

If you shuts off like a digital watch, it would be one loud bang! from the pipes.

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Originally Posted by machasm

Hi All,
I am not a plumber by trade but had a ballcock valve in my water tank disintegrate on me over the weekend and caused a small torrent of water to descend down from my loft!
Mac.

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I thought the overflow tube was supposed to prevent that?

Quote:

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I thought the overflow tube was supposed to prevent that?

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That would be the idea, but if the fill valve is spraying, it can spray past the lid and down the side.

A little bit of info here about flappers:

The overflow on toilets is a tube that exits just alongside the flapper. Some flappers, as they get older, swell a bit and sink down into the seat, plugging the overflow. An old flapper can cause a serious flood if the fill valve doesn't shut off.

Ordinarily, the overflow tube will take the excess water from a fill valve that doesn't shut off. In addition, the overflow tube MUST be cut off below the lever handle hole. Sometimes, a replacement overflow tube is too high.

Quote:

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Originally Posted by mikept

I thought the overflow tube was supposed to prevent that?

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the other day I went to a job were a ballcock didn't shut off and flooded. the overflow tube had been replaced, and was higher than the trip lever hole. the flood all came from the trip lever hole.

Machasm, You wouldn't happen to be in the UK would you? Talking about the ballcock for your cistern up in the loft would ya?

Hi Guys,
Thanks for the replies.
Yes I do live in the UK.
Terry was closest to the reason for the spillage.

The ballcock was of the type that the water, when filling, was directed upward into a plastic U bend which then redirects the water downward into the tank.
Unfortunately this plastic redirector literally blew off the end of the valve.
The tank did not have a lid so the water was projected directly skyward hitting the felt lining in the loft (attic for you yanks) and began to 'rain' everywhere.

I am scrambling around at 7:30 a.m on a Sunday morning completely naked getting soaked trying to find the isolation valve!
Not a pretty sight I can tell you.

Back on topic, I was thinking of something like a ballcock lever but instead of gradually decreasing the flow rate by closing a valve over the same period instead have a rocker switch which is either in the open position or closed position and nowhere in between.
I understand that there would be quite a bang when the flow is turned off and on but the design could be perfected to open and close say over a 1 - 2 second period instead of an 'instant' off.

BTW if this thing isn't invented yet you heard it here first!

Mac.

Your thinking of a spring loaded switch which fires very quickly into an off position once a certain pressure from the float is attained. I think that is kind of unnecessary because the better designs go from completely on to off within a smaller rise in the water float height.

ALL the "floatless" valves close rapidly. It is the action of the float ball having to rise with the water level, combined with the slower input of water increasing the time to raise the water which causes that last long shutoff period. If the valve does not shut off, or reduce its flow when it fails, the overflow tube will not be able to accept the full flow and the tank WILL overflow, regardless of whether the refill tube is intact or not.