Ballcock float collapsed

[seasickstevie]

A friend asked me to look at why his overflow was running.

A combination type copper cylinder and header tank. My first suspicion was the washer needed replacing, but it was more obvious than that - the float had collapsed.
I replaced it with a new one, and within little over a week the same thing happened with the new one.

Obviously the design of the cylinder & header tank divided be a thin piece of copper is a very poor design as inevitably the cold water in the header gets warm.

I thought maybe there are floats that withstand warm water, so went to a local plumbers merchant where there were three assistants behind the counter. Not one of them had ever heard of this happening before.

Someone suggested using an old-style copper float that will be resistant to warm water. A phone call was made to the plumbers merchant's supplier, but the reply was "not made anymore".

What's going on? The client sometimes doesn't use much hot water during the day, and as the immersion is on a timer (E7) the header water inevitably gets warm. Can't be the only person that this is happening to.

 

[seco services]

Poss it reaching boiling point and expansion is taking place causing hot water to enter the storage at the top.

It's not normal for the water on a combination cylinder to be hot/warm.

Check the immersion stat is working or set to 60c.

It's not a bad design they work well.

 

[seasickstevie]

Thanks. I'll check the stat tomorrow.

 

[Agile]

Took me all of one minute to find a copper float ! From £11.25 + vat.

But its not the problem as there is clearly an overheating problem.

Now to be sure is this a plain open circular cold water feed tank at the top of a cylinder?

Tony

 

[seasickstevie]

Yes, open circular cold feed copper tank fixed on top of hot water cylinder,all as one unit, and covered with foam. And a round steel lid on top of that.

Hadn't thought about the expansion pipe! I guess that must be tucked around the back. I didn't notice it.

 

[Agile]

Is it overflowing either now or sometimes?

These are usually just electrically heated but they are some heated by a gas boiler system. If the heating coil is leaking and the F&E higher then water will run into the cylinder and over flow from the top tank.

Similarly if a mains fed mixer tap is leaking cold mains into the hot!

Tony

 

[seasickstevie]

... usually just electrically heated but they are some heated by a gas boiler system.

Like I say - immersion on timer (E7) - Economy 7 (or whatever it's called these days). No gas boiler - no coil.

...if a mains fed mixer tap is leaking cold mains into the hot!

Interesting idea, but overflow didn't run when float replaced. Cold water running into hot cylinder wouldn't explain the float collapsing though. More likely the hot into the cold tank.