We have one of kettles with the plunger in the top to pump out the hot water, similar to the one in the picture.

So it stopped working, that is no matter how furiously I pumped the plunger no water would come out. Took the lid apart and cleaned up the plastic diaphragm thing inside and all is well now.

Thing is, in the lid behind the stainless steel plate that holds the seal there is a steel ball that just rattles around loose and does not seem to do anything.

Anyone enlighten us as to the purpose of the steel ball?

Without seeing the lid assembly dismantled it's difficult to give a 100% answer, I have recently cleaned a similar hot water urn here, I don't recall a ball baring loose or otherwise inside. Has it always ratted? Can you compare with a similar device in the shops - waste of time asking the sales staff.

Might be part of a safety release for the builld up of stream pressure, but I doubt it as there is normally a thermal limiter on the heating element. Could be part of the pivoit/hinge although my one is purely plastic interlocking levers.

Maybe when you pump it closes the air intake, then on the release it lets air in.

sounds like a non return valve. Which allows you to push and pump.

Only guessing but I think it is a steam relief valve if the thermal device was to fail the kettle would be like a bomb with a build up of steam pressure

I will go with the steam relief valve as it has to have one. Without pressure ball will cover the escape hole but if steam builds up inside let it out just as a weight is used on the top of a pressure cooker to let steam escape when pressure gets too high.

Take it out and try it, then you will have your answer.

A simple form of Pressure relief valve. Like Offset said, if pressure was to build-up the urn would explode.

Given that the thing has stopped pumping, and there's a ball running around loose in the lid, I would definitely have to go with it being part of a non-return valve that has come adrift

Yes I thought at first it was a non-return valve but the way it's set up it would need a spring to keep it in place and there definitely is no spring.

Again the pressure relief valve crossed my mind but when the lid is closed the ball is not sitting on any sort of seal, in fact the holes in the inside of the lid that allow the pumped air in would let any steam bypass the the ball.

I would take the lid assembly apart again to take some photos but I noticed the plastic that holds the screws has gone a bit brittle so don't want to chance dismantling it again.

Anyway thanks for the replies guess it will stay a mystery for the time being.

Its to stop water being sucked up into the pump when you overfill the kettle i think.

Oh god I'm obsessed now. No, you have a pump lock which pushes the ball up to block the bellows.

No, when you open the lid the balls rolls down to block the hole and stop ants crawling in there.

No,...errr,,...

Edited October 19, 200916 yr by dogleg

Its to stop water being sucked up into the pump when you overfill the kettle i think.

Oh god I'm obsessed now. No, you have a pump lock which pushes the ball up to block the bellows.

No, when you open the lid the balls rolls down to block the hole and stop ants crawling in there.

No,...errr,,...

Just the type of valuable and interesting information I learn here on a regular basis.

Perhaps someone with a similar kettle can take a look and maybe post some photos.

It's only three screws to undo inside the lid

Just make sure you don't drop and loose the steel ball

I figure the factory workers add a marble/steel ball to a kettle each shift just to screw up the guarantee/customer satisfaction system. Our kettle does not rattle so guess no ball. But someone please enlighten us as my curiosity is aroused.

Someone has lost one of their marbles!