Elderly cat breathing difficulties when purring

[MamaCoop]

I have one similar to the picture here and can not make it work properly. Anyone got the hidden touch/nack of how to get it to work/the right order to make it work?

It's level. 

When I fill it up I move the niblet down to close the hole. 

When filled I close the top to create a vacuum

Then move the niblet up to expose the hole and the water fills the bowl. 

However it never refills the water when drunk. 

To refill I have to undo the top to release the vacuum and then tighten again when the bowl has filled with water. 

It doesn't refill itself. 

What am I doing wrong? 🤔🤔

[MamaCoop]

has anyone got one of these and has any advice? 

[Beantree]

It should refill when the water level in the bowl drops below the hole in the feed pipe. The only reason I can think of is that the hole is blocked to some degree. That could simply be because there is some 'flash', a thin section of plastic in the hole, left from the manufacturing process? Needs to be emptied and studied with a magnifying glass.

[Cat tails]

@Beantree Exactly what I was typing just now too.