Questions about a flapper valve...

[Masood]

Hi all,

Replaced a couple of toilets last week, and I'm curious about the flapper valves.

What does the rubber tube do? I don't think it's a vacuum tube, as there doesn't seem to be a sealed chamber. And what is the adjuster for (the little black knob)?

Thanks in advance - it bugs me not to know how things work!

 

[PlumbersMate]

The tube is a drinking straw

 

[Keefy]

Not sure but my first thought is that it might somehow help by preventing the flap becoming pressure sealed - much like a chest freezer lid.

 

[rocketmanbkk]

I think Keefy may be right. I also thinks its something to do with removing the air and keeping the pressure?

 

[REDSAW]

long and short flush. the tube sends air down to break the water pressure seal?