[C320-list] The funtions on the head

[Rick Evans]

This may be a strange question but the stickers on my marine head wore off and I'm unsure which way to pump etc. 

A Careful Wish is a 2000 model sail number 724.  

I am unsure of the head model so please bare with ny ignirance. If I leave the switch to the left (pointing towards the bow) and pump the head seems to suck down the waste and fill with water. So what is switching the button to the right (towards the stern of the boat) do. 

Any help would be appreciated thanks rick
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