Watts air vents

Bernie Riddle_2

I noticed the 2 silver colored air (?) vents have 2 caps each. One is red, one is black. One vent is on the exp tank, one vent is on the end of a pipe coming out of the top of the boiler. Should these red and black caps be screwed on tight or loose?

Unknown

Andrew..............

Watts calls this a Duo- Vent, see if the attachment helps you at all.

Bernie Riddle_2

Thanks Dave!