Purpose of off-board Vent Plug?

[rich2202]

Originally Posted by Al Skierkiewicz

I would rather relieve the pressure and then disconnect the hose.

That would make sense if there were a way to relieve the pressure. The way the diagrams have it plumbed is the output of the two vent plugs are plumbed together trapping pressurized air between them.

I was thinking that the off-board vent plug would reduce the amount of air that would vent at the time of disconnection, but in the example, there is minimal air trapped behind the vent plug vs the tubing between the two vent plugs.

Now, if they required the off-board vent plug to vent to the atmosphere, and the off-board components are connected via a T connector, that would make sense. Close the on-board vent plug, open the off-board vent plug, and then safely disconnect the hosing. But, that is not what is described.