Type of vent for up and over pipework from pump

HI Folks,

Novice question here. I just received my salamander pump and because the pipe run from the pump goes back into the attic and down to the shower they recommend "air vents" on both the hot and cold pipe run.

What I can't work out is if its a vent to get air out, or leave air in. I can come up with some pseudo logic for both.

a) vent to let air in. (similar to vents on waste outlets)
because of the fall from the highest point toward the shower when the pump switches off the water in the pipe may be pulled towards the shower and there will be a small vacuum just above the pump which would interfere with the pump for next switch on. (Not likely)

b) vent to let air out.
When the pump switches off "bubbles" will travel to the highest point and there will be a small airlock/bubble at the highest point. Possibly true but I would have expected that the pump would blast that through when it turns back on.

The salamander help line is shut at weekend
I assume that in both cases its a device that is put inline with the pipe run. What version should I get to limit impact on flow from pump.

Thanks,

You can buy aav's(auto air vent) these allow air to be expelled automaticaly but will not allow air to be drawn in. Probably about 7 or 8 quid each.

Thanks for that,
So you think that the vent required is to solve option b). Air buildup in the highest point.

If that is the case then aavs sound like the way forward.

The job is to vent air out of the pipework.
Air in the pipes can cause the pump to run when another tap elsewhere is turned on or off.

The air behaves like a spring, and the movement of the water in the pipes induced by opening another tap can trigger the pump flow switches.