Not necessarily. The mav 3 valve will when not activated, vent the output side of the valve into the box. Unfortunately I don't have the check valve part number handy. If you are using a mav 3 to actuate mav2's using actuators, you will eventually over-pressure your box and either hold the mav-2's on or blow up your box. Generally the latter. If you use a single mav 3 to fire a single cannon, it will vent when not firing the cannon, however it is not good practice and unnecessary.
um using a mav 3 to actuate two mav2 so if eneyone knows the check valve part # can you let me no. i dont need my box to blow up. ty steve
If you put a check valve on an MAV-3, the overall result will be the same as if you had used a MAV-2. The check valve will prevent the gas inside the MPA-3's from venting. While that does prevent your watertight box from getting blown up, it also prevents the MPA-3's from releasing the MAV's that they are attached to. You could just use an SMAV-3. That's the sub-miniature version, and its vent port is NOT through the button. It's actually on the bottom, so you won't overpressurise your watertight box The SMAV-3 doesn't flow quite as much air as the MAV valves do, but since you're only using it to trigger poppets instead of firing a cannon you should be fine. SMAV-3's are also commonly used as the firing valve in Big Gun cannons.
In that case, I just tried Clippard's website, www.clippard.com, and found the MCV-1, which appears to be what you want. Take a look at what they say about it.
Oh, so that's what. You use the check valve to depressurise the box, without letting any water in. Clever! I just had an interesting thought. If you put the check valve on the bottom of the box, then if the box leaked it would force the water out of the box before the overpressurised air. Just like a submarine ballast tank! Probably not practical, but interesting nonetheless.
