At what PSI should the one-way check valves open? I am trying to re-diagnose my check valves. I find that when I blow into the check valve (with a hose on it, so I can get a positive seal) with my lungs, I can not get much air to pass. The restriction is immense, and only a faint whistle can be heard. Is this normal for the check valves to only open at higher pressures (more than one's lung capacity)?

 

i don't have a number for you but check valves should open at almost zero pressure.

as an aside, i have also found check valves that passed the blow thru test yet leaked in service. if most other components check out it would be smart to use new one way valves.

aftermarket one way valves are inexpensive, immediately available and work well, albeit perhaps w a shorter life.

howard coleman

 

don't forget they install in opposite directions as one holds vacuum and one pressure.

howard coleman

 

Thanks for the tip. I suppose one of them is dead then, seeing as it doesn't blow air at all. Do you recall the valves making a whistling noise when air passes through it? Also, is there a difference in pressure ratings between the green/black and green/white valves?

 

WaLieN,

The check valves shouldn't "open" per say. They should stop air in one direction and let air through the other.

 

just to confuse matters, iirc at least one of the check valves is "restrictive" in that it does provide some resistance to the air blown through it. but not much.

-b

 

Check valves are not the same.

Some have a rated cracking pressure that requires a certain pressure before they'll open. This includes checkvalve with a bias spring.

Some have almost no cracking pressre and will open at almost no pressure.

Haven't opened one up yet but I doubt if most of the green/blk bodied check valve are the cracking pressure type.