Pump pumping air on start-up

[tnthudson]

I'm a member here, but my buddy isn't...he has an inground pool with a Hayward "Super-Pump"(?) and I know he has a sand filter...
anyway, he's just opening his pool this season and he says the pump is pumping air into the pool, so that it creates bubbles/foam. He's had it happen before, but took the top off the pump and made sure his gasket was okay, and the problem stopped on that occasion.
This time, however, he checked his gasket and even applied some Vaseline (I think?) to it to be sure it sealed, but the pump is still putting air into his pool. He can't tell where air could be getting into the system anywhere else. He's had the pool forever, so it shouldn't be a 'noobie' mistake.
Any ideas? thanks

 

[JohnT]

Pump drain plug O-rings? Water level in the skimmer or sticking skimmer weir? Clog in the skimmer piping? Anything new in the system?

 

[spishex]

No vaseline on the gaskets, please.

You should also check the pump inlet (male adapter threads) and any fittings on the suction side plumbing, especially unions and valve stems.

 

[reebok]

paragraph 3 has a test that helped me out with a similar problem.
pool-school/leak_detection

 

[tnthudson]

Thanks, that's exactly what he did...it's a bad valve on his skimmer line. He's handy enough to work with plumbing (unlike me), so he thinks he's got it licked.