Sudden Drop in pressure. Help!

[ma3875]

Hi guys, Something really weird is going on.... I'm getting normal pressure, then sudden drop, then back up to normal, then back down and it stays there.

Things I've done:
Cleaned the skimmer line (only have one)
Blew out (with air) the skimmer line from the pump. no problems that I can tell.
Took off the motor at pump and checked for clogs, etc. Nothing...
Motor is about 5 years old and when taking it off the unit and operating in open air, works fine.

Any ideas?
Thanks

 

[JohnT]

Watch the water in your skimmer. Any surging or vortex?

 

[ma3875]

Nope just a slow crappy suction.

 

[ROB N]

It would be helpful to know what type of equipment you have. If you go into the user control panel and edit your signature to include your info, pool type, volume, equipment ect....

 

[ma3875]

Edited my signature! How's That?

 

[ROB N]

Excellent! Most helpful, Have you backwashed? Is your filter pressure high as compared to normal?

 

[ma3875]

ya I tried to backwash it however the pressure is too low to do anything...

I checked the skimmer line with a DRAIN KING. Water comes through no problem.

Also, it gets to normal operating PSI then drops.... builds up again... then drops...

really weird.

 

[Bama Rambler]

Is there air in the pump strainer basket when it's running? If so remove and clean the strainer basket o-ring and lube it good before putting it back. Check it for nicks or cuts while you have it out.

 

[ma3875]

Think I know what it is... stay tuned...

 

[waste]

This won't fix any problem but it will eliminate the filter - how does the pool run when you put the multiport on 'recirc'?

 

[amccarl]

I'm having this problem right now after having just replaced the pump motor. Investigating now, but if you did find an answer, I'd love to know.