Air bubbles out the returns after every backwash, chasing this down

Started by plumberdave · · 1 reply
Back to the forum
Reply
#1
Look, this one's got me scratching my head a little. Every time I backwash the sand filter and switch back to filter, I get a good minute or two of air bubbles spitting out of both returns before it clears up. Pump primes fine, no air in the pot, pressure's normal once it settles. Checked the multiport o-ring and the lid o-ring on the pump basket, both look fine, lubed them anyway. My gut says it's drawing air somewhere between the valve and the pump when the flow direction changes but I can't find a weeping fitting anywhere on the pad. Anybody else chase this down before it turned into a real suction leak. 1.5 inch schedule 40 pad, nothing fancy, just trying to catch it before it gets worse.

1 Reply

#2
Funny you mention the minute or two, mine does almost the exact same thing but only lasts maybe 20-30 seconds and I never thought much of it, just figured it was air trapped in the backwash hose line itself working its way out through the multiport before it fully seats back to filter. Never chased it further than that since pressure's always been normal for me once it clears, so not much help, just wanted to say I don't think it's automatically a sign of a leak starting.