have a 30k gallon inground pool with Hayward sand filter; location Phoenix, AZ. Within the last 3 weeks the pump will run about 15 lbs pressure, then back off to 10, then back to 15, ect...After the air enters the line, the pressure drops, until the air comes out the return in the pool bottom, then the cycle continues.
Air is clearly getting into the system somewhere; here is what has been done, to no avail.
-All ABOVE ground, intake plumbing,has been replaced up to the round filter with clear lid
-The round filter, clear lid and o-ring have been replaced, this bolts directly to the pump. O-ring was lubed.
-the "2 way valve" controlling suction from vacuum and/or skimmer basket replaced
-new 3/4 hp motor, (same hp as old)
-new vacuum hose, (old hose segments were cracked)
When turning the intake valve to 100% skimmer basket suction, (removing suction from the vacuum) the pump still looses pressure, so I'm guessing this is where the problem lies; not the vacuum intake.
Short of ripping up all underground intake lines, does anyone have suggestions? I REALLY want to get this thing back to pumping 30 lbs pressure like it was last summer.