Hi, I bought a new home with pool 5 years ago and things worked fine...until February. That's when I noticed that my spa was slowly draining into the pool when the pump was off. I soon traced the problem to the Pentair spa return check valve where the flap seal had deteriorated. I replaced the flap assembly with a new one from Pentair, but the problem only slowed down. I noticed that when the pump was off and the return valve was split 50/50 between pool and spa, the flap would pulsate, making a clicking sound like an windup watch. Over night the spa level would go down about a foot. If I shut off the spa return using the 3 way next to the returns, the pulsing, clicking and draining stops. The pool store that sold me the replacement flap exchanged the the old one for a new flap. The visible oscillation seemed to stop, but the clicking continued, as did the draining. If I move the 3 way next to the return lines to shut off all the flow from the pump/filter assembly, I still have the same problem, but to a lesser extent.
Two pool service people have looked at it and are stumped although one suggested that the check valve was way to close to the 90 degree coupling setting of some sort of cavitation. The other suggested a stronger check valve. Since the system worked fine for 5 years until the flap seal failed, I can't understand why a plumbing configuration would suddenly cause a problem.
I did keep the pump off for a full day and the spa did drain down to the level of the returns. To me, it all points to the check valve, but I can't figure out why two model specific replacement parts, didn't fix the problem. Can someone please help?
Two pool service people have looked at it and are stumped although one suggested that the check valve was way to close to the 90 degree coupling setting of some sort of cavitation. The other suggested a stronger check valve. Since the system worked fine for 5 years until the flap seal failed, I can't understand why a plumbing configuration would suddenly cause a problem.
I did keep the pump off for a full day and the spa did drain down to the level of the returns. To me, it all points to the check valve, but I can't figure out why two model specific replacement parts, didn't fix the problem. Can someone please help?