I have a Pentair Clean & Clear cartridge filter and I recently replaced the cartridges. Ever since then, whenever the timer turns off the pump, built-up air pressure in the cannister forcefully blows out through the suction side plumbing and out through the skimmer. This empties the plumbing completely and breaks the syphon. I know someone out there knows why this happened, but that someone ain’t me. DS
Hello Rocky5150 - Did you try bleeding the air from the filter when the pump started? Does that make a difference?
More than likely you have a suction side air leak. The common areas include the pump lid o-ring, the fitting going into the pump intake or the valves in front of the pump.
Pool technicians are creative at finding an air leaks. One of these cool tricks is using incense. Light a few sticks of incense and hold the stream of smoke close to the suspected areas; if an air leak is present, the smoke will be seen getting sucked into the leak. Another method is using your garden hose to source the pool air leak. While your pump is circulating, run a steady stream of water over the suspected area and its seams; if the area is pulling air when water is applied to the leak it will block air from entering the system. When the leak is blocked by the water the pump should prime in a few seconds as long as there are no further leaks.
InyoRob,
To clarify, if I bleed off all the air in the filter cannister until water comes out and then come back an hour later and do it again, there will be high air pressure built up in the can. If I were to just turn off the pump like normal, all that air then blows back out through the suction side in the opposite direction of the normal water flow. If I purge the air first and then shut down the pump, it can go all night and all day before restarting it and it will hold prime. Would not a leak on the suction side cause it to lose prime while the pump is not running?
I want to be sure I’m understanding you correctly. In your initial statement you said the pump shuts off and the plumbing is emptied. In the last statement you said it can hold a prime over night. I am at a loss as to how this could happen. I have not seen plumbing lines empty and then refill without the pump running (unless the pump is below the water level).
To answer your last question, you can have a suction side air leak but not fully lose prime.
InyoRob,
*Here is what I said about keeping prime:"*If I purge the air first and then shut down the pump, it can go all night and all day before restarting it and it will hold prime." The only time the unwanted blow-back happens is when the pump shuts off either by itself (it’s on a timer) or if I turn it off without purging the air first. This has forced me to not leave the pump on the timer and has forced me to turn it off manually every time. To complicate things, the plumbing is buried beneath my deck, making it hard to access to test for leaks. Thanks for your help. I think I may have an expensive problem on my hands. However, I do have an off line chlorine feeder that may be sucking air. I will check the O-rings as well. When I changed the cartridges, I had to replace the band and I put silicone lube on the O-ring when I closed it up. I didn’t change the O-ring though cuz it looked OK. Thanks! DS
You may want to consider adding a check valve before the pump on the suction side. This would prevent that unwanted blowback.
Let us know how everything turns out. Good Luck!
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Will be contacting my pool service guy to install that check valve. Thanks for your help!
Hello, Rocky5150,
This sounds like a great choice. Hopefully while they are there, they can check to see if there is anything additional going on with any air leaks in your system. Always remember that pool plumbing is a closed system and should not get air in it on a regular basis unless you open a lid. Once that air has been purged, it should remain purged.
Good luck and please update us on how things turned out!
Alan