Pump loses prime and getting worse now

[kittersue]

All my pool equipment is about 4 feet above the water level. The last few summers there has been a minor issue with air entering somewhere, because I would get bubbles from the return jets whenever the system started up for the day. Last summer, it was much worse, I would get 3-4 HUGE bubbles that broke the surface of the water when the system started. Any time I cleaned the pump basket and introduced air when taking off the lid, it meant that it lost prime for a few minutes. Aggravating, but not bad enough for me to want to get the pool company out to check. We just started up the system for this year and this morning I happened to be out there when the pump came on and heard it struggling to prime and the basket had no water. I waited almost 10 minutes. I remembered that the pool company said that upon initial start up it can help to close the skimmer returns and only pull from the main drain. I turned off the system, closed the skimmer drains, and it still would not prime. Turned off the system again, opened up the skimmer lines, and was going to open the pump lid and manually put some water in the pump basket to help, and when I opened the pump lid the basket was full of water (not sure how that happened). I quickly put the lid back on. Turned the system on, the basket drained, but then within a few minutes the pump primed and the system worked normally. My pool water level is fine so there's no leak. I do have a few minor drips in my system--the DE filter has a steady drip from the drain plug--and has been that way for a while. I've already checked the o ring, lubed it up, put plumbers tape on the threads, and all that helped slow it down. I do have a drip from a pipe near the site glass when I backwash but that also has been there for a long time. When I turn the system off, and put my ear against the DE filter, I can hear a "glub, glub, glub" like water makes when it's draining out. When I put my ear on the Multi-port valve, in all positions, I hear a soft gurgling/hissing noise. My pump was newly installed last year and never has air bubbles in the pump basket so I feel like it's not a suction issue. So what happens when the system is off? Is water leaving my pump and my filter both? What could be letting in so much air that the system is basically draining? Also, I hope the photo is ok, I basically have two skimmer lines, a main drain line, a Whisperflo single speed pump, a Pentair DE filter, an inline chlorinator we never use, and the Pentair gas heater. No water features or automatic vacuum. We have a slide that has a valve by it to let water flow but that's it.

 

[mknauss]

So what happens when the system is off? Is water leaving my pump and my filter both? What could be letting in so much air that the system is basically draining?

Sounds like the system is draining when the pump turns off. Those 'minor' leaks let air in. Fix them.

 

[Pool_Medic]

Are you certain the filter body ring is seated properly and tightened enough?

 

[kittersue]

We always lube the big filter O ring and tighten the spring to the same place each year (we measure how many threads still show). I turned off the system this afternoon and closed the skimmer and main drain valves just as a stop-gap measure to keep water from draining out of the pump. The gurgling in the filter stopped, and the pump still has water. However, I went out a few minutes ago and air is definitely being sucked in--I see bubbles in the sight glass that are heading into the Multi-port valve and I hear air in the filter. I tried putting some shave cream on some of the likely places--around the MPV handle base, around some of the pipe joints of the waste pipes, the connection to the MPV, and also put it around the air release structure on top of the filter. Nothing. At this point I am stumped and I guess the pool company is the next step.

 

[PoolStored]

We always lube the big filter O ring and tighten the spring to the same place each year (we measure how many threads still show).

Not sure that it will solve this problem, but may help with other problems in the future. Manual indicates that the o-ring should be clean upon installation. There are other notations for lubricating other rings, so I would not lubricate the ring. The manual for mine specifically states NO LUBE.

Second, the manual indicates that you should tighten the band until the spring coils are touching. From the manual:

First tighten the nut using a 7/8 in. wrench and then tap around the outside of filter clamp with a rubber mallet (or similar tool) multiple times around the entire clamp to fit the clamp properly. Continue to tighten only until the spring coils touch. Note: The clamp is installed correctly only when the spring coils remain touching after tapping the clamp (see Figure 3). If the clamp spring coils do not touch after tapping then continue to tighten the nut as instructed above in Step 8.

Page three here: https://www.pentair.com/content/dam...ilters/fns-/fnsplus_install_guide_english.pdf

It could be that if you follow the process in the manual, may help?

 

[kittersue]

Oh my gosh, I had no idea! The pool company left us a binder with basic instructions only. I took it upon myself to lube the O-ring because I know you need to lube other ones on the equipment. But that's my fault for not researching. I'm going to check the spring clamp shortly because I feel like there could still space between the coils (the sun is not up here, yet). It would be wonderful if a simple fix like that could solve most of my problem! Thank you so much for the suggestion and I will post back this evening!!!

 

[kittersue]

Lots of space between the spring coils... I just tightened them as much as I could, my husband will need to do the last few turns as I can't get the nut to move any more, but the space is almost gone between them. Fingers crossed!