Air Bubbles

[tcat]

OK, I've tried "everything". Air Bubbles in the pump basket (at least a 3 inch bubble of air at top of dome), bubbles look like they're coming from the o-ring (but no cream gets sucked in), tiny air bubbles out of every jet. I removed basket dome clamp and just primed with lid only (easy to run shaving cream around edge), no change. No vortex in skimmer. Tried the shaving cream trick on every suction joint, around the o-ring, every screw fitting, drain valve... nothing gets sucked in (except air from somewhere I'm not seeing. Air with or without cleaner running. All I can think is crack underground, but I would think I'd start seeing mud. Pump basket loses 50% each night, takes about a minute to prime, but does prime. Equipment is above water level.

Any other tricks to find a suction leak?

There shouldn't be anything connected to suction except the one 2" drain line and one 2" skimmer line, right?

 

[Bama Rambler]

Have you checked the drain plugs?

 

[tcat]

Yes, removed, silicone grease, shaving cream all over the joint after....

edit: just went out to hose off the shaving cream... used slow stream and ran water over everything. I hear the pump make a new noise (like straw slurping), when I ran the water over the short piece of pipe into the pump basket (drain and skimmer T into this pipe). Air bubbles seem to slow. So I covered the pipe and fittings with shaving cream, and only a small quarter sized pocket of air remains. Shaving cream does appear to be getting sucked in, but looks like it sealed something... The pipe is 2" gray with a thread, maybe there's a small crack in it... next project, dry it all off and either coat it with something, or take it all apart.... kind of off the pump makes that noise it sealed...

 

[tcat]

Still getting bubbles. Can you have too strong a pump? I'm thinking maybe air is getting sucked under the o-ring. I notice bubbles go a way when I backwash/drain, but come right back when I go back to filter. Have two 2" lines (skimmer and drain), tee'd into 2" line into filter basket. Bubbled going away on backwash makes no sense to me. Pressure at DE filter is "20" (goes to 25 when dirty).

Pump is 5 years old. Any advantages of a 2 speed pump (have no spa)? I'm guessing a slower speed would eliminate the bubbles.

 

[Bama Rambler]

You have an air leak somewhere. It's just one of those hard to find ones.

A 2-speed might help the bubbles if it's only leaking under high suction. I'd just replace the motor on that pump with a 2-speed model.

 

[mas985]

I'm guessing a slower speed would eliminate the bubbles.

Not always. For many POs, low speed actually increases the air bubble in the pump lid. There are several theories as to why but from my own experience, I have seen out gassing bubbles form on the pump basket that tend to accumulate in the lid because there is not enough flow rate for them to get pushed out the return. Also, as BR points out, some lid designs seem to work better under higher suction than others so I wouldn't count on low speed working better.

But I wouldn't get too worked up over a 3" bubble either. That size doesn't hurt anything. In fact, a pump can run just fine as long as the inlet is complete flooded which means the water level in the pump would have to drop several inches before it becomes a big issue.

But on the flip side, if the filter is accumulating air and not purging itself, that can be a big problem. You can usually detect this by a large back flow when the pump shuts off as the compressed air is released. Some have even reported their skimmer lids popping off because of this. Then the leak should definitely get fixed.

 

[tcat]

I gets all kinds of "swealing" sounds when the pump shuts off. Mostly coming from the Multi-Valve area. I'm not worried about a bubble in the basket, more so about the basket draining nightly and having to reprime each morning. Primes easily, tales about a minute (or less). Looks like a new 2 speed is $700-$800... I doubt I'd save "that" much EE in 10 years... I'll wait until the pump dies.

edit: I also notice there are no bubbles (or much fewer) without the aux. cleaner pump running.

 

[tcat]

First time I've looked at the pool at night with the light on in a while. Looks like bubble problem isn't improving with or without cleaner off; with or without a well sealed basket lid; with or without shaving cream... could there be an internal seal in the pump causing the bubbles?

I do notice a pulsating action from the jets. Squirt of fine bubbles, then clear, then bubbles... alternates about every 2 seconds. I assume that's from some air getting into the basket, going from 90% to 95% to 90% prime? Could the pump be too strong? When I turn everything off, I get a bubble "burp" looking like it's from the lid o-ring (but hard to tell), about every 30 seconds. Takes about 4 hours for the basket to drain about halfway down.

Top of basket looks flat with a flat plate on it. O-ring is new, clean and well lubed (really can't believe it wouldn't seal under suction). I may just buy a 2 speed pump to start "fresh"... since I got the 5 year old single speed "free" with the house... hey, the 5 year old pool was "free" too... as was the 50 year old oak tree that I didn't realize dropped leaves in the spring until last week

 

[gtemkin]

Shaving cream does appear to be getting sucked in, but looks like it sealed something... The pipe is 2" gray with a thread, maybe there's a small crack in it... next project, dry it all off and either coat it with something, or take it all apart.... kind of off the pump makes that noise it sealed...

You made a good observation in which you may have isolated the area of the leak, but your next post didn't say you did anything to investigate it. Did you perform any actions to look for a crack - disassembly/inspection/etc - or possibly use thread sealant if it's a threaded connection?

 

[tcat]

I had "coated" that pipe with silicone sealant and was still getting air. But I tried running water over it again this morning at a slower rate, and bubbles did seem to be getting fewer. I tried the shaving cream again a section at a time, and think I have it nailed down (it is the gray pipe!). No bubbles from the jets at all and just one 1-2" one at the cap. The pump sounds real different with a sealed system. Looks like a pain to replace that 6" piece of 2" pipe (threads at both ends). Pretty much disconnect everything and rotate the whole pump....

I wasn't too concerned about it before, but has been getting worse. Thanks so much for the suggestions.

 

[gtemkin]

Looks like a pain to replace that 6" piece of 2" pipe (threads at both ends). Pretty much disconnect everything and rotate the whole pump....

It's very standard to install a union at this location so you don't have to "spin the pump" to disconnect it. "Spinning the pump" to unthread it inherently put you at much greater risk of creating a new crack especially if the pipe is aged in any way. I'd suggest a trip to the hardware store and for about $50-$75, you could get a union, some pipe, a few other fittings, some PVC cement and primer and replace much of that section. Otherwise you could call a service, but either way it will be a heck of a lot cheaper than buying a new pump.

By the way, standard Schedule 40 white pipe would be just fine. The gray pipe is heavier duty but really unnecessary.

 

[tcat]

I'm an idiot... you mentioned union, so I went to look to see what I needed... and sure enough, there is a union. For some reason, setting threads at both ends of the gray pipe made me think I had to spin the pump... much easier to unscrew the union first! All I need a short piece of 2" pvc with thread at both ends. It looks like someone used a big pipe wrench on the great pipe, claw marks all over it (probably why it's cracked).

edit: All fixed! Went to HD and got what I needed, union, 2" pipe, threaded fitting, silicone grease. Then went to take apart area in question. Existing union looks good, gray pipe looks good... decided to clean all, lube union o-ring, and reassemble. Turned on and just as it hit prime (there's a quick pressure pulse in basket), some water squirted out the threaded pipe to the pump basket. So THAT's where the problem is. Took it apart, really cleaned those threads, added a bunch of teflon putty, reassembled... not leaks or bubbles! Back to HD for a refund!

By the way, the threaded pipe actually bottoms out in the basket just hand tightening, not sure if it's supposed to. Seems like there should be a gasket at the bottom.

 

[gtemkin]

All fixed!.........

........By the way, the threaded pipe actually bottoms out in the basket just hand tightening, not sure if it's supposed to. Seems like there should be a gasket at the bottom.

Great! I think the gray threaded pipe is really an electrical PVC conduit part, although it should work fine anyway. It shouldn't, however, bottom out. It just so happens I wrote a post about a related situation with my pump. The post is at:

http://www.troublefreepool.com/fine-point-about-threaded-pump-fitting-very-long-story-t55687.html

I suspect your pump has a slight protruding boss that a proper o-ring style fitting is supposed to seal against. The person who did the original install didn't use an "o-ring boss fitting" (made up that name) and instead used the gray threaded electrical conduit. From what I can see in all the pump specs, the pool industry doesn't clearly define the connection interface for pumps very well. Instead, the manufacturers seem to list their own recommended fittings, but they don't go into any detail as to whether their fitting is an o-ring boss style or just a plain tapered pipe thread. Anyway, hope it holds tight with the parts it has now. I suspect it will.

 

[tcat]

All I can say is WOW... first time since I bought the house/pool (10 months) that the pump basket stayed full of water overnight! If it happens again, I know where to look, and will buy a gasket so when the pipe bottoms out it has something to seal against, it's got to be more reliable than plumbers putty.