Air in Lines

[VickieC24]

This morning when I turned on my inground pool there was a large amount of air belching into the pool from the return lines. I also had to bleed air from the filter. Once I let it run for a minute everything looked fine. No air bubbles anywhere that I can see now. I turned it off again for about an hour and turned it on, no air this time. Right now it's running. I'm not sure if it's lost water or not. I've marked the level.

This is the first time I've seen this. The pool was totally overhauled about 4 years ago and have not seen any air since that time. (All lines and fittings replaced, new skimmers, new pump, new liner, new masonry surrounding the pool...the works.)

Right now, as it's running:

Pump basket has no air bubbles and had not lost its prime.

No air bubbles at all from return lines

No drips.


I plan to plug up the skimmers and returns but can't do that until tomorrow night.

In the meantime, what sort of leak would allow air into the system while off but then show no air bubbles once running?

(I'm hoping I don't have to have the new concrete dug up already.)

Thank you-
Vickie

18x36 inground vinyl-lined
Hayward DE4800 filter
1 1/2 HP Hayward Super Pump
Raypak MV Heater

[Vinyl_Guy]

In the meantime, what sort of leak would allow air into the system while off but then show no air bubbles once running?



Well it's most likely not a suction line, so digging up your deck probably isn't in your future. Air being entered into the system via a suction line would occur during filtering. Yours clears up right away. If there was a problem with a suction line, you'd get intermittent bubbles in your pump, then out the returns.

Sounds to me, somehow some air got into your filter, piping, pump or all three via the "topside". The water wants to drain down back into the pool, unless your entire system is below the level of the water in the pool. Think of liquid in a straw with your finger on top of it. Once there's even a tiny leak of air the water "drops", leaving air in its place.

You might have a gasket somewhere that's getting a little old or dray and is not quite sealed. It might not show as a leak as the pump runs but only as air in the system when it sits for long periods of time.

When a system loses "prime" during periods of idleness, but yet doesn't show any "drips". It's a sign that the "leak" allowing the water to drain lower and leave a pocket of air is on the suction side. Since when the pool is running it's not forcing the water "out" the same leak. Pump lid? Winterization plugs? If it's forward of the point of suction (front of pump where lines go in) , it would most likely pull air, in the form of intermittent bubbles.

I'd "batten" down all the hatches by tighten things. Tighten them by hand and don't force them, most pool equipment is meant to be "hand tightened". Once they seem tight by hand that's really as far as you should go. If you feel you don't have adequate strength you can use a tool of some type (Chanel Locks or pliers), but do it very gingerly and with care.

So go through every thing "topside". The pump lid (window) thumbscrews, even check the winterization "plugs" in the body of the pump. The bleeder on the top of the filter, and even the two unions connecting the multi-port, don't forget the drain plug too (but that would show moisture) . Any "union" or other fitting not glued can be addressed by just checking to see if it's tight or not, any of them could be a suspect. Give em all a good "twist" you might find one that has loosened because of the "jerking" of the pump when it goes on and off, or because a gasket has become older, drier , and thus smaller.

Even something as simple as not seating the multi-port selector just right can cause air to infiltrate from the backwash line. Did you backwash and re-earth the filter previously to this problem? Perhaps the very night before? Did you dissemble the filter and clean the "grids" recently? Perhaps the seal between the two filter body halves isn't perfect.

I wouldn't be too concerned, even if it is a "leak" it's most likely topside by the very fact the system re-primes itself on its own. It's most likely something that can be addressed with a "part" or gasket.

The difficulty with trouble shooting this type of problem is: the problem doesn't last long. By the time you go to do anything or reproduce it, it's gone. Not a bad "problem" to have, one that goes away ;).

Good Luck.

[VickieC24]

Thank you for your reply.

Yesterday morning I checked the water level before turning it on and it hadn't lost any water. No air at all in the pump basket. When I turned it on it was fine, no air anywhere. Fine today, too.

There had been no backwashing the day before or any turning of the multi-valve. The only thing I can think of is that the bleeder at the top of the filter may have not been tightly closed. I would have thought I'd have seen water squirting out there, but it looks like only the filter was involved. When I saw the air I bled and tightened that valve so maybe that was it.

Still a mystery...

Vickie

[Vinyl_Guy]

Yeah I don't think it's a major problem at all. Just an odd leak that manifested itself in a system wide short burp.

I'd still give everything the old hand tightened test just as a precaution.