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