Bubbles in basket by pump, inlets in pool, no apparent water loss, no obvious leaks

[BallstonSpaKW]

In-ground 18x36 pool, 1 hp pump motor, heat-pump heater, Stenner chlorine pump, 1 skimmer and 1 main return, 3 pairs of inlets - 1 pair deep end, 1 pair shallow end, 1 pair on 4x8 shallow end steps. 4 cartridge 320 filter. 18 year old rotary gray and red-handled valves (5). The title pretty much describes the issue. Northeast pool ran fine all last year. Opening was fairly uneventful except motor bearings were shot. Pulled motor and impeller from pump assembly, swapped motor, re-atteched to impeller and reinstalled. The items I had to reconnect were drain plug on filter, cartridge assembly and cover, pressure gauge and inlet and outlet couplings to water heater. Also, the small coupling from the chlorine pump. I haven’t had to add any water all year, we have had only small amounts of rain. We do use a solar blanket to prevent evaporatio. I don’t see or feel any water leaking near any of the joints near the equipment. Liner is only a couple of years old and no obvious rips or tears, top edge is still over top of pool wall. No children - just occasional grandkids. If I get rid of most air by venting via pressure valve it “bubbles” up again in 5-10 minutes in the pump basket, which loses about 1 inch of water from the top. I run about 12 hours on and off throughput the 24 hour day, with the longest continuous stretch about 8 hours from 11:00 to 19:00. It seems to recover by itself, or at least it hasn’t yet lost more than that same inch of water.

Sorry to ramble, but wanted to provide everything I could think of.

What steps should I take to find this air leak, preferably easiest to hardest? Do I need to worry about it if I am not losing water?

Thanks. Kevin

 

[Richard320]

Easiest is to look for a vortex in the skimmer caused by low water or a sticking weir (flapper).

Then you get into pump lid gasket and drain plugs.

Beyond that it's valves and plumbing.

Suction Side Air Leaks - Trouble Free Pool is poorly formatted. It's two pages and the good stuff is on page two.

 

[BallstonSpaKW]

Ok - thanks for some tips. It wasn’t the weir or a vortex at the skimmer. But just wanting to solve the issue I worked on 4 other suction side items at the same time. Not great for figuringout which of them it was, but it looks like it was one of them. Re-reading richard320’s post led me to thinking that since it wasn’t leaking at the end of last year it must have been something else I put back together this year. I found the pump basket and motor plugs could be tightened ever so slightly more (maybe about 10-15 degrees), the pump basket cover had a few grains of sand around the gasket (which I rinsed and reseated), and the motor/impeller assembly gasket might not have been perfectly seated. Anyway, several hours later and I have not seen anymore bubbles.

Thanks for the list.

One last follow up - if I couldn’t have found the source of the air but I wasn’t losing any water, as long as the pump never ran way low is there really any problem with having air in the system?

Kevin

 

[Richard320]

Ok - thanks for some tips. It wasn’t the weir or a vortex at the skimmer. But just wanting to solve the issue I worked on 4 other suction side items at the same time. Not great for figuringout which of them it was, but it looks like it was one of them. Re-reading richard320’s post led me to thinking that since it wasn’t leaking at the end of last year it must have been something else I put back together this year. I found the pump basket and motor plugs could be tightened ever so slightly more (maybe about 10-15 degrees), the pump basket cover had a few grains of sand around the gasket (which I rinsed and reseated), and the motor/impeller assembly gasket might not have been perfectly seated. Anyway, several hours later and I have not seen anymore bubbles.

Thanks for the list.

One last follow up - if I couldn’t have found the source of the air but I wasn’t losing any water, as long as the pump never ran way low is there really any problem with having air in the system?

Kevin

You could end up with a huge air bubble in the filter under pressure. Then when the pump shuts off it expands and expels everything backwards through the pump back into the pool. And then the pump would have to reprime from empty every time.