Need some advice regarding Intermittent water loss and air in pump

[MiloD]

Hi all,
We have had the pool going on 8 seasons. This year we have been having 2 big issues, 1) air in the pump basket and 2) water loss has happened over night on 3 separate occasions ( 1.5-2 inches). I’ve tried several tests and can not figure it out. Not sure if there are 2 separate issues or if they are connected.
I’ve outlined below what I’ve tested: (the pump and filter O rings are supple and lubricated with silicone, all plugs are sealed with plumber tape, filters are new, all baskets are free of debris). We have floating weirs (old sylvan pool)

Any ideas of what to try next would be much appreciated , as would thoughts on the “diagnosis”.

Suction side Air Leak Tests:
1) Visual inspection of visible suction side plumbing:
Small hairline crack on superior surface of "pump joint connector ring" to the pool side plumping ( we have not touched this connection since instillation of the VS pump/cartridge filter in 2020, pool is professionally closed and we open it each year)
No water leaking around pool equipment
Pump seal is pliable and lubricated
Jandies are “ no lube” type
2) Smoke test (incense)pump at 3200rpm: Negative
3) Filter Pressure Tests pump at 3200rpm

	PSI	Bubbles	Loss of prime
Main drain only	8	Large	No
Spa drain only	13	No bubbles	No
Skimmers only (both)	14	Small	No
Main drain and skimmers	14	Small bubbles	No

At lower speeds there are more/ larger bubbles no loss of prime
4) “Main Drain Palpation/diver test” @ 3200rpm
Main drain on (spa drain and skimmer off), Very Large leaf used to cover the drains one at a time
4a) Right side open: pos suction (leaf stuck hard) filter pressure 5 psi
4b) Left side open: pos suction (leaf stuck hard) filter pressure 5 psi

Water Loss:
Bucket Tests:
1) In water with pump on with skimmers and main drain split 50/50-> no difference in levels (visual “measurement" only)
2) On side of deck with pump off (24hrs)-> No difference in water loss compared to pool (used calipers)

Below are the pump settings I’ve tested so far. The last time we lost a couple inches water overnight the main drain was off & main drain return and skimmers were on. The filter had air in it and I lost prime when I readjusted the values (waterline was at the bottom of the skimmers in the am, was 1/2 up the evening before)
I’m not sure how to set the main drain return and still get water back to the pump. I also am not sure if that would be needed.
I took the solar skimmer out of the pool so it didn’t get caught in a skimmer and mess up the test
Pump runs as follows:
2800prm for 12hrs starting at 7pm/1800prm for 4 hrs/ 1400prm for 4hrs)

Any advice would be appreciated.

 

[Texas Splash]

Welcome to TFP! Thank you for the detailed analysis provided. You've done some homework. I'll start the discuss with a few items. Others will follow I'm sure.

Small hairline crack on superior surface of "pump joint connector ring" to the pool side plumping

I'm assuming you are referring to the pump's outlet union nut correct? Pressure side as it goes to the filter next? If so, then being on the pressure side it would be a problem if you saw a leak (which you don't), however when the system is off you have to watch closely because it still might allow air "in". That could cause some water shifting and allow the pump pot water level to drop a bit.

Jandies are “ no lube” type

Even so, there may come a time where you may need to lift the handles off and inspect.

At lower speeds there are more/ larger bubbles no loss of prime

That is fairly common with VSPs, however it's still good to investigate all areas.

The last time we lost a couple inches water overnight the main drain was off & main drain return and skimmers were on.

Can you clarify this one more please? On your chart it would appear the main drain is responsible for allowing air into the system - a possible plumbing leak. You had the largest water level drop with the drain OFF which would also support a problem in the line (as a static test), but then you say the drain return and skimmers were on, so I'm confused on that one.

You might also consider posting some pictures of your pool and especially the equipment pad from various angles so that we can see all of the equipment, lines, valves, etc. It might give us more ideas to discuss.

 

[MiloD]

Thank you so much for your help!! I wasn’t sure if I should attach thumb nails or the whole image—> (advice for next time would be appreciated, I’m not a social media person so rarely upload photos)


* I’ve attached a picture of the tiny crack in the pump joint connector ring, you may need to zoom it. And a picture of the plumbing set up.
*The pool was build in the 1980’s it has a main drain return that is connected to the main drain ( there seems to be an exposed pvc pipe that joins the 2 (green arrows). To heat the pool faster, we turn off the main drain valve and turn on the main drain return valve ( so water goes into the pool from this line rather than out of the pool back to the pump)
* On my tests, I only lost 1/4 inch in 24 hrs when I drained the pool only through the main drain for 24hrs and zero when the drain was open but pump was off.
but when I only used the skimmers to drain the pool ( main drain off and main drain return off) I lost 1 1/16 inch over night (highest pump speeds). So it seems that the skimmers are definitely causing a problem.
*I have not been able to test each skimmer individually yet due to weather. So far I tested the deep end skimmer ( whole pool drained through it for 24hrs and I lost 9/16th) will test the shallow end skimmer tonight.
*The last time we had a “surprise” over night loss (not during a test), I looked at the valve settings and made a note. (The prior 2 times I just went into triage mode and didn’t pay attention to the valve settings.)
The valves were set to skimmers on, main drain off with the main drain line being used to return water to the pool, the water had dropped to the bottom part of the skimmers and they were sucking air.

In addition the skimmers leaking could there also be something going on with the main drain return? —> My thought is no, because of the valve configuration I assume these are all the same pipes and not 2 separate lines, so the tests I’ve done for a main drain leak, should be testing the same pipes.

I don’t know how much information would be too much, I included some details of the pool’s ”history” below incase you need it.



General information about the pool (this is our 8th season with the pool):
Sylvan built 1980’s irregular shape, with attached spa
there are deck patches behind each skimmer and the spa, no weir doors on skimmers ( some sort of plumbing issue when first built)
32k (including the spa) gunnite,
2 Main drains/ main drain return in deep end
2 return lines in shallow end
2 skimmers with floating weirs (added by us when we bought the house)
Raypak Gas heater
Resurfaced 6 seasons ago
2020 (4 seasons ago): Pentaire cartridge CCP420/ SuperfloVST pump 2.2hp
Integrated “rainbow #320”chlorine puck feeder added and “integrated pool cleaner line capped” (opening on wall in the middle of pool between the skimmers same size as the return lines)

Deck Repairs/ new tile and coping are needed:
The patch of concrete behind the deep end skimmer had been sinking for 3-4 years and the tile around the pool (starting at the curved areas and expanding has been slowly coming off since the gunnite was resurfaced 5 years ago). Also there is “ effluvecence” around the tile and coping between the spa and the pool return.

Maintenance:
Brand new Pleatco cartridges (placed at start of this season)
Solar robot skimmer/ extra large skimmer socks/ robotic pool cleaner (all new this season): run & cleaned most days
Professionally closed each year (by company that installed the filter/pump).
We open it ourselves

This year: Water level was fine on removing the cover.
Robot broke this season, used leaf/bag vacuum for large debris: followed by poolside suction to vacuum to clean small debris and dirt to open this year. (Normally just use the robot for 24hr)


Pump settings starting at 7pm:
12hr 2800
4hrs 1800
4hrs 1400