I have been trying to solve a pool problem for months. I do believe there is an underground leak. Have done bucket test. Doing one more this week.
The problem I’m having is, the pump runs just fine without the vacuum in the skimmer line, it acts like it needs to prime every 5 seconds when vacuum is in skimmer line. So it runs fine then loses prime and then runs fine about every 5 to 10 seconds when the vacuum is in. I assumed right away there is an air leak in the hose but there is not. There is only one intake pipe. I replaced all the pump seals due to small leak. Diffuser and impeller looked alright. Could diffuser and or impeller cause this? My thought on this is a possible skimmer line leak underground where the reduced water flow with the vacuum in skimmer line causes fluctuation in water flow to pump. Desperately need suggestions. I’ve never had issues solving a pool problem until this started. Vacuum worked fine for years. This happened before Opening pump. Also found and fixed all air leaks in valves and plumbing. No intake valve, 1 pipe.
Pool has
- Skimmer
- Main drain
- In deck leaf catcher
Pool is infloor (Needs repair so it’s not used).
Hi Terrance and welcome! We are sorry to hear of your issue and we know all too well how frustrating it can be to find a leak.
It sounds like you checked all of the usual suspects, so I would guess that the extra suction pressure in the skimmer plumbing caused by the vacuum line is either sucking in air from a bad plumbing joint or there is a small crack in a pipe since it doesn’t suck in air under normal operation.
How quickly does the pool lose water? If it is a noticeable amount after a day or 2, add liquid chlorine to shock level or above and then turn the pump off. Isolate the skimmer lines (either with a screw-in plug or stopper - don’t forget to isolate the line at the other end at the pump) and let the pool sit with the pump off while performing the bucket test. The skimmer line is the culprit if the water levels stay the same.
If this were a new issue or if something changed (new higher-HP pump) it could be cavitation but it sounds like everything was fine until recently. An issue with the impeller or diffuser would not cause this issue.
I sincerely hope that the leak isn’t in the skimmer line since these are very difficult to repair on an inground pool. Keep us updated and let us know what you find.