Iíve been visiting the forum for the past few years for all my cleaning and pool chemistry needs Ė I cannot tell you how much I appreciate all the information and help!
I recently installed a Pentair VS pump (011018) and Iím having a few issues. If someone has time, any help would be greatly appreciated!
(i) While the pump is running, air slowly and constantly builds in the strainer pot. Typically, it isnít bad enough to see air coming out of the returns; however, after running for a time, especially on lower speed of ~ 60 gpm or less, I will eventually start to see air bubbles in the pool. Further, when the pump is shut-off the strainer pot almost fully drains over time. I know a small amount of air can be normal for VS pumps, but losing prime when its off I think indicates a suction side air leak. Iíve checked and lubed the lid O-ring and the basket drain plug. So my next best guess is that the male adapter on the pump inlet is not quite air tight - the discharge male adapter has a very small leak as well. I was thinking about replacing the adapter and using a Teflon based, non-setting thread sealant instead of Teflon tape, which I previously used.
(ii) When trying to fill the strainer pot for re-start, water constantly flows back into the inlet piping and essentially never fully fills up. From reading on the forum, I believe that I need to install some check valves at some point. Regardless of this issue, I can fill the pot up to the bottom of the intake pipe (about 60% full) and the pump normally primes within 1 minute. Priming mode is set to 1% sensitivity. Note, I had the same issue with my old single speed pump so I do not think its related to the new install.
A few questions:
Does it sound like I am on the right track based on these symptoms or is there some other trouble-shooting I need to do? Is it correct that the discharge leak cannot cause this?
If I reinstall the male adapter, is it acceptable to have a coupling or union inside of the 2X diameter straight run required for the pump inlet line? It is currently 2XD (10Ē), but once I cut to replace the male adapter I would obviously lose some length. Would it be better to have a completely unobstructed but shorter inlet run, or the full required 2xD with a coupling or union? Iíve reached out to Pentair both by phone and email trying to get their recommendation for this but havenít had any luck.
How necessary are the check valves? If my pump is priming in such a short time am I still risking damage by starting it without the strainer pot being full?
Thanks again and sorry for the novel!