funky prime time, no main drain suction, prime off skimmers

evolverus

0
In The Industry
May 27, 2013
5
I/g vinyl liner 4 returns 2 skimmers and 1 main drain. Hayward pro sand filter and super pump 1hp. 2 valves at suction side, 1 between skimmers and 1 between skimmers valve and main drain. pump primes perfectly with no air at all when only pulling from skimmers but as soon as I move the main drain valve like three "clicks" the pump pulls air and turning valve any further than that and the pump looses prime almost instantly. I cant see the bottom of the pool but have mucked it and am only assuming there is nothing blocking it in the pool itself. I also don't detect that the main drain is connected to one of the skimmers. am I looking at a leak in the main drain line? the pool water level doesn't seem to change as though there was a leak but who knows right? oh, I also get no signs of ANY water when im pulling only from the main drain, once the skimmer lines are closed it dries up like the sahara, tried slowly suctioning air from main drain line to no avail,
 
Re: funky prime time, no main drain suction, prime off skimm

It sounds like your main drain line has an air leak. If the main drain was blocked it would not have this symptom, so most likely there is only the air leak. Presumably the air leak is above the water level of the pool, most likely quite near the valve that selects between main drain and skimmers.

You can look for the air leak by adjusting the valves so the pump is drawing just a little air from the main drain, without losing prime, and then spraying shaving cream on likely places where an air leak might be. When the shaving cream hits to spot that leaks it will be drawn down into the pipe, which is usually fairly obvious.
 
Re: funky prime time, no main drain suction, prime off skimm

thank you, now heres a kicker. I believe the pump lid oring is damaged pretty bad where I hear it leaking when the pump is off, causing my pump to lose water. I can hear the air, but would that still become an issue with the previous post even when the pump is fully primed off the skimmers with NO air present in the pump?
 
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