Our 1.5 HP pentair challenger pump isn't holding its prime

since it's a new install is voltage set correct on motor ? this seems possible due to short run time you report

check the impeller for debris. you will have to take the metal band off that connects the wet end to the seal plate. inspect the impeller for debris. lube all o-rings and reassemble. if that does not work, investigate a blockage in the suction side plumbing.

you..you need to lube the seal, it may be that the seal has been damaged by chlorine and may need a new one, these pumps are fragile so do not over tighten the ss band ,tap it lightly with a hammer as you tighten it all the way around..and prime THE PUMP WITH WATER AFTER ANYREPAIR !

check amount of water pumping if pot is not full you could have somthing in the impeller like small leaves

http://www.poolplaza.com/C-Challenger-High-Pressure-Parts.html

most common problems...dirty filter and/or clogged impeller

This could be many things, first Check your lid "O" ring if it is cracked or streched it will need to be replaced. If it is dirty clean it and the pump lid and pot rim with some soapy water and an old tooth brush. Although everyone is told to lube their "O" ring on the pump on a regular basis, but no one tells them to lube it then wipe it down. You don't want excess lube on it just enough to keep the rubber soft and a little slick. Other wise it will collect dirt and won't seal. Of course if you haven't been lubeing the "O" ring that could be the problem also. Other than that the problem will be a bad seal or the pump needs to be replumbed.

Where is the water leaking from and does the noise start only when the pump starts or the entire time its running..