Pump will not maintain prime on pool side

[chuckj]

I have an in-ground, gunite pool with attached spa. A few weeks ago a freak occurance caused the spa to drain and the pump to run without water for several hours. I have replaced all of the seals including the ceramic one in the pump. When I activate the system I can get good pressure on the spa side but when I switch to the pool side the system loses pressure and won't create or hold prime.

I have filled the basket in front of the pump with the hose to back fill the line but it does not help. I've tried just using the skimmer line or just the main line with no luck. I've also put a water jet in the skimmers to flush water back toward the pump but with the same result. This weekend I tried starting with the spa side and just gradually switching the pool side to see if I could get the suction working on the skimmer or main drain and when I go past 50% cut off on spa the pressure drops to zero. If I restore the spa line it comes back to life.

I'm open to any suggestions.

Thanks.

Chuck

[dynamictiger]

One of the seals you changed on the pool suction is leaking air.

HTH

[chuckj]

Thanks. But a question. The only seals I changed were in the pump itself and the pump works fine in spa mode. Wouldn't it perform poorly in spa mode as well?

Chuck

[dynamictiger]

The seals in the pump may be okay. It is most likely a seal or o ring on the pool suction side