I'm hoping someone can shed some light onto what's going on with my pump. I've been searching and searching the forum for the past few hours, but can't find anything that's quite like my situation.

Pump: A.O. Smith Centurion 1.5HP
Problem: pump has been manually turned off for the past 2 weeks. Tried to turn it back on yesterday to start fighting an algae attack. It would turn on for several seconds (sounded like a grinding noise) and then switch off. I'm assuming it was the thermal trip. After several attempts, and waiting for the weather to cool off (110* Vegas sun!) it finally primed and water started coming out the relief valve and started running smoothly.

We need to drain the pool to get our CYA levels down, so we switched the pump and drained to waste. We turned it off last night around midnight and this morning, when trying to turn the pump back on for another round of draining, it's doing the same thing--starts for several seconds, and shuts off. Only today, I've covered the pump with bags of ice to keep it cool, and after way more attempts than yesterday, it still won't "kick over" and get going.

I've tried running hose water over the basket area while starting the pump, to no avail.

Up until now, the pump has been working just fine, been on a timer, running 10 hours a day. It was manually turned off 2 weeks ago and now it won't start back up normally. One thing I am wondering...last night after turning the pump off, I left the relief valve open. Could this have allowed air into the system and caused it not prime now? Or could the open valve have caused problems in another way?

Any and all help is appreciated, as we are trying to fight an algae outbreak and can't do so until our pump is working

Is it still making an odd noise?

Leaving the air purge valve open would have allowed air into the pump and will make it hard to prime.

Yes, it's still making a grinding noise, then shuts off. I knew I shouldn't have accidentally left that valve open. Blast! Any suggestions on how to get it primed again? I'm desperate! TIA!

If it's making a grinding noise, the bearings may be bad. The impeller could also have problems.

It was doing this yesterday--same grinding noises--and once it finally started up, the grinding noise stopped & the pump ran smoothly. If the bearings were bad, would the grinding noise stop or continue? I have also already checked the impeller by hand and it is turning fine.

Maybe but they still could be bad. It could be the pump cavitating when trying to prime.

I am going to wait for the temps to cool off and try again....

It's still not working...we even switched out the capacitor and that didn't help either. I feel like it just needs to be primed and has tons of air in there, but the normal priming methods have failed. Anyone have any other ideas?

On my Hayward pump there is a plastic guide ring that helps hold the propeller assembly in place that getting a little beat up from the plastic on plastic contact. I have put that back in the wrong way and when i started the pump it seemed to have a grinding sound. Once I flipped it back in the right place it sounded fine. Not sure if your pump has this but that support might be going bad and causing binding in the pump then shuting down from heat. I have to take mine apart sometimes when turning my pool because junk gets in the propeller that slips thue the basket,

Me, too. I believe the grinding noise you are describing is misleading and it simply is making that noise because there is no water to the pump.

1. Have you been able to prime the pump easily enough in times past?

2. Can you post a pic of the equipment so we can see valves, piping, height relationship to the pool, etc?

Yes--the pump has never had a priming problem before this. Here are some pics of the equipment. The pump/motor/filter is located 30 ft away from the pool and is at the same height as the pool deck.




I also made a little YouTube video of the what it sounds like when I turn it on--you can hear the grinding sound and then hear it trip off. http://youtu.be/Y6Kp07V5mgk

We replaced all the o-rings and gaskets--didn't make a diff. Checked the impeller--turns freely, no debris. The strange thing is, when we turn on the pump, it doesn't suck any of the water from the basket. Any more insights or ideas? We are desperate!!! Thanks!!!