Pump Losing Prime

[IASteve]

I have a Pentair Superflo 1.5HP pump. I recently cleaned my filter beacuse I wwas getting filter media back it the pool. I found it had a 2" mulitport valve and a 1.5" standpipe inside, which obviously didn't seal. This allowed filter media up into the valve and chewed up the gasket, which I replaced. I installed a 1.5" to 2" PVC coupling and pipe to properly seat the valve.

Now, I have an issue with the pump loosing prime. When I turn off the pump, water rushes out of the pump back through the supplies. It only happens when the pump has been running for over 10 minutes. Occasionally it will hold water, mostly when it has been running less than 10 minutes, and I see small bubbles come up from bottom of the pump. I may have a very small leak between the pump housing seal plate - its hard to see back there. I did use a seal GO KIT to rebuild it at the beginning of the season. I just replaced the lid o-ring and it seems to seal very well. I have to pour a few gallons of water to get it to prime again.

Any advice on what to check?

 

[setsailsoon]

Re: Pump Losing Prime

Steve,

You must have an air leak somewhere in the suction plumbing. Check the simple stuff first. Do you have sufficient water level in the pool that air is not sucked into the skimmer box? If that's not it next step is to start the pump briefly and do the following but not so long that you let the pump run dry:

When you lose prime put a water stream from a hose over each connection one at a time. As you do this watch or have somebody else watch the pump suction basket to look for a change. Any change indicates you've found a leak. Be sure to flood the entire sealing surface exposure to the air, usually around the edge of lids etc. Tiny cracks in housings or bits of dirt in the gaskets can also easily cause an air intrusion leak. I recently found a hairline crack in a pump suction trap lid using this technique that I couldn't even see until it was removed, cleaned and observed under a bright light.

I hope this helps.

Chris

 

[IASteve]

I changed the oring on the drain port under the basket - same problem. I could still see bubbles coming from there. So I got a pair of slip joints and gave it a few more cranks. No more bubbles. Hope it holds.