pump loses prime

[SHAYLEH]

above ground pool w/ Hayward DE 50 filter and a Matrix Pro 1.5hp pump ... installed as a single unit & it is approx 8-10 years old .. am losing prime to pump daily.. can re-prime and runs Ok until it shuts off at days end ... when it restarts the next AM, the prime is lost .. I can open the top of the pump, re-prime, & it starts right up
altho pump filter tank does not completely fill with water ... have checked and replaced the pump filter compartment glass top O ring .. no help ... fill and return lines to pool are underground and do not see any wet spots .. neither pump or filter is showing any leakage ...... how can I find my air leak ???
- shayle

 

[hrddrv]

My guess is it is one of the underground ones has a slight crack. Not big enough to leave any wet marks but just enough to lose prime. Had the same thing happen to me with a well pump. I was fine as long as there was a draw on the pump, as soon as the pump shut off the prime went away. Turned out to be a crack in the line where it went back into the ground to come to the house.

 

[Bama Rambler]

Is the equipment above the waterline? Most above ground pools have the equipment at or below the waterline.

Are there any valves in the suction line from the skimmer to the pump?
Make sure the skimmer weir is operating correctly.
Make sure the skimmer isn't creating a vortex when the pump is running.

 

[SHAYLEH]

WILL HAVE TO CHECK LINES MORE CLOSELY.......
<<< FOR DAVE J *****
have 1 valve in line which I have had checked and was told it is working correctly ... no problem with skimmer weir .. skimmer sometimes does create a vorex when starting.. have watched it and it does not seem to cause any problems ... what causes a vortex ??? is it to strong a pump ???

 

[jblizzle]

what causes a vortex ??? is it to strong a pump ???

Could be either the pump is too strong or the water level is too low.

 

[Bama Rambler]

On our pool, it will create a vortex if the weir sticks, if the water level gets too low, or if the skimmer basket gets left out. Creating a vortex means that air is getting into the filter, and if it isn't self purging, it will force air back through the pump when it's shut off and empty the pump of water causing it to lose prime.

What type filter do you have?

Since there is a valve on the suction, I would check it carefully for a leak. If you're getting bubbles in the pump basket when it's running you can run water over the valve and fittings to see if it stops the bubbles.

You said you replaced the pump basket, but did you remove and reseal the drain plug in the pump volute housing? If not it might be worth doing.