Pump primes but 30 minutes later it lose prime high psi

[brown]

Hi
When I turn on my pool pump it primes well psi at 30 and suction and return jets are strong. 30 minutes later the pump suction is lost and the pool circulation is lower or no circulation at all. The pool pressure still remains high at 30 psi. I notice that there is no water in the pool pump and I hear a bubbling sound in the top of sand filter. I have changed the sand, I have made sure that the air bleeder is in the correct spot and is not clogged, I have checked the O rings of the pump basket, the jandy valve and mpv and they were lubed as well. I have tried to blow out the line with the water hose and bladder. I have also used a shop vac, at both the skimmer side and pump side, I have checked the pump fan to make sure there are no sticks or twigs. When I turn the pump valve to the skimmer or main drain the pressure will drop to 25 psi for both sides. Is it possible to have an air leak?? I have sprayed water on the pipes but there were no signs of air leaks. Is there any advice that will help me I'm about to go nuts with this pool. Thank you in advance.

 

[Bama Rambler]

You say that it's losing prime, but then you say that the pressure stays at 30 psi, is this correct?

You also say that there is no water in the pump basket, is this correct?

If the pressure is staying high, then it's not losing prime. It sounds like the filter is clogged and stopping flow.

Are you sure that there's no water in the basket, and that it's not just completely full of water. Sometimes if the pump basket is completely full it'll look empty.

By turning the suction from both skimmer and main drain to either one it's normal for the pressure to reduce a little due to the higher suction pressure.

What does the water look like?

Can you post a set of test results and how you got them?

 

[brown]

Yes, the pressure remains high but when i look through the pump l no longer see water touching the lid and you can hear bubbles inside of the sand filter.

When I open the pump basket there is water but not enough. The water level is really low and it sounds like it's being sucked from the basket. I have the correct water level in the pool.

When I start the pump I can see the water moving through the lid. When it lose suction I can tell because I will no longer see the water, the return jets no longer have pressure and it sounds different.

The water is green, and I have not done any test. I do know that the chlorine level is high.

Also the normal psi for my pool is around 20 psi
Thank you for your response.

 

[pooldv]

Sounds like a suction side leak. More here on tracking that down, Pool School - Suction Side Air Leaks

 

[JohnT]

Try running with the filter on recirculate and report your gauge reading and see if it keeps running.