Losing pressure

Grayman43

Well-known member
May 19, 2019
213
Rockingham, NC
Hello,
I hope I can explain this problem correctly. What is happening is I’m losing suction randomly. So when I first turned on the pump, everything is good jets are blowing well and I have good suction. after about four hours or so the suction goes down and I will go to the pool housing and see air and I lose suction. I turned on backwash and it starts working again and repeats itself a few hours later. Any ideas? I hope I explained that correctly.
 
With pump off, remove the pump basket lid. Complete clean all mating surfaces and the lid O-ring. Be sure its squeaky clean and totally free of any debris. Lube the O-ring with a silicone lube (like MagicLube II). Reinstall the O-ring in the lid and reinstall the lid on the pump. Turn on pump to re-prime the system and let us know if the issue is resolved or not.
 
I hope I can explain this problem correctly. What is happening is I’m losing suction randomly. So when I first turned on the pump, everything is good jets are blowing well and I have good suction. after about four hours or so the suction goes down and I will go to the pool housing and see air and I lose suction. I turned on backwash and it starts working again and repeats itself a few hours later. Any ideas? I hope I explained that correctly.
It is likely that you have algae, even if you can't see it. In addition to what Gene indicated, do an overnight chlorine loss test tonight. Link-->Overnight Chlorine Loss Test

You can also review trouble shooting link--> Air in the pump basket.
 
Last edited:
With pump off, remove the pump basket lid. Complete clean all mating surfaces and the lid O-ring. Be sure its squeaky clean and totally free of any debris. Lube the O-ring with a silicone lube (like MagicLube II). Reinstall the O-ring in the lid and reinstall the lid on the pump. Turn on pump to re-prime the system and let us know if the issue is resolved or not.
Thanks
 
With pump off, remove the pump basket lid. Complete clean all mating surfaces and the lid O-ring. Be sure it’s squeaky clean and totally free of any debris. Lube the O-ring with a silicone lube (like MagicLube II). Reinstall the O-ring in the lid and reinstall the lid on the pump. Turn on pump to re-prime the system and let us know if the issue is resolved or
I got the lube on the way. One follow up question. Could there be any reason why it works fine right after a backwash but it takes about 2 to 3 hours and all of a sudden the water pressure is gone and there’s tons of air in the line
 
With pump off, remove the pump basket lid. Complete clean all mating surfaces and the lid O-ring. Be sure its squeaky clean and totally free of any debris. Lube the O-ring with a silicone lube (like MagicLube II). Reinstall the O-ring in the lid and reinstall the lid on the pump. Turn on pump to re-prime the system and let us know if the issue is resolved or not.
Checked and relubed o rings. Same issue.
 

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Continue with the SLAM Process.

The below is to help determine what may be causing the air in the pump basket.

What RPM is the pump running when the air starts to form or is already formed in the pump basket?
How much air are we talking about?
About how long after priming does it take to start forming an air bubble?

VS pumps will form a bit of air in the pimp basket lid at lower RPMs. Usually it's no more than a bubble the size of the lid and doesn't extend into the basket area.

It the water level about 1/2 way up the height of the weir door?
Is the weir door sticking or freely movable be hand from closed to fully open?
 
I hope I can answer this correct. Turn pump on and basket never fills with water, but have pressure and jets just have bubbles and pump lid has quite a huge air pocket but I get pressure. About about 2 hours no pressure and jets barely moving. It’s like it gets worse the longer it runs. It problems immediately, but it’s obviously a lot of air in the basket. The water is above the weir door. After about 2 to 3 hours of running, I completely lose pressure out the jets. I’m not good at this but I hope I answered your question . After I backwash, I’m getting lots of fluid to the pool and then it slows down pretty quickly. Will need to check weir door. Water level is fine. Do you think I should check the O-ring on the suction side of the pump? Thanks for all your help.
 
I hope I can answer this correct. Turn pump on and basket never fills with water, but have pressure and jets just have bubbles and pump lid has quite a huge air pocket but I get pressure. About about 2 hours no pressure and jets barely moving. It’s like it gets worse the longer it runs. It problems immediately, but it’s obviously a lot of air in the basket. The water is above the weir door. After about 2 to 3 hours of running, I completely lose pressure out the jets. I’m not good at this but I hope I answered your question . After I backwash, I’m getting lots of fluid to the pool and then it slows down pretty quickly. Will need to check weir door. Water level is fine. Do you think I should check the O-ring on the suction side of the pump? Thanks for all your help.
OK - the filter is catching the dead algae and causing the filter pressure to increase - this in turn reduces the return flow that you are seeing.
That part is totally normal during a SLAM, especially during the earlier stages.

As for the air in the pump basket, that is another issue. You likely have a suction side air leak. We can deal with that during the SLAM or wait until the SLAM is completed.

Continue the SLAM and watch the pump basket. Backwash when the filter pressure rises 25% above clean pressure (observed at 3000 RPM or higher pump speed) - or when you notice the flow trickling out of the returns.
 

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