Pump doesn't prime evry time!

[raebrown63]

My pump is about 8 years old and has worked well until recently. I have a 20k salt water in-ground pool in Phoenix, AZ.

I've noticed a steady drip each time it runs and lately it's doesn't prime every time it turns on. It primes sometimes and not others. The pressure is at 0 when it doesn't prime and about 30 (which is correct for my pool) when it's primed. The skimmer baskets are free of debris.

Comments? Suggestions?

 

[Bama Rambler]

Is the pump basket full of water when it primes and is running?

 

[raebrown63]

Yes - the pump basket is full of water when it primes and is running. When it doesn't prime the basket does NOT have water in it and I have to fill it then turn on the pump and it works correctly.

 

[Bama Rambler]

It sounds like you have an air leak.

Where is the drip you see when it's running?

The pump basket lid and drain plug are common places to have an air leak.

 

[Christian]

Have you checked your weir gate to make sure it's not getting stuck in the upright position?

 

[raebrown63]

The wier gate is operating correctly - thanks for that suggestion.

 

[raebrown63]

I had to prime yesterday, so I made sure the skimmer basket was clean, the pump basket was clean and the round piece at the bottom of the skimmer box was in place. I filled the pump basket with water, secured the lid back on and started it up obtaining nromal pressure.

I sat by the pool for about 10-15 minutes and watched the in-floor cleaning cycle - at first a ton of air (as expected) but after about 10-15 minutes, no more air was coming out of them.

I watched the pump and it's leaking from the seam where the front and back of the pump are screwed together. I looked again at the end of the 6 hour cycle and it was still leaking from that seam - I didn't see it leaking fromt he basket lid or drain plug.

 

[Bama Rambler]

You can have an air leak that doesn't leak a drop of water. Having said that, I'd get that drip repaired, but you still need to find the air leak.

 

[RPS&D]

If your pressure is at 30 PSI it suonds like your pump might be de-priming when you turn it off. When you turn it off do you hear the water running backwaards through the pipes and see bubbling in the pump basket? If so, clean your filter or backwash if you have a sand filter.

 

[raebrown63]

The pressure is supposed to be at 30 - that's the expected pressure for my pool & sand filter. At any rate, I primed the pump filter basket again, had the pressure to 30 PSI & then turned it off. It definately sounds like the water is running backwards and the pump basket emptied and when I immediately tried to backwash, no pressure and no water. Then I closed the valve and turned the pump back on - after about a minute the water began to flow and achieved a PSI of 30 again.

My bottom line question: is this a pump issue or something else? The pool has never had this issue in 8 years.

 

[jblizzle]

It is an air leak issue ... whether the leak is on the pump or some of the plumbing is yet TBD.

After you get the pump primed and running, do you open the air relief valve at the top of the filter to remove all the trapped air from the filter? If you do not, that air can be compressed and when the pump turns off, this air can push the water back into the pump ... although that should not in itself cause the pump to loose prime.

There is likely an air leak on the pressure side that is allowing the water to drain out of the filter and pump when it is off that causes the loss of prime.

 

[Bama Rambler]

Tell us more about your equipment. Pump model, Filter model, multiport or slide valve, etc..

As JB said, air getting in the filter will push water backward out of it when the pump is stopped, but the air is coming from somewhere and about the only place it can get in is a suction side leak. One other possibility is that the multiport valve could allow air in once the pump stops if it's leaking. However if it is leaking it should be leaking water out whenever the pump is running.

Once you get it primed, open the air bleed if it has one and see how much air comes out before the stream is completely air free. Then once it's ran for a little while open it again and see if you get more air out. Post back what you find.