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View Full Version : Suction Leak Causes Pump to Lose Prime



donjoarm
04-13-2006, 11:35 PM
I have a Hayward Super Pump which is losing prime. I have replaced and lubed the lid o-ring without success. The pump runs fine with the valve in the recirculate position but cannot keep prime when switched to the filter position. Any thoughts?

InfinityPools
04-14-2006, 12:04 AM
Make sure also that the lid o-ring is sealing properly. A light coat of silicone lube is a good idea.

If the pump shows no signs of priming up on its own, it may be necessary to force water from the skimmer into the pump to encourage the pump to prime. This is sometimes needed if the pump is situated more than a foot above the water level

The best way to do this is by using a "drain jet" in the skimmer.

1. Hook the drain jet up to a garden hose and insert it into the skimmer line that leads to the pump. Shut off or plug all the other intakes (main drains, skimmers). This will force water into the pump.

2. Turn on the water and let it force water up into the pump trap. When the water has filled the trap, turn the pump on.

3. As the pump starts to prime, open up one of the other intakes partially in order to keep from starving the pump. This will allow the pump to fully prime. As the pump primes, open the other intakes gradually, allowing the pump to pull out any trapped air.

4. When the pump is fully primed, turn off the drain jet and remove it. Be careful that you do not allow the drain jet to be sucked into the skimmer line.

If the pump will not prime, even using a drain jet, then check the pump components for blockage or breakage.

If the pump primes, but then will not stay primed after the drain jet is removed, then check for air leaks in the system.

kaybinster
04-14-2006, 11:09 AM
That makes no sense, unless I am misreading something. You say it primes fine when you are drawing water from the pool and dumping it back in the pool without going through the filter - BUT when you draw from the pool and run through the filter it will not prime -- is that correct? Are you able to manually prime it, and if so does the water go through the filter and return to the pool? If not are you sure that you have the valving set right and you are not deadheading the pump rather than going to the filter.

I ask this because there should be no difference in the suction side to the pump when you have it set to recirculate rather than filter and the suction side should control its ability to prime. Typically when it won't prime its because of an air leak on the suction side.

mas985
04-14-2006, 11:38 AM
If your filter were to be blocked somehow or severly restricted, this may prevent the pump from priming. What type of filter do you have? Can you backwash? Can you recirculate and then change to filter without shuting off the pump?

EricF
04-14-2006, 11:51 AM
I had a very similar problem after opening the pool this year. The pump would prime, but there was an air leak. It would only happen when I closed the vacuum line valve. It turned out to be a bad o-ring in the valve, which was easily replaced. Since your air leak may be related to the valve, this is where I would look first.

EricF

donjoarm
04-14-2006, 12:00 PM
That makes no sense, unless I am misreading something. You say it primes fine when you are drawing water from the pool and dumping it back in the pool without going through the filter - BUT when you draw from the pool and run through the filter it will not prime -- is that correct? Are you able to manually prime it, and if so does the water go through the filter and return to the pool? If not are you sure that you have the valving set right and you are not deadheading the pump rather than going to the filter.

I ask this because there should be no difference in the suction side to the pump when you have it set to recirculate rather than filter and the suction side should control its ability to prime. Typically when it won't prime its because of an air leak on the suction side.


Didn't make sense to me either, but that is exactly what was happening. I just found that when I turn off the pump a small amount of water would leak from the fitting entering the pump housing. That has been corrected and now it primes no matter the valve position. Go figure.