Hayward Sand Filter leaking Air when pump shuts off

Stukeye

Member
Mar 25, 2021
5
Oklahoma
Brand new pool owner.

After getting new liner in pool i got with house, I opened the pool, and my hayward sandfilter had a pretty substantial leak at the top mount O-Ring that's held on with the band clamp.

I loosened it, cleaned off the o-ring, and lubricated it with silicone lubricant.

After doing this, it stopped leaking water. However I've noticed that my pump is not holding it's prime after I shut it off.
While the pump is running, it takes about 30 seconds to a minute for the pump to reprime itself. There's no water leaking from the filter anymore, but when I turn off the pump, I can hear a really slow squeak from around the bandclamp and I can hear air gurgling around as it gets into the filter.


Could this leak in that o-ring just be so small that when the system is pressurized it's not leaking, but it is after the pump shuts off? Tried tightening the clamp and it did not work. Is this a sign that I should get the o-ring replaced? I'm a little hesitant to take it off and try to reseat it in the event that it just makes the problem worse and I'm stuck with no circulation until I can get a pool service tech out.
 

Texas Splash

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Jun 22, 2014
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Could this leak in that o-ring just be so small that when the system is pressurized it's not leaking, but it is after the pump shuts off?
That's a possibility. Does your filter have a pressure gauge? You might look at that as well. But no doubt hearing the hiss at the filter and water moving around at shut-down means air is getting pulled in.
 

Stukeye

Member
Mar 25, 2021
5
Oklahoma
That's a possibility. Does your filter have a pressure gauge? You might look at that as well. But no doubt hearing the hiss at the filter and water moving around at shut-down means air is getting pulled in.
It does, but it needs to be replaced as well. It gets stuck quite a bit and I have to give it a few good flicks to get it to go up to the actual pressure its reading. It is a massive filter, but it seems like the pressure creeps up awfully slow. Not sure if that's a symptom, or just a benefit of having a huge filter.
The pressure drops to zero when the pump is off.
 

Texas Splash

Mod Squad
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Jun 22, 2014
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Texas, San Antonio/Marion, South-Central Area
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Chlorine
Salt Water Generator
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Replacing the gauge is easy and relatively cheap, so that's always a good option to do first. If that doesn't resolve the hissing at the filter, you'll probably need to pull that MPV and replace the O-ring, inspecting the clamp as well. Hopefully you have enough PVC flexibility to lift that MVP off the vessel, or it was installed with unions for easy disconnect. Always stinks to have to cut lines for something like this. :brickwall:
 

Stukeye

Member
Mar 25, 2021
5
Oklahoma
Replacing the gauge is easy and relatively cheap, so that's always a good option to do first. If that doesn't resolve the hissing at the filter, you'll probably need to pull that MPV and replace the O-ring, inspecting the clamp as well. Hopefully you have enough PVC flexibility to lift that MVP off the vessel, or it was installed with unions for easy disconnect. Always stinks to have to cut lines for something like this. :brickwall:
Unfortunately no unions lol. I don't have confidence enough to cut lines so I'm just gonna have someone else replace that for me next week. I'll probably try taking it off and reseating it one more time a day or two before they come, so if I do make it worse, I don't have my pool turning green in the mean time

is that 30 seconds to a minute it takes for the system to reprime every time I turn it back on going to hurt anything other than the pump motor? I'm not too worried about that as I already have a new one ready to replace it because it's pretty loud. Just don't want to swap it out until I have this issue fixed.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,029
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
is that 30 seconds to a minute it takes for the system to reprime every time I turn it back on going to hurt anything other than the pump motor?
Many pump manuals state it can take that long to fully prime, so I wouldn't be extremely concerned about it right now. If it makes you feel better, you can pre-fill the pump basket each time to help. Maybe you'll get lucky with that O-ring, and don't forget the gauge (if applicable).
 
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