Pump not priming

Hello all, at the end of June I replaced the old cartridges in my Hayward C5025 with new ones. I opened and closed the unit as I had done many times before to access/clean the cartridges. Upon turning the pump (Hayward super pump 700 series) back on I noticed a small leak at the clamp system where the upper and lower filter bodies meet. The leak stopped when water started coming through the air relief valve but I decided it might be best to go through the process again. No leaks but…

In short I’ve had issues with the pump not priming since then. I’ve had my pool service out twice, they’ve inspected and lubricated o rings, tightened the clamp and installed a new air relief valve. It was priming for the last week or so since their last visit, albeit kind of slow - I was not seeing water coming into the pump strainer basket until about 40 seconds after the pump turned on and water didn’t start coming out of the jets until about 1:40. Yes, I timed both. Unfortunately, today it didn’t seem to be priming at all so I had to turn the pump off and fill the basket with water, just like I was doing throughout late June/early July.

My pools guys think it is possible that the underground pipes have been breached or damaged by the roots of a large bush that sits between the pool and the equipment so I am prepared to have this removed in the Fall so they can access the pipes. My concern is that everything was fine until I opened the filter up as noted above so it seems to me I caused an air leak somewhere on the equipment side that has yet to be detected. I should note that when the pump turns off at night there is a rush of water from the filter/pump to the pool that basically pushes out the skimmer baskets and covers.

Thanks in advance

Question. Is there a consensus re lubing the large metal reinforced seal that sits between the upper and lower filter bodies?

Are you referring to the Tank Lid Metal Reinforced O-ring - DEX2422Z2 used on the

The manufacturer recommends cleaning the sealing surfaces and using a very light coating of that o-ring with a silicone-based lubricant such as Magic Lube - 1 Oz. (silicone based) - 650.

Yes, that is the part. The reinforced o-ring.

I actually checked and the pool guys did lube the o-ring. Pump still not priming so not sure what the issue is.

I’m sorry to hear that.  You said that there is a large enough rush of water to push out the skimmer basket and covers, so it has to be a relatively large leak; I can’t imagine it is coming from the filter gasket, since that would be pretty obvious since it would squirt water out like crazy when the pump was on.

Be sure that the filter was reassembled properly and that your air relief valve is operating properly.  Does it release the air that gets trapped in it after everything primes?  If the air stays in the filter, it will act as a compressed air canister and blow out the lines to the skimmer when it is turned off - and make your pump struggle to prime.  Can you hear a whoosh of air coming from anywhere when the pump is turned off?

I would doubt that the lines from the skimmer have any issues.  Can you shut off any lines to or from the pool when the pump is turned off to isolate the lines from the skimmer?  That would help prove that those lines are okay.

Thank you for your response. I recently replaced the air relief valve itself, not the entire air relief assembly, but everything seems okay there. I replaced the valve as I did experience a slight leak there upon reassembly/restarting the system back when I first started having issues. It now seems to operate as intended after the system is reassembed and restarted. That said. twice, in trying to troubleshoot this situation I opened the air relief valve while the system was running and water did not immediately come shooting out as I would expect, it actually took close to 45 seconds/a minute for a full stream of water to come out. I thought of this after reading your post where you mention air staying in the filter canister.

I will go out by the unit tonight when it turns off to see if I hear any air coming out. I think thus far I’ve been a ways away from the unit so I’m only hearing the rush of water back to the pool.

No, I do not have any way to shut off or isolate the lines coming in from the pool.

Not having a valve should not be an issue.  I’ll bet the air relief system isn’t “relieving” the air and it is building up in the filter.  It should not take that long to get the air out of it (and you have found the issue if you bleed the air out manually and don’t get the blowback).  Please be sure to update us if that is (or is not) the issue!

Thanks again for your replies. A potentially dumb statement/question but just to clarify, on a daily basis I have never done anything with the air relief valve. In theory I only open it before disassembling the system to clean or swap out the filter cartridges then close it once the filter canister is reassembled, system turned back on and fully primed (ie once I get a full stream of water out of the air relief valve I close it). The system is then primed and the pump pulls water to the filter daily without any intervention. I don’t open the air relief valve again until the next cartridge cleaning.

That out of the way, are you thinking the air leak is at the air relief assembly and/or at the valve based on the behavior I’m experiencing? Also, does it seem odd to you that the pump was priming fine until I opened/closed the system? Or is it just a coincidence?

I think that the issue (either an air leak or the air not being able to escape) is at the air relief valve or something might not be assembled correctly so the trapped air that gets in there can exit the filter.  You mentioned that you  “recently replaced the air relief valve itself” so that’s why I was thinking that the issue could be with the valve.

You are correct - generally, you only need to fiddle with the air release valve when the filter is serviced.

An air lock in the filter can cause the pump to take longer than normal to prime.  Don’t forget that the pumping and filtration system is a closed system so air should not get in there on a regular basis; pumps should only need to be primed after something has been serviced unless there is a leak somewhere.

I replaced the air relief valve after the priming issue began because I experienced a very small leak at the valve upon reassembling. No change with priming with the new air relief valve. I’m wondering if the entire air relief assembly should be replaced.

I did listen for air leaks last night when the pump turned off but did not hear anything. Honestly the rush of water from the filter back to the pool is so loud it’s not surprising.

I just stumbled upon a video we have that addresses your exact issue - Why is my skimmer lid blowing off?  One thing they mention that I neglected to was to check to see that all of your valves are open completely on the other side of the filter (not just the suction side from the skimmer).

I would still recommend checking to be sure the filter was assembled properly so that any air that gets in it can get released.  Here is the manual for your SwimClear filter to show you how to service and assemble it.

Thank you. So still trying to troubleshoot  I’m thinking of potential culprits. Air leak at the air relief assembly, air leak at the filter drain plug, air leak in the pipes/joints between the pump and filter, or air leak at reinforced o-ring.

The most likely culprit seems to be the air relief assembly as I would expect water leaks at some of the other areas I noted. Also, I’m fairly certain the reassembly was ok. I’m pretty methodical about it and still review the manual each time. Also, my pool service also opened/closed to lube the o-ring/ensure the clamp was tight enough so I’m thinking an air leak there can probably be ruled out.

I don’t have any valves on the return side so everything is open there. Both jets have good pressure although I do have a lot of bubbling, with the air coming through the jets being audible, if that makes sense.

It is hard to be 100% sure without actually seeing it but I think my issue is that Hayward has changed the design slightly since your installation.  When you open the Filter Head, you create a gap between the lower valve and the upper valve. Before that gap got sealed by the new gasket, air was sucked in. After the gasket was installed, there was no air to be sucked in, hence the leak.  Even if there was a leak, the pool water itself could not have gotten in the filter. So if your pump fails to prime, your pool water is not compromised. However, if the pump continues to run, it could suck down the ground water below the pool, which would make it troublesome to pump the water out of the pool during the winter season. Until pump is primed, I would NOT leave the pump on for hours on end, just in case.