Who likes a good puzzle? (losing prime)

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T

timell

0
May 17, 2007
9
Austin, TX
I know the solution may not be difficult for the pros, but I'd like to learn too. I've been chasing this for two weeks

a few weeks ago, the pool started losing water. One of the return lines to the pool snapped at the pool wall and I lost a significant amount of water. The water level then proceeded to dip below the skimmers and then I sucked air into the system. This caused prime to be lost and had the pump running dry for a few hours.

The leak has been fixed but now my pump will not hold prime overnight. I have to manually prime it from the spa every morning.

Things that I've done to the equipment.
1. noticed that pump was "burping" water every time I turned off the pump. So I went ahead and replaced the o-ring. light lube and tightened the thumbscrews. I did notice that the o-ring seemed to be thicker than the one I replaced, but both pool stores said that I had the correct one for the Hayward Super II pump. even after replacing the o-ring, I still get a "burp" when shutting off the pump. This is my prime suspect for the current air leak.
2. A small amount of water was puddling at the threaded output pipe of the pump. So I removed the pipe, added more teflon tape and all seemed good. After a few days, there was still some water weeping out. Quick, go to trouble free pool forums. So I removed the pipe again, wrapped another turn or two of tape and added some oatley joint compound. Seems to have fixed the problem.
3. opened both check valves and removed any debris that may have collected, lubed and replaced. Both of them never leaked any water, so I have no reason to believe that they are the source of the air leak.
4. hand checked the pump drain, no water and no loose screw. did nothing to this.

Observations.
1. If I prime the system, shut off them pump and turn my jandy valve to the spa. All of the skimmers and drain will hold water behind the valve.
So in the morning, I'll have the pump prime itself from the spa, and then I'll switch the valve to the pool. No water bubbles at all on the valve switch.
2. Once the pump is primed, there is never any bubbles coming through check valve #1.
3. There is no water leaking anywhere that I can detect.
4. I can see a churning of water through the pump basket lid.
5. Last night after I shut off the pump, I watched and listened to see where the water was going, after about 5 minutes check valve #1 started losing water while check valve #2 still stayed full. Overnight, both the check valves would eventually drain.
6. After careful inspection of the pump body and lid, I see no evidence of cracking or warping. There is some deposits here and there but nothing in the area of the o-ring and lid seating area.

Conclusions.
The air leak is somewhere between the Jandy valve and the second check valve. My guess is the pump lid, but I don't see anything that drastically wrong with it. My second guess is the difference in thickness of the o-ring that I replaced. Not knowing the equipment well, I'm taking the pool stores advice that I've got the correct one. The reason why I question this, is that when I turn the thumbscrews on the lid,
I don't have that feeling that I'm getting a great seal. This may be the case or me wishing that it's the trouble spot.

So what am I missing that's causing an air leak? My next move may be to buy a new pump lid. ugh!

Thanks,
Tim

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JohnT said:
The squirting from the lid tells you it is the lid leaking air for sure. Could be that the housing warped.
Click to expand...

I don't know. I had the Hayward rs pump that looked like the same lid. It always squirted water when the pump turned off, but never sucked air or lost prime.

Posted from my Droid with Tapatalk ... sorry if my response is short ;)
 
Your trobleshooting certainly leads to somewhere between the suction check valve and the impeller. I'm guessing the pump lid. Over tightening the thumb screws can cause it to leak by warping the lid over the o-ring.

I'd lube the o-ring really good and snug the screws down a little at a time and see if the problem stops at some point.
 
Thanks for the suggestions everyone,

I went ahead and removed the lid, examined it, re-lubed the gasket and put everything back together.
Nothing at all is looking damaged in the pump body or lid.

After starting up the pump and letting it run for a few minutes, I noticed air bubbles still dancing around in the pump lid.
The check valves were bubble-free. (strike one against the lid)

I then turned off the pump, didn't notice any water "burping" out, though the lid did shift/move a little, as did the multiport valve handle.
I believe this is normal.

Almost immediately, I started hearing the glug-glug of a leak. Sure enough, the air bubbles were getting larger
in the pump basket lid, while no change/no bubbles in the check valves. (strike two against the lid).

Now if I had waited and let the water level go below the lid, I should stop hearing the glug-glug sound and water would silently drain out of the pump basket if the leak was at the lid? Correct? I didn't wait to test that theory.

Thinking that maybe the lid was warped, I turned the lid a 180 degrees when placing it back on the pump. While
this did not fix the problem, the bubbles did appear to come from the same side of the pump housing irregardless of what orientation the pump lid was installed. Who knows if this is significant or not.

Barring any other ideas, I think my next step is to replace the $50 lid.
The only other explanation is another part of the pump body is leaking air. I don't know how that can be the case, when I would expect water to be leaking also.

Thanks again everyone for help on this,
Tim
 
Since turning the lid around did not change anything ... what are the odds the lid is warped symmetrically? That almost makes it sound like the pump housing in one area is warped.

Your problem is loosing prime, not necessarily the bubbles in the pump basket. In some cases it is fine to have bubbles in the pump when running (as long as they do not get bigger when the pump is off .. your problem).

My current 2 speed will have the water level in the pump get lower and lower ... no air in filter of going to pool. If I switch it back to high speed, the air will be purged to the filter and fill the basket back up. I think the extra suction seals the lid better ... although I still do not have the water go down when the pump is shut off.
 
Did one last experiment before my trip to buy a new pump basket cover.

I primed the pump, and filled the system with water, stopped the pump, and then waited as the glug-glug sound drained
the pump basket. This time I waited while the water lowered and then once it got a little bit below the
pump cover level, the glug-glug stopped but the water level continued to drop and finally empty check valve #1.

This tells me that the air leak is coming from the pump lid.

Anyways, I go to the pool store and tell the guy that I need a pump lid cover because my pump ran dry for a certain amount of time.
Either he wasn't listening or only heard "pump ran dry" and was convinced that my problem was with the impeller that had melted due to the pump overheating and wasn't working correctly.

I ask him, that even though the impeller may be warped, how is air being introduced into the system. We didn't quite get to the same level.
I then proceeded to tell him my theory and that the lid may be warped. And he said that in all of his years, he's never seen a warped cracked pump lid.

So, my question is, how frequent does pump lid warping occur? Am I about to spend $50 and not fix my problem?

The pool store guy wanted me to disconnect my pump and bring it in so they could test it. I'm not crazy about taking apart the pump, but if a new pump lid won't solve my problems, then that's the next step.
 
After you shut off the pump, take a hose and run water over the pump lid. If it is leaking from the lid it will suck water in and you won't get air in the pump basket.
I think you may have air coming in from the mechanical seal. The ceramic seal needs water to remain cool, if it ran dry the sell face could have been damaged.
 
Running a pump dry for a few hours can cause the basket and/or lid to warp. It can also cause warps and cracks in other places. I suspect something on the pump has warped. I can't be certain whether it's thed lid or not, but that's a good place to start. It could be the basket wall and that's why the leak didn't move when you turned the lid around.
 
UPDATE:

Well the problem isn't with the lid. After swapping out lids, I was able to further narrow down the problem. The new lid did give me a "clear" view of what is going on in the pump basket. The "glug-glug" bubbles were not coming from the lid, but from the input port of the pump body. This is why when I switched the lid 180 degrees, nothing changed.

So this puts the problem somewhere between the check valve and the input port of the pump. Well, there's only two possibilities, the threaded pipe union at the pump and the glued union at the check valve. Since the bubbles were showing up in the pump lid instead of the check valve, I'm guessing the problem is with the threaded pipe union.

I put some soap and water around the union and nothing unusual showed up. Because there is no way with the plumbing to easily remove the threaded pipe, retape or add thread sealant, I have to come up with a different solution. So just for a test, I put silicone caulk all the way around the joint. I know this won't hold pressure, but since this joint wasn't leaking water, maybe by chance it would cover an air leak. I won't know until I check later today, but just after caulking the joint for the first time there were no bubbles in the pump basket lid with the pump running. Before there was always 1-2 bubbles dancing around the lid. Hope springs eternal.

Who knows, it seems strange that at this joint that there would be an air leak but not a water leak.
 

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timell said:
UPDATE:

Well the problem isn't with the lid. After swapping out lids, I was able to further narrow down the problem. The new lid did give me a "clear" view of what is going on in the pump basket. The "glug-glug" bubbles were not coming from the lid, but from the input port of the pump body. This is why when I switched the lid 180 degrees, nothing changed.

So this puts the problem somewhere between the check valve and the input port of the pump. Well, there's only two possibilities, the threaded pipe union at the pump and the glued union at the check valve. Since the bubbles were showing up in the pump lid instead of the check valve, I'm guessing the problem is with the threaded pipe union.

I put some soap and water around the union and nothing unusual showed up. Because there is no way with the plumbing to easily remove the threaded pipe, retape or add thread sealant, I have to come up with a different solution. So just for a test, I put silicone caulk all the way around the joint. I know this won't hold pressure, but since this joint wasn't leaking water, maybe by chance it would cover an air leak. I won't know until I check later today, but just after caulking the joint for the first time there were no bubbles in the pump basket lid with the pump running. Before there was always 1-2 bubbles dancing around the lid. Hope springs eternal.

Who knows, it seems strange that at this joint that there would be an air leak but not a water leak.
Click to expand...

It's the suction side - so no positive pressure - right? If the leak is on the top of the joint I can see how no water would come out (air being pulled in during pump operation) and then air would leak in (water levels drop as water air flows in - only if pump is above the waterline...)

Before I came to be a BBB'er and I helped my neighbor with his AGP I helped him find some suction side leaks that were giving him fits. We used electrical tape. It is stretchy and seals well - and the leaks vanished. He never had water come out - only air going in. His pump was below water level. Air leaks in more readily than water leaks out. But his problem was not losing prime - just air churning in the pump basket.
 
Timell, I am having the same issue with my set-up. I have checked the pump basket o-ring, removed and cleaned out the check valves and still losing prime...I have heard from a pool professional that you can purchase a drain king from a hardware store hook it up to the hose and place it in the suction side of the skimmer and turn on your water hose and place pressure on the system and it should show where the leak is...My problem with this theory is how will it create pressure, I would think that the water would flow past the pump and not be affective. It may be worth a try, just a thought.
TRW
 
UPDATE:

Came home tonight after the pump had been turned off for 2 hours and surprise, the pump basket still had water in it. I think I found my air leak and it was was at the threaded pipe union into the pump.

After closer inspection of the caulking job that I did this morning, I found what looked like two pinholes at 10 o'clock and 11 o'clock when looking at the pump input pipe. I'm thinking this is where the pump was sucking air/caulk into the system. I applied some more caulk at these locations and will see what happens in the morning.
 
TRW said:
Timell, I am having the same issue with my set-up. I have checked the pump basket o-ring, removed and cleaned out the check valves and still losing prime...I have heard from a pool professional that you can purchase a drain king from a hardware store hook it up to the hose and place it in the suction side of the skimmer and turn on your water hose and place pressure on the system and it should show where the leak is...My problem with this theory is how will it create pressure, I would think that the water would flow past the pump and not be affective. It may be worth a try, just a thought.
TRW
Click to expand...
If you have a multiport on your filter you can set it to closed.

-sent with Tapatalk 2
 
I have a long and continuing puzzle as well - I used plumber's putty on all joints I could see - some got sucked thru the lid's O-ring. Bingo! #1...

I have another Q for those who've dealt with leaking fittings such as this:

Would PVC cement applied as Timell?'s caulk or my putty be a permanent, if sloppy fix? Since it creates a weld, it seems like it should.
Yes, it WOULD defeat the purpose of having and open-able fitting. The price we pay...
 
In my case, I used bath and tub caulk around the joint and after having some of it sucked into the joint and then repatched, it seems to be holding stable after 3-4 days. I'll monitor for a little while longer but for the past few days, the check valves were full right before the pump turned on for the day; instant prime.

In three spots where after initial application, I had some of the caulk sucked into the joint. Two were pinholes and one was a few millimeters wide where it looked as if I missed a spot. (maybe I did), but after reapplying, all is well.

If the pipes were plumbed better, I would have removed the threaded pipe and used teflon tape and joint compound.

Thanks again for everyone's help,
Tim
 
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