Broken 2" PVC elbow on Aqua Genie return line

[RaginCajun]

I just finished repairing a broken elbow on a 2" PVC line that returns water to the pool through an Aqua Genie skimmer. The pool is three years old and the line is about two feet underground. The break was beneath the concrete pool deck which made it difficult to repair. The pool equipment is pretty far (~50') from the pool, so there's a pretty long run of PVC before the water made a 90 degree turn up into the skimmer. I have no idea how or why this elbow cracked other than possibly just a defective piece of PVC. If that's the reason, why did it take three years to break?

When I discovered the leak and broken pipe, I was looking for a problem on the suction side that was causing my pump to not prime. Despite my best effort changing the pump cover gasket, lubing the gasket liberally, and applying a silicone bead to the pump inlet piping, I couldn't get the pump to prime. Now that the broken pipe is repaired, the pump primes fairly easily.

It doesn't seem to me that the broken pipe on the return side of the pump would affect the pump's ability to prime, but I must be missing something. Could someone please help me solve these two mysteries? (1) Why did elbow break and (2) why did repairing it allow my pump to prime. Thanks!!

 

[Guest]

If it was at the skimmer like you say, then you were most likely drawing air which would not allow it to prime. It doesn't take a whole lot of air to lose prime.

When you say the elbow was broke, what do you mean? I've seen pipes crack down the length of the pipe and not be a problem for years. Sometimes the manufacturer produces a pipe or fitting with a hairline crack that runs the length and is not visible. Perhaps that was the case with this one

 

[RaginCajun]

Thanks for the fast reply, Bruce. The break was clean through the elbow, not on a run of straight pipe. The elbow broke into two pieces, the break was right in the bend. It was at the skimmer assembly, but since it's an Aqua Genie, the return and the suction under the basket are in the same unit. I verified that the break was in the line that returns water to the pool from the filter. Since that's a completely separate run of pipe than the suction side, I don't understand how that could have affected the pumps ability to prime.

 

[waste]

Welcome to TFP!!

What follows is only an educated guess-

Though a defective elbow is possible, is there any chance the deck 'heaved'?

What may have been causing the priming issue is the crack in the elbow would allow the system to loose prime, by allowing air into the system. People with return side air leaks often have a similar problem.

I hope the new elbow has completely fixed the problem and the pool will give you no more trouble!

 

[RaginCajun]

Thanks Ted. I'm not sure what heaving is or what causes it, but would it be related to freezing temps causing the soil to shift? It doesn't get that cold way down South, but maybe it was just cold enough? The deck itself didn't look different.

I wish I could understand how a break in the return line 50' from the pump and with all the other equipment in between could allow enough air to enter system to prevent the pump from priming. I don't doubt that it's possible since I've witnessed it. It just doesn't make any sense to me. That elbow was almost 2' underground too!

I just had the seal replaced on my pump, so hopefully I'll have a trouble free pool in the near future!

 

[RaginCajun]

Here's another little tidbit to make my story more interesting. The pressure gauge on my filter is reading 0 psi even though everything seems to be working well. I can feel water rushing out of the Aqua Genies, water's getting pulled through the skimmer basket, the pump (with a new seal) is primed and humming right along, but no pressure reading. I sure do hope it's a malfunctioning gauge because I'd hate to think of what else might be wrong with the pool.

 

[Melt In The Sun]

Bad gauge.

 

[RaginCajun]

Broken pipe repaired, pump seal replaced and priming well, and new pressure gauge. All is well. Thanks to everyone for your input. [attachment=0:137r08gh]poolsmall.jpg[/attachment:137r08gh]

 

[waste]

Glad to hear it

Now put on your dry suit and get in and enjoy that pool :lol:

 

[PoolGuyNJ]

I hate AquaGenies. They are a PITA to winterize. I doubt, if you are in La., you would worry about this though.

I suspect you fixed the suction line.

I suspect the elbow was cracked when it was back filled originally but then you had a ground shift. This may have moved the pipe enough to open the crack.

Isn't tunneling FUN? Sorta like hitting your thumb with a hammer!

Scott

PS: Heaving, in this sense btw, is the lifting action resulting from wet ground freezing and expanding. That expansion is incredibly powerful.

I saw a demonstration once where a guy tool a 2" galvanized pipe, capped and filled with water and set it in a pot of liquid nitrogen. A minute later, it was like a pipe bomb when the ice pressure froze the water.

http://www.youtube.com/watch?v=HFMJp2xaKCk

 

[bk406]

Heaving, in this sense btw, is the lifting action resulting from wet ground freezing and expanding. That expansion is incredibly powerful.

And thats why a lot of guys you black poly for pools and ittigation in New England. PVC will crack all to pieces if the ground heaves and shifts just right.