Pump output leaking at the threads

[thomaskuhn]

Back story :
Back in 2011 i had solar installed for the pool. Due to inexperience and extra water going to the solar, there were times when the pump would start running dry and i would only catch it once i got home from work. At about the same time a leak started forming at the threaded pump output. I had the solar company come out and fix the issue, but they said that it was starting to leak because, When the pump runs dry, the area heats up and weakens the threaded joint. After a second and final repair, they termed it a "last ditch effort" ( seen in the pics) they were no longer covering the repair. For the repair they put in the dark grey threaded pipe which prior to this was a standard threaded pvc adapter.

Currently:
The joint is currently leaking a small stream of water. I can lose a few inches of water a month which does not allow for the skimmer and vacuum. I finally want to get around to trying to fix this. What would be some simple things to try before getting into more expensive options? What are the more expensive options? I just replaced the motor within the last year or two, so would a housing replacement be next up? I read about someone using galvanized iron pipe for this, but i am not sure how well that would work due to corrosion. What mating options do i have if the outlet pipe will need to be permanently attached to the pump housing?

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[Texas Splash]

Thomas, if I understand the background, the only issue right now (confirmed) is the leak where the threaded pipe enters the top of the pump outlet (pressure side) - correct? While you have had issues of the pump running dry in the past, the pump itself seems to be fine, it's only the connection between the pipe and pump. With pressure coming-out of the pump, there's no way an external wrap-around silicone, RTV, or other type of adhesive temp-fix is going to stand-up to the force of water coming out.

So if that's the case, then simply replacing that fitting/union to the pump and attaching a new piece of PVC should be the prescription. Others may contribute some options as well, but that's how I currently read it. But it would be helpful to know the exact details of your equipment. So please add your pool info to your signature by going to the top of the TFP web page (just under the Pool School button) and select "SETTINGS". On the next page look to the left for a menu bar that says, “MY SETTINGS” and go to "EDIT SIGNATURE" to enter your pool and equipment info there. It will help us later. This link may also help you: Pool School - Read This BEFORE You Post.

Hopefully we can help you get this resolved quickly and at a DIY-paced cost. Have a nice evening.

 

[JamesW]

If the output is leaking, then the suction side is probably leaking, too. I would suggest replacing both with high temp unions such as these.

High-Temp Union - CMP

These are less sensitive to heat from running dry.

 

[satpoolman]

If the output is leaking, then the suction side is probably leaking, too. I would suggest replacing both with high temp unions such as these.

High-Temp Union - CMP

These are less sensitive to heat from running dry.

Those unions are the only way to go - highly recommended.

 

[cowboycasey]

That is exactly what I used on all my fittings to the pump and through wall... They are great.... A pain to get them tight all the way to the seal but once sealed they don't leak...

 

[thomaskuhn]

So it sounds like I should get two union fittings (CMP) and put one on the inlet and outlet? From there just replumb the mate for the other half of the true union?

 

[Texas Splash]

That's about it. Let us know if you have any more questions though. Good luck.

 

[cowboycasey]

that is correct, just found a photo from when I was installing everything and you can see both..

The only place I found online to buy
CMP 1.5 in. MIP x 2 in. PVC Hi-Temp Union 21063-160-000- Nipples Unions Tools - 21063-160-00- Pool Products- MyPoolYard.com

what they look like close up

 

[jmastron]

Your local pool store probably carries these also if you want them faster -- I got mine for $5-$10 more than online.

And yes, these are absolutely the way to go. It's not just for the ease of disconnecting later; these unions have an O-ring at the base of the threads (in addition to the O-ring inside the union) that will make a much better seal against the pump than any kind of thread tape or dope will be able to do.

 

[thomaskuhn]

Thanks everyone. I was about to order and was going to ask about the MIP thread size on the pump, but CowboyCasey helped out there! Thanks again!!

 

[gtemkin]

Because the boss on your pump has previous attempted repairs with RTV and possibly some solvent weld product (blue) and because the new fitting's o-ring requires a flat surface to seal properly, I suggest you clean the boss very well. Use a cheap plastic putty spatula so you don't cut into and gouge the boss. Oring's don't work well if there's cuts or grooves in the surface.

 

[thomaskuhn]

Thanks everyone! The blue substance is some sort of silicone based sealant. Its luckily not rain or shine pvc glue. I like the price of the high temp union fittings so i think i will install a third one on the inlet of the filter. I have a hayward c900. I am just not sure of the thread size. It looks bigger than pump. I think they might be 2" but i can not see the threads themselves. The pvc adapter markings are on the bottom so i can not read them. Any idea what the thread size is? It looks like they make a 1.5" and a 2".

I checked the pvc fitting using a mirror and flashlight - nibco 5466?