Fittings bottom-out in pump - now what?

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chumbley

chumbley

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Jun 6, 2007
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Doylestown, PA
Background: I have an in ground pool and spa system, about 10 years old. The pump, a PacFab Challenger High Head 2.5hp unit, sits 5 or 6 feet above the pool level due to the slope of the backyard. It has always been a little fussy, because everything has to be just right to get it to pull a vacuum on the suction side, especially from the pool (the hot tub sits several feet higher than the pool). I have a check valve on the pool suction side near the pump, and that helps some, but not a lot.

Problem: Over the years, I've re-sealed the fittings on the pump (filter inlet and pump outlet) several times, and have replaced the fittings once or twice. They have never fit properly (snugly), and I've always had to use a huge amount of teflon tape to get them to seal. They just bottom out in the threads. If I get them to seal, eventually they work loose again. I've tried pipe dope, that didn't work either. I've tried o-rings on the fittings, no dice.

What's next - JB Weld? :-D

I seem to recall testing a new fitting on a new filter housing in a pool store last year, and it fit nearly bottomed out as well. Is this a known problem with the PacFab pump system? If so, any suggestions on a pump that is really good a pulling a vacuum, can run a spa and clean a 20k gallon pool?

Thanks - I'm at my wits end.

Jeff
 
Pipe fittings are tapered. You my be able to sand of a 1/16 or 1/8" of the small end of the male fitting and have it tighten without bottoming out. That presumes that there is enough thread length on the fittings to not "run out" of threads.
 
Thanks for the suggestion Ohm_Boy. Unfortunately, the problem isn't that the fittings are hitting bottom in the pump, but rather that the fittings are running out of threads before they actually get tight. The shoulders on the fitting butt right up to the pump (of course, not in a way to make them seal, that would be too easy).
 
I'd give the pipe dope another try. I can't envision a threaded connection it couldn't seal. Make sure you get the stuff for plastic pipe.

Another option is to use Schedule 80 fittings. I've never used them, but I've seen others post that the quality of the threads is better, which may make for a tighter seal.
 
Jeff,

Something's not right. I can never recall a pvc fitting that came anywhere close to bottoming out.

If you are using "hugh amounts" of teflon (a bad idea) and pipe dope and o-rings, I would suspect the pipe size is incorrect or you have a cracked pump housing.

Do you have a pic you can post of your setup? It's difficult for me to picture the wrong pipe size being used but it's equally difficult for me to envision the sloppy fit you are describing if everything is sized properly.

Waste or Sphisex may have some insight and far more experience with pvc than I, but I just cant imagine a fit that badly.

Have you inspected both sides of the fittings carefully for cracks? Too much teflon tape will crack the pump housing or possibly even the pipe.
 
When they come loose is the pvc adapter melted or warped looking? I'd imagine the housing threads are at least stripped if not cracked. Older Challengers get a little brittle over time. I've had to replace a few housings because of cracked drain threads in the volute housing.

You could try using some silicone sealant but even if it worked you'd still just be putting off the inevitable. Replace the strainer.
 
John: The pipe dope I used was Oatey Great White. Do you have another recommendation?

Dave: "Something's not right" For sure! While I'm no plumber, I've done my share of work with various kinds of pipe over the years, and I've never seen this before. With clean threads, the fitting literally wobbles in the threads slightly until the shoulders hit. In my (limited) experience, clean (no compound or teflon) threaded pipe fittings should get hand tight with at least a few threads still showing. It has to be the correct pipe size, as the jump between sizes is just too much to make that mistake (though I suspect I've made just about every mistake there is to be made at one time or another).

It is possible that I have cracked the housing at some point, but I don't see any obvious signs of that. I will get things cleaned up and inspect it well, and take some pictures if I get home early enough tonight.

Thanks to everyone for their suggestions thus far!

Jeff
 
Yes, that is the conclusion (cracked housing) that I'm coming to as well...

If I replace the pump housing (pressure side fitting) and filter pot (suction side fitting), plus the o-rings, I'm probably looking at close to $300. That's not a problem, but does it make sense to put $300 into a 10 year old pump? Or should I just opt for a completely new pump? If so, which one?

Thanks again...

Jeff
 
Can you get an adapter to epoxy into the pump housing, and then thread your pipe into that? My brother had a similar problem, pump with shipping damaged threads, but he neede to do from 2" to 1.5" anyway, so he epoxied a bushing in, works fine. Good Luck!
 

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chumbley said:
I thought about that - but don't know of a 2" MPT to 2" FPT fitting. So I would need to do 2" MPT to 2" Slip then 2" Slip to 2" FPT. Could be done, but I would need to rework all of my plumbing to get it to fit.
Click to expand...

I think you're overthinking the way to do this. If you want to try epoxying the MPT in, it may solve your problem - you don't need to reduce it and rethread into it. You only get 1 chance at this way to fix the probable problem. But if the other option is to replace the whole pump housing, why not give it a try?

How are you able to keep rethreading the existing MPT, a union? If you have enough room to add a coupling in there, you can use a new MPT (M/A - "male adapter") and use a coupling to add in a new stub of pipe.

If what I've just said is unclear, I'll give it another try (a pic would sure help though :) )
 
Update:

After picking up a couple different kinds of epoxy, and new nipples and unions, I cleaned everything up and inspected closely for cracks. I could find none. I tried the new nipples, and surprisingly, they seemed to fit properly! I say surprisingly, because I have replaced the nipples before (a couple of times in the past years) and they never fit this well.

In any event, it is all back together with clean threads, new nipples, and a couple wraps of teflon tape. We'll see how it goes - because in the past - when I thought I had it fixed I would go out a few weeks later and find the fittings were loose again. If they are - off comes the teflon and on goes the epoxy!

Thanks gang.
Jeff
 
One other thought that I should have mentioned in my first post here:

If the new fitting succumbs to the same issue, try the 'triple threat':

1) Extra couple of wraps of teflon tape

2) Pipe dope (permatex or similar)

AND

3) Put an o-ring on the male adapter so that when the threads bottom out, you've got the o-ring to keep the seal.

If the 'triple threat' fails - it's time for a new housing or entire pump :(
 
Well, it took two days for the problems to reappear. The suction side wouldn't pick up easily and the pressure side started leaking. Stick me with a fork, I'm done. I took it apart, cleaned it, packed the threads with EP-400 and reassembled. If it happens again, it's either new housings or new pump time.

Jeff
 
I have the same type of pump in the 1hp model and noticed the fittings bottom out also. My pump has always had problems with the 2" fittings and I've tried numerous ways to get it to stop leaking (or taking in air). I ended up replacing the pump with a new one of the same type and have the same problem. When looking at the threads on the pump it looks like there is a significant taper where the fittings don't touch the sides of the threads until near the bottom of the thread. I looked at both pumps (old and new) and found this is common on both the pumps. Does anyone know if the PacFab Challenger pumps are made with the tapered threads? I plan to buy a new pump but wont buy another challenger if they are made with tapered threads as I cant get a good long term seal using sch 40, sch 80 and tons of tape/dope/silicon.
 

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