I opened my pool this past weekend and could not get the pump to catch prime. It gets about 90% there, but the last air bubbles never clear. I put a hose over a few places to find the air leak and have isolated it to the union on the suction side that meets the pump housing. I'm hoping it is just a bad gasket or O ring, but I cannot get the union nut off. I tried a strap wrench and end up breaking the rubber strap with the force I had to put on it. I moved on to using these slip joint pliers, which get a great grip on the nut, but I still cannot get it to budge. Any thoughts on how I can break it loose? I'm starting to wonder if it got cemeted in place.
Stuck Union Nut Connected to Pump Housing
- Thread starter pinballmik
- Start date
- Jul 21, 2013
- 54,789
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
- Jul 21, 2013
- 54,789
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Hammer and chisel, have had to do it. Then new plumbing, most likely.
Even with new O ring, etc. there will probably continue to be some air in that pot as the suction plumbing is above the pump inlet.
Also, no mention was made of lubricating the pump-lid gasket.
For hammer and chisel, is the idea to smash the union nut all together? Or use them to spin the nut free? I've tried hammering a flat head down on the ridges, but no luck. If I'm breaking the nut, would I be able to avoid re-plumbing it using a split nut?
Sorry, I did forget to mention the lid gasket. I greased it with silicone lube to start hoping it would be a quick win. With the plumbers putty there, the pump gets fully primed with just a few tiny bubbles, so it is looking like that union is the culprit.
Sorry, I did forget to mention the lid gasket. I greased it with silicone lube to start hoping it would be a quick win. With the plumbers putty there, the pump gets fully primed with just a few tiny bubbles, so it is looking like that union is the culprit.
Attachments
frbruno64
Bronze Supporter
You will need new plumbing one way or the other. So, how about cutting the input lines before the elbows to allow you the ability to unscrew the entire union from the input side of the basket. Then install a new union an re-plumb as necessary.
Lake Placid
In The Industry
- May 27, 2021
- 727
- Pool Size
- 17000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Since the union is the likely culprit, spin it off by and means necessary. Big channel locks, large pipe wrench, cut a couple grooves in it with a Dremel and peel it off, hammer and chisel, whatever it takes. You can cut the stub of pipe nearest the downward 90 closest to the pump (red line in the pic) add a fitting extender and rebuild the plumbing pretty close to as is.
frbruno64
Bronze Supporter
sktn77a
Gold Supporter
Did you inherit the pool (and the house)? If so, the previous owner may have cemented it, but that's not the most likely scenario. Get a can of spinach and then try again with the adjustable wrench!!!
@1poolman1 - just out of interest, why would suction plumbing above the pump cause bubbles?
@1poolman1 - just out of interest, why would suction plumbing above the pump cause bubbles?
Lake Placid
In The Industry
- May 27, 2021
- 727
- Pool Size
- 17000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Any air able to get in to the suction side will cause bubbles. Location doesn’t matter, the pump pulls a vacuum and air is easier to draw than water, so the air manifests itself in the pump basket.
According to the Sta-Rite pool hydraulics classes I took many years ago (and the physics of water flow haven't changed) when the plumbing to the inlet of the pump is above the the pump itself the extra work the pump has to do to overcome that extra lift will exacerbate any even very-tiny possible air leak that may otherwise not cause air in the system. And the bubbles may not have to be from a suction leak at all but a form of cavitation happening in that loop. They had all the math formulas laid out, but all I cared about was the practical aspects (and it was over 30 years ago), don't plumb the pump with the inlet plumbing higher than the pump inlet or you could get air into the system.
Thanks all. I appreciate the help on this. Planning to go ahead and cut it before the two nineties as mentioned and do whatever I can to separate the union from the housing. Working with PVC is new to me, so thanks Lake Placid for the call out on the extender. I was thinking I'd have to get a large piece of straight pipe and cut it down. Good to know I can go with that instead. If I get really crazy, I may try to build up the pad the pump is on and cut down the outlet side so it is a straight shot on the suction side getting rid of the drop down poolman mentioned.
The whole setup was inherited from the previous owner.
The whole setup was inherited from the previous owner.
Cut and have the plumbing in reverse. Come down from the diverter valve to whatever it takes to come straight into the suction union.