View Full Version : Plumbing advice re: reliability of pvc unions
trilinearmipmap
01-12-2014, 03:53 AM
I'm going to re-plumb my tank after many years. I wanted to know people's experience with unions.
So far I have only had unions on drain lines which are over the sump, in case of a leak it would drip into the sump. None have leaked though.
I am looking at adding a couple of unions to the return line for ease of access, and these would be in the back of the tank. A leak would be a minor disaster.
Just wondering if people have experience on leaking or non-leaking of return lines which are under pressure.
Proteus
01-12-2014, 03:56 AM
I have unions on return lines without issue.
The Grizz
01-12-2014, 04:03 AM
Same here, always have unions on returns and never an issue. I use an o ring grease to make sure they don't dry out and seal tight.
trilinearmipmap
01-12-2014, 05:21 AM
Thanks, will do it.
Madreefer
01-12-2014, 05:49 AM
With correct primer and glue you shouldn't have any problems at all.
craigwmiller
01-12-2014, 05:58 AM
Some have a flashing of plastic on the non-o-ring side of the union left over from the molding process... I use some 600 grit then 1500 grit sand paper to smooth it down. Saves the o-ring from distress.
The Guy
01-12-2014, 07:09 AM
I'm going to re-plumb my tank after many years. I wanted to know people's experience with unions.
So far I have only had unions on drain lines which are over the sump, in case of a leak it would drip into the sump. None have leaked though.
I am looking at adding a couple of unions to the return line for ease of access, and these would be in the back of the tank. A leak would be a minor disaster.
Just wondering if people have experience on leaking or non-leaking of return lines which are under pressure.
I have unions on my return PVC piping to be able to take my check valve out for cleaning and it's never been a problem, just don't over tighten them. Do up hand tight then 1/8- 1/4 turn more with channel lock pliers.
O-rings will deform. No problem leaking if left alone but if in a few years you take things apart might nice to have new ones available for when you re-assemble.
Last time cleaned CL pump noticed them rather flat, not leaking but took measurements to have next time.
Madreefer
01-12-2014, 02:33 PM
I have unions on my return PVC piping to be able to take my check valve out for cleaning and it's never been a problem, just don't over tighten them. Do up hand tight then 1/8- 1/4 turn more with channel lock pliers.
That's how I tightened one a long time ago and I broke the bond where it was glued on. But I did'nt use primer. As for the o-ring seal i've never had a problem. It's actually a good idea to use unions on external return pumps in case your pump or pump seal goes, much easier than having to cut your plumbing.
1eyedjyde
01-12-2014, 05:16 PM
its always a good plan to use unions around the wear items on your plumbing ie pumps, check valves, wave devices. It makes maintenance possible without having to dismantle your plumbing.
asylumdown
01-12-2014, 05:24 PM
its always a good plan to use unions around the wear items on your plumbing ie pumps, check valves, wave devices. It makes maintenance possible without having to dismantle your plumbing.
+1, my pump would be unserviceable without them. The only problem I have had has been some slow salt creep around where the union joined the flex tube piping. I solved that by smothering the seam in aquarium silicone. I'll never be able to get half the union off the pipe, but all I really care about is being able to get the pump out for cleaning.
The Guy
01-12-2014, 06:54 PM
That's how I tightened one a long time ago and I broke the bond where it was glued on. But I did'nt use primer. As for the o-ring seal i've never had a problem. It's actually a good idea to use unions on external return pumps in case your pump or pump seal goes, much easier than having to cut your plumbing.
I guess me being an HVAC mechanic by trade I forget and assume people would use a hold back on the stationary glued part of the union, also some O-ring lube is good idea on unions.
Hey Bill your new DT looks awesome! :lol:
Madreefer
01-13-2014, 01:11 AM
I guess me being an HVAC mechanic by trade I forget and assume people would use a hold back on the stationary glued part of the union, also some O-ring lube is good idea on unions.
Hey Bill your new DT looks awesome! :lol:
Hey thanks bud.
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