Plumbing advice re: reliability of pvc unions
 

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 return lines without issue.

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.

Thanks, will do it.

With correct primer and glue you shouldn't have any problems at all.

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.

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.

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.

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.