PVC union size differences

chrisexv6

Well-known member
Feb 8, 2008
340
Milford, CT
Going to plumb in my new AutoPilot this weekend but I wanted to add unions on either side of the manifold for easy removal (winterizing, etc)

I picked up a couple 2" unions from Lowes, but these things are physically huge. Ive seen other 2" PVC unions on the net that are much smaller, dimension wise.

Is there any difference between the really chunky ones at Lowes and smaller ones I find on the net? Is there really a reason to have these ugly looking things vs the nicer "lower profile" (I guess you could call them) versions?

What I bought: http://www.lowes.com/pd_188234-34146-P240S+2_0__?productId=3352016&Ntt=american+valve+pvc+union&pl=1&currentURL=/pl__0__s?Ntt=american+valve+pvc+union&facetInfo=

I checked the dimensions on it, vs from other brands and it is literally 1" larger in diameter and about 3/4" longer than the others.

What have other people used? I know AutoPilot sells their own union kits, but they dont specify the actual dimensions of the fittings.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
The cell has it's own built-in unions, so you can remove the cell for the winter without adding any unions of your own. There is nothing in the manifold that gets glued in that is any more sensitive to freezing than any of the rest of your plumbing.

The larger unions are usually easier to tighten and loosen as you have more to grab onto, but otherwise have nothing to recommend them. Most of the mail order unions are better.
 

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
23,646
SouthWest Alabama
Those unions are schedule 40 rated and most likely the one's you're comparing them too aren't. Either would probably work at pool pressures but I like the sch 40 fittings and pipe.
 

chrisexv6

Well-known member
Feb 8, 2008
340
Milford, CT
JasonLion said:
The cell has it's own built-in unions, so you can remove the cell for the winter without adding any unions of your own. There is nothing in the manifold that gets glued in that is any more sensitive to freezing than any of the rest of your plumbing.

The larger unions are usually easier to tighten and loosen as you have more to grab onto, but otherwise have nothing to recommend them. Most of the mail order unions are better.
Actually I had another secret plan :) I basically want to make "inserts" that will go in place of the manifold itself, so if the AutoPilot goes down I can just swap in another insert. One will have my tab feeder plumbed in, the other will have a barb fitting that will feed my liquidator. So basically I have 3 ways of chlorinating (using only one at a time, of course) if something goes wrong.

I went to my go-to place for good quality stuff, McMaster.com, and they show fittings that look just like the American Valve one from Lowes.

As far as Sched 40 vs not, I was looking at reputable companies (American Valve makes the one from Lowes, King Brothers Co and Spears make the lower profile ones...all look to be reputable made in USA plumbing manufacturers), and they were all showing the pressure rating of 150psi@73F which seems to be par for the course on a PVC union.