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View Full Version : PVC Union Compatibilty Question (Help PVC Experts!)

grim
02/06/2004, 01:14 PM
I've got a beckett injector that was built with a set of spears unions at the top and bottom to connect to the plumbing (MTC HSA).

I need to change the input plumbing to use an external pump, and therefore, need to change the input plumbing a bit to extend the hose inlet. None of my local suppliers have 'spears' 3/4 unions. I'd like to just use another union to connect to my existing half union.

Any ideas if unions are compatible between companies? Do I need another spears union to be able to go attach to this? I'd prefer not having to hack up my existing plumbing if I didn't have to. The way the plumbing is now, I'd need to make some bends in the hose to get it to my pump, I'd rather not do it.

So, PVC gurus, are unions generally compatible?

jb
Cheapreef
02/06/2004, 01:41 PM
They sould all be a standard pipe thread.(ntp)

Clinton
Highlander
02/06/2004, 02:09 PM
The diameters of the two halves are not always compatable. I have run into this problem when HD decides to change suppliers and I need to exchange one half of a coupling for an upgrade, etc.
Acrylics
02/06/2004, 02:46 PM
Originally posted by grim
Any ideas if unions are compatible between companies? Do I need another spears union to be able to go attach to this? I'd prefer not having to hack up my existing plumbing if I didn't have to. The way the plumbing is now, I'd need to make some bends in the hose to get it to my pump, I'd rather not do it.

... are unions generally compatible?

Usually not, IME, most companies choose to use their own thread pattern or diameter (as highlander points out) for the lock ring. But sometimes they are compatible (rare though), hate to say it that way but...

James
grim
02/06/2004, 03:35 PM
Yeah, that is what I figured.. Maybe I can find the proper spears fittings online..

jb
AZDesertRat
02/06/2004, 08:57 PM
Most all reputable plumbing supply or sprinkler supply warehouses sell Spears fittings. Try contacting Spears on the web and getting the name of a local supplier. I have run into the same thing and different brands are definitely different threads and diameters.