Screw / quick connects and/or unions?

[gmason86]

Hi,

I'm hopeful this is a really simple question, but I can't quite find an answer to it. I did ask it as part of a separate thread about a whole re-plumbing job, but I think it got lost!

When plumbing things like pump and filter, I'm intending to use the quick connects (the screw things where you screw the pipe onto the pump, etc. rather than gluing it - is that what they're called???) at the point where the piping actually connects to the pump, filter, etc.

However, I've also seen people use unions before/after the equipment. e.g. a union may be added in between the pump and filter, and before the pump itself, etc.


Can someone explain the purpose of the union if you already have the quick connect (or whatever it's called) at the actual connection point to the piece of equipment? If you need to do maintenance (e.g. cleaning filter, winterizing, etc.), don't the quick connects allow you the exact same access as the union? Or is there a benefit to having both?


I'm getting a new filter/pump installed today (in a few hours), so I'm hoping someone can clear this up for me before then so I can do the right thing I realize I could simply cut the pipe and install a union later if I don't hear in time, but I'd rather do it right first time


Thanks again,

Graham.

 

[kellyfair]

If I’m not mistaken, people install unions so that they can pull things apart later if something goes wrong without having to cut the pipe.

 

[Richard320]

A union allows you to seperate the plumbing without having to start sawing. Some equipment comes with integral unions. Be careful with them -- they generally use proprietary threads so don't cross-thread them.

 

[PoolGate]

Most pumps have proprietary threads and sizes. By also using a standardized union, you could remove the pump and install a bypass pipe, for instance if you winterize and want to bring your pump in the house. But strictly it is not necessary. Mine does not have separate unions only what the equipment manufacturer provides. In the same respect, if you ever want to replace a pump with one from a different maker, you would not have to cut the plumbing back only install a new short piece connect to the standard union on one side and the proprietary pump end on the other.

 

[gmason86]

Thanks everyone for the quick and informative replies!


So from what I now understand, if my pump (new one going in and any future ones) used standard size threading, then there would be no benefit for also adding a union? That's because I can disconnect equipment, replace it, do whatever I want basically because it is all standard.

But on the assumption that either my new one going in (Pentair Superflo VS) or any future one used a proprietary size, then there would be benefits to adding a union because it is then a standard size? On that note, does anyone know if the Pentair Superflo VS uses standard size threading?

Have I understood correctly?


On that basis, with a new pump and filter going in, where would you add unions? I'm thinking in between pump and filter, before pump (although the previous owners put a ball valve there so that can obviously be unscrewed, so is one there necessary?), and after the filter?

I will be re-plumbing basically everything in my shed at some point when I get around to it (mostly everything on the return side). So if I get them to use a union after the filter, that makes it then easy to disconnect the existing pipes once I'm ready to replace them. Would that size of the union then need replaced and then attached to the new piping, or is there some way to remove the piping that would be glued onto that side of the union and then my new piping added in place? (Sorry if that's a stupid question - just not something I've done before!!).

Thanks!!

 

[sktn77a]

So from what I now understand, if my pump (new one going in and any future ones) used standard size threading, then there would be no benefit for also adding a union? That's because I can disconnect equipment, replace it, do whatever I want basically because it is all standard.

Not sure I quite get what you are describing as "quick-connects". If your pump has standard threads (not a union) and you install a threaded PVC adapter and then glue it to the PVC pipe, you have to saw through the pipe if you ever need to remove the adapter (or the pump). If you use the threaded PVC adapter and then a union, you can just unscrew the union to remove the pump. If your pump comes with union fittings, then you're all set - the threads may be proprietary but you don't have to use an additional union.

 

[gmason86]

Not sure I quite get what you are describing as "quick-connects". If your pump has standard threads (not a union) and you install a threaded PVC adapter and then glue it to the PVC pipe, you have to saw through the pipe if you ever need to remove the adapter (or the pump). If you use the threaded PVC adapter and then a union, you can just unscrew the union to remove the pump. If your pump comes with union fittings, then you're all set - the threads may be proprietary but you don't have to use an additional union.

Hmmm, then maybe I wasn't quite understanding!

I thought that if you use the threaded PVC adapter, then you can simply unscrew that and then remove the pump if desired because it isn't actually glued to the pump, but rather screwed on. Then you could screw that directly onto a new pump, if the same size of threading was used. I understand that if a new pump (or any other piece of equipment) used a different size of threading, then I'd need to saw the pipe because I couldn't then just screw the existing adapter directly onto the new one, and then use the new adapter for the new pump. But from what you're saying, it doesn't sound like that's correct.

What I really want to avoid is anything being glued directly onto the pump or filter (which is basically what I inherited when I bought this house, haha). But I also want to future-proof and make things as easy/simple as possible.

Oh and quick connects was just the word I heard someone else use. I believe what I mean is the threaded PVC adapter that basically screws on/off.

Thought I was becoming less confused, but now I think I'm becoming more confused

 

[PoolGate]

Hmmm, then maybe I wasn't quite understanding!

I thought that if you use the threaded PVC adapter, then you can simply unscrew that and then remove the pump if desired because it isn't actually glued to the pump, but rather screwed on. Then you could screw that directly onto a new pump, if the same size of threading was used. I understand that if a new pump (or any other piece of equipment) used a different size of threading, then I'd need to saw the pipe because I couldn't then just screw the existing adapter directly onto the new one, and then use the new adapter for the new pump. But from what you're saying, it doesn't sound like that's correct.

What I really want to avoid is anything being glued directly onto the pump or filter (which is basically what I inherited when I bought this house, haha). But I also want to future-proof and make things as easy/simple as possible.

Oh and quick connects was just the word I heard someone else use. I believe what I mean is the threaded PVC adapter that basically screws on/off.

Thought I was becoming less confused, but now I think I'm becoming more confused

I think you have it correct. Most pumps that I have ever seen have threaded connections (what you are calling quick-connects). Many of those are proprietary. They include the plumbing half which usually glues onto your existing plumbing. You only really need those as you will be able to remove the pump for servicing/replacement just by unscrewing the pump behind. A union is essentially the same thing. It is a "quick connect" fitting. The difference with unions is that you can go buy them anytime for about $5. Again, you don't need them and most people do not add the extra union.

 

[gmason86]

I think you have it correct. Most pumps that I have ever seen have threaded connections (what you are calling quick-connects). Many of those are proprietary. They include the plumbing half which usually glues onto your existing plumbing. You only really need those as you will be able to remove the pump for servicing/replacement just by unscrewing the pump behind. A union is essentially the same thing. It is a "quick connect" fitting. The difference with unions is that you can go buy them anytime for about $5. Again, you don't need them and most people do not add the extra union.

Oh great, that's reassuring Thank you!


So if I were to unscrew those two threaded connections in the picture, then the pipe should come straight out and I could walk away with the pump (after removing the electrical connection as well, of course!)? If so, that's really the main thing that I want to achieve!

In case you're interested, this (Amazon Drive) is what I inherited when I bought the house, haha. I definitely don't want that madness again! When I re-do everything after the filter sometime in the future when I have enough spare time, then I'll add some unions, change all the piping, etc.

Thanks again!

 

[PoolGate]

Yes, unscrewing those two would release the pump for removal.

Wow yeah that is a mess.

I posted this up for others to see.

 

[gmason86]

Yes, unscrewing those two would release the pump for removal.

Wow yeah that is a mess.

I posted this up for others to see.

Great, thank you!

And come on, no need to shame me, haha. Well, you're actually shaming whoever installed this in the first place! When the new pump and filter go in today, it'll be switched to the white PVC, and will use the threaded fittings as we've discussed. I'll then tackle what comes after the filter when I get some time. The first ball valve heads to the stairs (bypasses heater completely). The green hose goes to the slide. The second ball valve goes to the heater, and then to the main returns in the pool. You'll probably see another thread devoted to fixing this mess when I find the time, whether that's this year or another

Thanks again!

 

[todd.brock]

Whoever installed that should probably be ashamed

 

[sktn77a]

I think you have it correct. Most pumps that I have ever seen have threaded connections (what you are calling quick-connects). Many of those are proprietary. They include the plumbing half which usually glues onto your existing plumbing. You only really need those as you will be able to remove the pump for servicing/replacement just by unscrewing the pump behind. A union is essentially the same thing. It is a "quick connect" fitting. The difference with unions is that you can go buy them anytime for about $5. Again, you don't need them and most people do not add the extra union.

That's what most people call a union. If that's what the OP is going to get on his new pump, then he's good to go.