SWG unions

[Fuldo]

While thinking about my upcoming installation of a Circupool RJ-30 system and what items I should have on-hand for the replumbing I started to wonder about something.

It appears that all SWG systems come with plastic unions that mate with the chlorine generator body. Are these unions special in some way or will the SWG bodies mate properly with standard commercial PVC unions? For that matter, are special unions usually used for all pool applications perhaps because of enhanced chlorine resistance or are standard PVC unions such as what can be bought at Lowes typically used for pool applications?

 

[ctrav]

i would be hard pressed to believe that the unions are anything special other than the fit. Perhaps a quick call to a pool company or the manufacturer will give better insight...

 

[JoyfulNoise]

Some of the manufacturers, like Pentair, use non-standard thread pitches on their unions. So you should use the unions that come with your SWG. I know for a fact that you cannot use standard SCH40 PVC unions with a Pentair SWG. The material it is constructed from might be ABS or CPVC but it really doesn't matter as both of those materials, as well as standard PVC, hold up well against chlorinated pool water.

 

[PoolguyinCT]

Equipment has lower thread count buttress or v threads than a piping supplier stock.

They are not proprietary, just different than npt.

this makes disassembly and service quick and practical, particularly when there is limited room.

 

[Fuldo]

Thanks for the insights. Sorry for asking about such minor details but my engineering background makes me feel vulnerable if I don't fully understand all equipment I must deal with. I guess it comes with the territory.

After researching a little further I talked to someone at discount salt pool and he confirmed that the CircuPool unions are indeed unique and incompatible with standard PVC unions or other SWG brands. The part of the union that is cemented to the pipe is unique, has a certain o-ring and a replacement is available from them. I suspect it's a standard commercial o-ring but likely not the same size as used on other brands/models. The chances of the plastic union parts going bad or getting damaged is rather unlikely and probably not worth having any spares on-hand. However, I'll likely buy some replacement o-rings to have on-hand based on my experience with other o-rings used in my pool equipment.

 

[JoyfulNoise]

Thanks for the insights. Sorry for asking about such minor details but my engineering background makes me feel vulnerable if I don't fully understand all equipment I must deal with. I guess it comes with the territory.

After researching a little further I talked to someone at discount salt pool and he confirmed that the CircuPool unions are indeed unique and incompatible with standard PVC unions or other SWG brands. The part of the union that is cemented to the pipe is unique, has a certain o-ring and a replacement is available from them. I suspect it's a standard commercial o-ring but likely not the same size as used on other brands/models. The chances of the plastic union parts going bad or getting damaged is rather unlikely and probably not worth having any spares on-hand. However, I'll likely buy some replacement o-rings to have on-hand based on my experience with other o-rings used in my pool equipment.

My unions and o-rings are going on 6 seasons old.....no leaks yet (knock on wood)....

 

[Fuldo]

I installed my RJ-30 system on Sunday. Before installation I inspected and measured the o-rings hoping to discover it was a standard commercial part. It appears to be of 4 mm round cross-section and 60-61 mm ID. That's actually a standard metric size. However, the o-ring is clear and seems softer than typical commercial o-rings. I've dealt with o-rings in product design for decades and have never seen a clear o-ring. It turns-out that Parker o-ring manual (considered the bible of the industry) doesn't even show a clear compound available. This seems like a custom part of unusual material. The other thing I found is that the groove for the o-ring in the CircuPool coupling is very non-standard. It's much narrower and shallower than what o-ring manufacturers specify. The groove measured 3.5 mm wide by 2.49 mm deep. The groove is actually half a mm (20 mils) narrower than the o-ring diameter. That plus the groove being shallower than normal doesn't allow the ring to be manually placed into the groove before assembly as normal practice. This requires the installer to place the o-ring between the two coupling faces, center the o-ring over the groove and then tighten the coupling to drive the o-ring into place. The seal should be very forgiving considering how much the o-ring is compressed, much more forgiving than a standard commercial fit. I had a small amount a misalignment but even with my very short run the joints sealed perfectly. I lubricated one o-ring with silicone spray (I didn't have any silicone grease) but wiped it off after it was too difficult to handle the lubricated o-ring during placement. The other o-ring I placed dry. No lubricant was provided with the SWG system and no mention in the installation instructions about lubricating the o-rings; something that's considered standard/essential practice.

I realize this is more technical information than most people would care for but thought it may be of interest and benefit to some.

 

[JoyfulNoise]

Silicone elastomers can be transparent. In fact, silicone is, by nature, transparent/translucent but is usually dyed to make it a specific color. There are all types of silicone elastomers and silicone/urethane materials. They are generally used in specialty chemical handling circumstances and would be totally overkill for a pool water sealing application. A regular standard rubber o-ring with an appropriate amount of silicone (no Teflon please) grease would suffice.

 

[Saturn94]

My unions and o-rings are going on 6 seasons old.....no leaks yet (knock on wood)....

After 14 years I replaced just the O rings, but only because the original ones were flattened slightly; they weren’t leaking yet but figured it was a good idea after all these years.

 

[PoolGate]

There is little chance of you being able to mate your proprietary unions that came with the SWCG with stuff you get at Home Depot. You could try to get a couple from the SWCG maker but for Jandy at least, I tried and had no luck at all. If you want you could add another union before and after the proprietary one to allow you to remove the SWCG and replace with a straight pipe (for winterizing or other reasons).