Plumbing question about Unions

[Mickey]

Short version: Should I put some rectorseal or silicone (NOT aquarium silicone, but the sticky stuff you use on gaskets, etc) on union threads to ensure they can be loosened and tightened over time?

Longer version: My tank has been up for 19 years last month (200+ gallons). At the time I was totally new to doing my own plumbing and I used unions initially beneath the bulkheads, then went back and added ball valves below the unions. (I know, I know.....higher quality true union ball valves was the right way to do it, but setting up this tank was costing so much I didn't think it would matter if I used some stuff from Home Depot or Lowes ). Anyway, I've got my chiller plumbed on a closed loop with the bulkhead coming from the middle of the tank then down through the floor. Today I was shutting the chiller down as I'm making some changes and wanted to shut off the water coming from the tank to the chiller so I could disconnect it all. You guessed it - the ball valve was frozen and I couldn't budge it. In trying to apply enough pressure to close it, the union loosened and water started pouring down. I couldn't get a grip on the union to tighten it with all the water. All I could envision was 100 gallons pouring through the floor to my basement. The awkward position of being on my hands and knees halfway inside the stand didn't help. Eventually I got it using a strap wrench. I'm planning to replace the ball valve with a true union one but I can't replace the existing union as it is right up again the bulkhead. So I want to be sure that in the future that union is easy to open and close.

Sorry for the wordy post. I'm still calming down from my near disaster.

Any new reefkeepers out there reading this, remember this lesson. Don't skimp on the plumbing and buy the good quality ball valves, and periodically open and close them.

Mickey

 

[BeanAnimal]

Silicone grease will not harm union threads, though I have never had one seize. In fact, I recently had one that was part of a true union valve leak due to years of slight pump movement and it likely working loose.

 

[Mickey]

I don't know if it was seized or if it was just tight or stiff. I just could get it to turn by hand though it did tighten once I put a strap wrench on it. I suppose when I set the tank up many years ago I might have tightened it more than it needed to be, or it was just so wet with water pouring over it I couldn't get a good enough grip, (or I'm just not as strong as I used to be!.

 

[jimk60]

Teflon paste is safe to use as well as food grade anti seize. I would still use either sparingly.

 

[JayM]

Maybe try a wrap or two of Teflon tape?

 

[Mickey]

Thanks.

I have read several places that you shouldn't use teflon tape on unions.

 

[BeanAnimal]

Thanks.

I have read several places that you shouldn't use teflon tape on unions.

I think that is in the context that it will do nothing to help them seal. I suppose too much could cause the union to not seat fully as well. The silicone grease is likely the least messy. PTFE paste is a bit more of a mess, but would work the same.

 

[mfinn]

Since I heard about the paste stick specifically for pvc, I use it on all threaded pvc fittings.
I had to break apart a couple unions last month that had been in use for 7 years, and had zero issues getting them apart.

 

[JayM]

Thanks.

I have read several places that you shouldn't use teflon tape on unions.

That’s correct if it’s being used as a sealant. I was thinking more a barrier to keep the threads from binding up on each other.

A grease will definitely work better, but tape will be less messy.

 

[Black Dog Reefing]

I personally have used gasket grease on my fittings and have had no issues. Most all plumbing supplies come in a food grade version (I am a maintenance/ pipe welder in a food plant so I have a fair bit of experience with these products). I haven’t had anything freeze on my tank yet, but at work when working on decades old piping, just some light tapping with a hammer (would recommend a dead blow or anything plastic as to not crack or scar the fittings) usually does the trick on unions. As for the valves, I really wanted to do gate valves but it seems the schedule 40 pvc gate valves (red handle) I’ve always used in the past have been discontinued. I had to settle for some true union ball valves, lowe’s sells them (attached picture) and they aren’t too much more than the basic slip/slip ones I assume you currently have. They appear to be a higher quality with better tolerances and they close/ open much smoother than the cheaper alternatives.

 

[BeanAnimal]

FWIW - the lowes true unions are serviceable - but nowhere near the quality of hayward, spears, etc. There is certainly a price difference though.

 

[Black Dog Reefing]

FWIW - the lowes true unions are serviceable - but nowhere near the quality of hayward, spears, etc. There is certainly a price difference though.

Agreed, it really came down to the convenience factor for me and the timeline I had to get the plumbing done. We only use spear at work and would absolutely go that route if possible

 

[BeanAnimal]

I have do have a few of the lowes ones in the system, some of them 10+ years old.. They are stiff but still work. The 10 year old spears moves like butter still.

 

[BeanAnimal]

I think the lowes brand I have is American Valve - not sure who they source from now.

 

[Black Dog Reefing]

I think the lowes brand I have is American Valve - not sure who they source from now.

The true union ones I went with are Reliabilt. Not sure the source on those but I have been happy with them so far. Can tell they’re definitely not a gate valve though

 

[QuickrdenU]

I don’t see a point. Though the cheap ones from hardware stores are far more sticky(threads harder to remove). But then again, the cheap valved unions stick so much(the actual valves) that I don’t think I would ever choose to use them somewhere critical like inside my home.

Go with nice plumbing parts and don’t use any grease or tape. You just don’t need it.

 

[BeanAnimal]

I don’t see a point. Though the cheap ones from hardware stores are far more sticky(threads harder to remove). But then again, the cheap valved unions stick so much(the actual valves) that I don’t think I would ever choose to use them somewhere critical like inside my home.

Go with nice plumbing parts and don’t use any grease or tape. You just don’t need it.

I tend to lubricate nice parts too. Never seize on break parts, manifolds, etc. and silicone gasket lube on gaskets.

 

[Mickey]

Thanks for all the comments. Very interesting to read. I did use the red handled ones from either Lowes or Home Depot and as I said earlier they've been on the system for 19+ years. I was not very diligent about opening or closing them periodically which is probably the issue. The valve I had tried to close I did try tapping with a hammer. Unfortunately that twisted the pipe just enough to loosen the union at the bulkhead (the valve is right below that union) and water started pouring down, then I had trouble closing the union to stop the flow. Luckily I knew where my strap wrench was and it took only a minute or so to get it and then get the valve shut, otherwise I could have lost 100 gallons into my basement. Hubby would not have been pleased.

Since I heard about the paste stick specifically for pvc, I use it on all threaded pvc fittings.
I had to break apart a couple unions last month that had been in use for 7 years, and had zero issues getting them apart.

Which paste are you referring to? Can you send a picture?

 

[mfinn]

Thanks for all the comments. Very interesting to read. I did use the red handled ones from either Lowes or Home Depot and as I said earlier they've been on the system for 19+ years. I was not very diligent about opening or closing them periodically which is probably the issue. The valve I had tried to close I did try tapping with a hammer. Unfortunately that twisted the pipe just enough to loosen the union at the bulkhead (the valve is right below that union) and water started pouring down, then I had trouble closing the union to stop the flow. Luckily I knew where my strap wrench was and it took only a minute or so to get it and then get the valve shut, otherwise I could have lost 100 gallons into my basement. Hubby would not have been pleased.


Which paste are you referring to? Can you send a picture?