Pressure testing copper lines - need some help.

[MrEd]

Hi all.

Only about 5 days away from a first burn on my tarm solo with 500G tank install...all done by myself.

Question for today is, what is the best way to pressure test my copper lines? Is there any inexpensive devices that would allow me to seal and charge the lines without soldering and unsoldering caps on the ends...and then once I have those devices, what pressure do I put in, and for how long?

I've done a fair amount of soldering in my time, and always tested in the past by charging the lines with water and seeing what leaks occurs, but this time I'd like to be able to be more methodical, and test various runs independently and with the amount of water that will be in this system I don't want to have to fill/test/drain/repair/fill/test/drain/repair too many times....

Thanks in advance for any advice.

 

[Chief Ryan]

I do HVAC for a living and the only way i can think of is what you said you don't want to do.

You can put some water pressure in the system and try to valve off the opposite side to increase the air pressure and listen for air leaks but there is going to be some water to drain if you do have a leak.

The way it's done with a refrigeration system is there are pressure taps. We use nitrogen to pressurize through a set of gauges and we use soap bubbles on all the joints. If you want you can get a pressure tap and a tee fitting. Solder it in and use compressed air to pressurize.

Hope that helps

 

[steam man]

How ironic this post came up since I've never seen one like it. Because............I just spent a week dealing with very small leaks on my newly installed solar system. I tested to 90 psi since that is my relief setting using air. Everything else is rated much higher. Anyway, I used some commercial leak check and at times a small amount of dish soap and water in a commercial sprayer. The dish soap worked as good as the leak check. I did not have one solder leak-it was all those stinking chinese threaded fittings that gave me the problem. I even had a leak through a sand cast threaded brass test plug. If anything the threaded fittings will be your weak link. My lines had to be perfect since glycol will find its way out of anything. After filling with water to just about 60 psi, I could still find leaks I didn't see with the air. I still had a thread leak after filling with glycol. I did have valve packing drips. I am finally up and running and making hot water.

Moral of the story-buy american fittings and make sure the threaded joints are up tight-thanks for letting me rant.

I think I would just test with air to operating pressure and soap the joints. After that, fill system with water about 80 deg and watch for leaks.

Mike

 

[Dredknot]

I find wrapping the threads with teflon a couple of times then applying a thing layer of pipe dope works very well on almost all threaded fittings.

 

[EatenByLimestone]

I use pipe dope with teflon for gas and water fittings. I've never liked tape.

I never had to pressure test a water system. I've only worked on tap water systems and if it didn't show a leak it was good to go. My Grandfather had 80psi of pressure though.

With propane systems I used a match. (No, don't do that. I just wanted to get somebody going.) I charged up the system with tank pressure. Turned off the tank and then looked for air leaks with Snoop. It's the same as soap water.

Matt

 

[Duetech]

One of the best ways to test soldered joints is with air and soap. A little dish soap in an old Fantastic or Windex spray bottle will tell you a lot but be patient watch the joint as some leaks will be nearly microscopic. Test the system, keep it charged then go back an hour later and test again. Also before spraying with soap mildly heat the joint with your propane torch as joints that have been soldered will some times have a flux plug in a leak that will blow out when water or heat are applied so it is better to test with heat and soap while there is low pressure air on the system. just don't over heat or you will be blowing hot solder around and may end up re-sweating the joint...Cave2k

 

[Nofossil]

I made a little fixture with a pressure gauge, an air line quick connect, and a ball valve. I solder it into a zone or line or whatever, and pressurize to 120 psi, then do the windex thing. Also make sure it holds for several hours if possible.

Two 'lessons learned':

1) Make sure everything in the tested section is rated for the pressure that you use to test.

2) Make sure you relieve pressure before applying the torch. I went to unsolder a 1" cap while I still had the loop under pressure. Sounded like a gunshot, and the cap has never been seen since.

 

[Willman]

Sounded like a gunshot, and the cap has never been seen since.

:bug:

 

[Redox]

Ah, yes. The leak check. Where the rubber meets the fire, or something like that. I've been there many times. Refrigerant, glycol, air, water; all leak from somewhere eventually. The leaks I have found...

Our current house was a bank foreclosure and froze hard when the utility cut off the house due to nonpayment. What a mess! What I ended up doing was putting a quick connect onto a female garden hose fitting and screwing it onto the drain valve of the water heater. Pump it up with an air compressor and follow the noise. Much less messy than pressurizing with water. After you fix the obvious (audible) leaks, start soaping up suspected places and look for bubbles. We always found that Dawn dishwashing detergent diluted with some water was as good as anything for making bubbles. After you think you have them all, pressurize one last time to a known pressure and let it sit for a while. Temperature changes will affect the pressure, but if it holds a fairly steady pressure for 24 hours or so, you're probably good to go. Wash off the soap to prevent possible future corrosion and fill'er up. You might not find all the leaks until the system is heated up for a while, but nobody has found a way around that. The good news is that any resulting leaks of this sort are usually small and fixing such small leaks seems to take on less importance as time goes on. Since you probably already have a drain valve somewhere, you're half way there.

Glycol leaks are the worst. That stuff leaks from everything!

I stopped using a flame for leak checking gas lines when I nearly burned down someone's house. It was a porous spot in a brand new cast elbow, probably of foreign manufacture...

Chris

 

[steam man]

At work I occasionaly use a hand held ultrasonic leak detector-wear a pair of headphones and listen for the gas/vapor escaping. I haven't tried that on hydronic stuff at home but it would be interesting.

Mike

 

[Tony H]

We just did my system yesterday the old way with water and a couple valves and drains, all the leaks were out in the boiler shed a couple from the 2" black iron and one of the last one was a connection to the pump isolation valve the I forget to solder at all !! The strut rod holding the bottom of the pipe up was tight enough that there was only a small drip ! Never had that before. I had used tape on all the BI fittings and when we took it apart to fix the drips used tape plus dope with teflon on everything 1" and larger and just dope with teflon in the small stuff and now no leaks or drips. Got the pump running and holding 18lbs right now. Next FIRE !

Tony