Repairing Leak on Charged System
Repaired a small leak today in an RTU using proper service practices: recover, repair, filter/drier, micron vacuum, weigh-in. But all the while I was wondering, could I have repaired this with freon in the system (saving a few hours): 1) the leak was tiny and very accessible, 2) system static pressure was only about 90 psi.
I assume the problems with this procedure would have been: 1) excessive heating of refrigerant, 2) safety, 3) may not work at all, as well as other problems of which I welcome you to remind me.
But just wondering . . . has anyone ever successfully repaired a leak without recovering? Maybe by recovering down to 15 lbs or so?
A bead of Sil-floss weighs less than 90 pounds and Fosgene gas takes my breath away
You stand a better chance (although a VERY slim one) of making a repair in a vacuum depending on what you are using to join your tubing/pipe. Any pressure will push out your filler material and leave you with pinhole leaks. Too much pressure can give you a face full of hot solder/braze material. My nitrogen purge was too high ( 5 PSIG) once and I ended up fixing pinhole leaks after a pressure test revealed the leaks.
Lastly, James Mo is right about the phosgene. You'll get enough in your years of service without trying to make repairs under pressure. Do it safely and do it right.
I cant believe you even posted that thought .What do you think happens to the parent metal when you try to weld .That very small leak will become a very large one in a hurry as the parent metal melts releasing a combination of pressurized burning refrigerant and oil under pressure.I know its hot right now but I think you have spent a little too much time in the sun .Use proper safe environmentally responsible methods to repair leaks,if the customer wants to save money then let them find someone else to fix it.At least you can go home at night in one piece Knowing you did the right thing .!!!!!!!!!!!!!!!!!!!!
I'm speechless on this one.
All my leon freaked out!
Yep, I'm often quite crazy.
Originally Posted by graham
Years ago an oldtimer told me he sometimes brought systems down to low pressure before repairing leaks . . . sounded like B.S. and I never gave it that much thought.
But today I was in this experimental mood (surely you've been there) and had this miniscule leak, and late for 2 other calls, and the old guy popped in my head. And since they're quite a few BSing old-timers who frequent this board , . . . off went the question.
Sounds like the answer is an emphatic NO. I appreciate everyone's input.
safe repair without heat or recovery
There is a product used for small leeks. Its about the size of a pen and works like a septic stick. I think you can use a heet gun and rub it on.Never used it ,Dont know the name but have seen it on the shelf.Nxt trip to the suply house ill Check on the name and specs.
Just to add a little more, even though you static is 90, what do you think it will be as you add heat? We all know this is how refrigeration works.
Work smarter not harder.
I saw a repair done on a roto lock under pressure a while back. The "serviceman" took mastic tape and wrapped it around the roto lock fitting and the tubing.
It didnt hold....
The guy who did it has probably 20 years experience in hvac but he works for a hack outfit so he probably is a hack himself.
Its sad isnt it.... some guy spending 20 years doing this work and he comes up on that rotolock and his solution is to wrap tape around it......
Ive seen pvc cement used in vain, all sorts of epoxies...
It's All Good!!!
yeah, I think your Leon must've all freaked out
...sorry,I had to steal it,... just too funny
I once had a leak around a schrader stub. It looked as if it had been repaired before in vain. It had this gray hard substance around. Anyway, I pulled the remaining charge and sanded it off.....not easy. Once it was off, just a matter of brazing the leak around the stub.
I asked the more experienced techs at an RSES meeting one night about this strange sealant. I asked them if they have ever seen this stuff on leak repairs. They said it was a two part epoxy marketed some years back. It never caught on.......wonder why.
"Nearly all men can stand adversity, but if you want to test a man's character, give him power."
You gotta be freakin kidding me !!!!!!!!!!!!!!!