I'm posting this in hopes that i can get some good insight on the precarious situation I'm in right now and possibly prevent this from happening to someone else. So here goes..
I have a McQuay Chiller M/N: PEH087, S/N: 57B0076200 holding roughly 911 lbs of R-134a. We were taking the machine down to perform some mundane leak repairs, nothing serious. We contracted an independent refrigerant recovery service to pull the gas due to the amount of gas. The day before the recovery service shows up, I isolate and drain the evap and condenser barrels. When the recovery service arrives they hook their machine up and begin to suck harder than a crackhead hooker. They end up recovering roughly 930 lbs out of the machine, not surprising considering that amount of work that has been performed on this machine previously. Once they left we broke the 15"wc vacuum with nitrogen to 15psi. We then used the pressure on the machine to push the oil out of the sump. When we come back the next day we are surprised to see there is no pressure on the machine. We re-pressurize and find nitrogen blowing out of the condenser water pressure gauge ports, OH SH*T! There are tubes busted.....
We drop the heads and found the entire bottom row of tubes in the condenser which is technically the subcooler are blowing out nitrogen. I am having an Eddy Current test done tomorrow to check the rest of the tubes for damage. I am hoping it is just the seven tubes on the bottom row that ruptured. Here are a couple of questions i have, any input is appreciated!
1) In speaking with McQuay, they say i can plug up to 12 tubes in the subcooler but do not recommend plugging them. They would rather see them replaced. There are a total of 161 tubes in the subcooler and 450 total in the condenser. What should i do?
2) How hard is it to replace a tube that has swollen and ruptured? Any company's in the MD/DC/VA area that anyone recommends for retubes?
3) What are the chances that the refrigerant he pulled out has moisture in it? I assume it does, just not sure what to do with it.
4) I also have to assume there is a negligible amount of moisture in the machine now, shouldn't be a lot since the tubes were drained just the water laying in the sag of the tube. Do i just plan on an infinite amount of vacuum pump oil changes? Or maybe a dry ice trap?
In hind sight , I should have just run water through the barrels while the refrigerant was being transferred but due to other system repairs i was unable to..... Thanks for any comments!