If you personally do any repairs to that crappy old radiator or air handler, then management can shift blame and financial loss onto you when (not if) it ruptures and floods, maybe taking out a boiler or water heater in the process.
I thank you for being concerned about my legal/financial safety, but it's not the issue.
I happened to run into one of the two maintenance guys on the elevator. He was in a partial stupor, smelt of alcohol, and was carrying, with his tools, a cup whose contents he was accidentally spilling on the floor. One of the other passengers advised him, "Hey, you're spilling the good stuff." The maintenance guy awakened from his stupor a bit and realized that he was spilling his drink. He corrected its level and said, "Damn, I lost a lot."
I saw him again later and I asked about the heater. He said it needed "a new coil-thing". He then added that "We can't do that." I don't know if he meant the inhibiting factor was his skill, budget, or license.
I'm going to try to find some kind of plug I can solder into the hole. A rubber one might not be good considering the pipe gets hot.