You're probably OK. Tell the technician what you did when they come back.

The technician probably closed a few valves and purged the system to isolate the unit from the rest of your system, allowing them to find the leak with the Nitrogen test. You and your family should be alright, but be sure to inform the tech before they start working on the unit again.

So. The alternative to the advice so far is not to tell the technician?

Yes, we told the technician and he said it's your luck now. Your condenser might have survived but it is 10 years old might have not survived and have to change it. I am so upset by this that a mistake would cost us so much money.

Yes, the fan on the condenser came on and it ran for a few minutes. So not sure the amount of damage it did. It's a 5-ton goodman condenser. Please someone guide us that can it really be damaged in 10 mins.

" Yes, we told the technician and he said it's your luck now."

Huh? What does that mean? Your refrigerant charge had leaked out of your 10 year old and the tech determined you had a leak inside. The tech "left the nitrogen in the unit"... and left.

Did not the nitrogen then leak out?

By running it with no charge, just what does the Tech claim was damaged? Talk to the Supervisor about the situation and ask why the technician did not disable the unit if there was any risk of damage due to inadvertently being operated!