Most serious accidents occur about three years after people have started working as hvacr technicians. At that point, they seem to think they know everything and start taking risks.
They take shortcuts, such as leaving safety glasses in the vehicle.
Another example is carrying a toolbox, refrigerant drums, and other material up a 20-ft ladder using one hand. This is dangerous, and has caused serious injury.
Some service companies purchase large cylinders of refrigerant and recharge this refrigerant into smaller drums to save money. This is not only illegal, it is dangerous.
This service call reveals a system that is undercharged, requiring leak repair and recharging. The leak is found and corrected.
You have other calls and decide to quicken the recharging by heating the refrigerant drum with a turbo torch. Since you have inverted the drum, you are driving raw refrigerant into the compressor low side with the compressor running.
Wow! Goodbye crankcase oil. It is possible to drive the crankcase oil into the compression chambers, which could cause broken valve reeds or worse. (Always charge a system into the low side as a gaseous vapor with the compressor running. Even then, watch for oil turbulence or low oil level in the crankcase sight glass.)
Since you are heating the drum on the gaseous side, a black spot appears on the surface of the drum. You shut off the torch and feel the drum.
A blister forms on your palm. Go get your burn ointment. Another 10 sec and the drum would have exploded. A turbo torch will create heat to 2,500Â°F and allow metal fatigue to the point of destruction in 60 sec.
The disposable drums now in use have a wall thickness one-quarter of the returnable type years ago. Even then, you could not return these drums if they had burn marks. The safest way to warm the drum is to place it in a tub of warm water (90Â°), assuming the system pressure is lower than the drum pressure.