Never! If it's low on refrigerant it has leaked.
If the system was drained, or leaked out, yes it needs evacuated.If the system was drained, or leaked out, yes it needs evacuated.
Yes! Freon leaks out during the winter months!
Its odorless and colorless.........
The Freon probably needs to be recharged. Any repair shop should be able to do this. They should also test the system for leaks to see why the Freon leaked out to begin with.
Freon isn't a single compound, it's a family of related chemicals. Most freons are colorless and odorless.
If the refrigerant has leaked out, then you can not do a home repair. you need to replace all the pipework and get someone to come in and re pressurise the system. This is a job for a professional.
R-12 freon is colorless and odorless...............
Freon is added to the low side of the a/c system, that is the big line and the capis normally blue in color.
Freon is colorless on its own. The refrigerant oil can have a tan color, while a leak detection dye would be yellow.
you just skipped a step, now you don't have to evacuate the system. But doing that on perpose could cost you a $25,000 fine.
Freon, or same, has likely leaked from the system. You need it recharged. Likely need to fix the leak. Call a professional.