Necessary to evac prior to new charge?

[berad]

Originally posted by billva
any time a system is opened to the atmosphere it needs to be evacuated of non condensibles and a filter/drier installed.

You have to be careful of this statement. When it comes to a fresh install anyway. Many brands have a liquid line filter dryer installed inside the unit and it would be bad to add a second one in-line. I've been jumped by people over this before and had to shoe them the dryer inside the unit. One time this happened and they still didb;t believe me after seeing it because it was one of the small copper exterior dryers and they didn't know what they were looking at. I had to have Trane fax them that yes this is a dryer and no another one is not required. On the flip side, when performing service/repair work and I open up the system I remove that factory dryer and install a new one. Most shops in my area don't even know it's there and just throw on a second dryer. Can you say flaming compressor death?

[kdawg]

The reason I seem to be favoring the r410 system is because it seems to be where the future of residential home AC is going, whereas r22 is being phased out. That being said, parts and service for r410 will decrease over time and r22 will do the opposite. Since I am investing on a higher effeciency unit, I figured its cost over its lifespan will be less. The way I see it this unit should not need replacement for 25-30 yrs or greater. At that time service should not be complex to find.