Ontario 5 ton Geo running 24/7

Maurice,
You may recall reading on this website that soldeing/brazing an Evaporator using R22 takes less heat and than soldering/brazing an Evaporator for the latest Freon in use. In fact I remember someone saying it requires a different process of brazing.

I would ask the technician if he is aware of this fact before he uses the lower heat/process and you end up with a poor installation job if you don't have R22 in your Unit.
Maybe a quick review of this process online will make you familiar with the difference so you can offer up a Reference if the Tech Says HUH?