[Richard and Rhonda]

They are R22. I have topped one of mine off. As others have said, you need gauges, knowledge, and R22. You need a license to purchase R22.

Start by cleaning both the condenser (in the basement bays) and the evaporator fins. Dirt will hurt the cooling. Next, measure the outlet temp by using an electronic thermometer. I use a cheap one from any kitchen section of wally world. My dometic units produce 65 to 70 degree air with 100 outside temp.

If you need more specific info, I have inlet and outlet pressures recorded in my coach log book.