Issue: 
These are the offical guidlines for Additional oil Charge for FM, AFX, CM units.

Product line: 
FM35, FM40, FM50, AFX and CM.

Environment:    
North American Products.

Cause:   
Guidelines for Oil Charge.

Resolution:  
Follow Guidelines Below.

Note that these unit utilize R22 Refrigerant and Mineral oil will be the oil of choice. If a system requires over 30lbs of refrigerant additional oil will be required to ensure proper oil return of the system.   During normal operation the oil level should be slighly above 1/2 of the sight glass.  Ensure the oil is clean and free of acid if the sightglass should become discolored.