Free Rheem gas furnace manuals that include wiring diagrams can be found on Inspectapedia and Manuals Online. Rheem does not typically provide consumers with wiring diagrams for gas furnaces, but a local heating, ventilation and air conditioning specialist may be able to provide the diagrams.
The gas furnace model number is required to ensure the manual and wiring diagram is compatible with the furnace. A general Internet search for Rheem wiring diagrams results in several images, but most are not identified with brand names or model numbers. Wiring of a gas furnace should be completed by a trained HVAC professional.