The blower in the Rheem Classic 90 Plus RGRA model is designed to channel warmed air out from the furnace and into the ductwork. Blower systems are only made from a few basic components, including fans, fan belts and the motor to operate the fan. But in many cases, some adjustments to the blower system are possible, from simple controls to complex, automated systems.
RGRA model blowers come with basic on and off control switches you can use to start or shut down the blower. This is one of the few control options you have as a homeowner, and you should rarely need to use it. The blower is designed to remain open and start based on signals from the furnace. The only time you would need to turn the blower off would be to clean it or remove it entirely from the system.
This furnace model has a blower system designed for more detailed adjustments. These slide-out blower components can be used to match the airflow created by the blower to the size of your ductwork and home. These advanced adjustments must only be completed by a technician that specializes in setup of these units. Do not try to make major blower adjustments yourself.
Rheem models such as the RGRA also have multispeed fan motors. This is an automatic adjustment that occurs when the furnace is working. When the furnace only needs to create a small temperature difference, or when the furnace is starting and needs time to reach a full temperature, the furnace can use a lower fan speed to save energy, then adjust to a higher speed later on when the temperature change increases. You do not need to make these changes; they should happen automatically.
Adjusting blower speeds or capabilities must not be confused with sizing the furnace itself. No matter how the blower is set, the furnace is designed to heat a certain amount of space. You cannot change how much heat the furnace produces by changing the blower speed. Blower speed can help you maintain the comfort of your home and make slight changes, but you will need a different Rheem furnace size to actually heat a larger space.