In Figure 3, RBH, RYH indicate HI-TEMP. RBL, RYL indicate LO-TEMP. D is the differential between stages.
Figure 5 shows typical wiring for the control of a two speed ventilating fan. When control temperature reaches the dial setting, the low temperature switch starts the fan on low speed. If the space temperature continues to rise, the high temperature switch supplies power to the high speed motor winding while disconnecting the low speed winding.
Figure 6 shows a typical hookup for a two speed volume fan application. The fan starts when the temperature reaches the dial setting. If the temperature continues to rise, the damper motor is energized by the high temperature switch.
Figure 7 shows typical wiring for a combination heating and cooling system automatic changeover. A temperature increase to dial setting turns off the heating system when the R-B low temperature switch contacts open. An increase of approximately 3F° (1.7C°) turns on the fan or cooling system through the R-Y contacts of the high temperature switch.
Figure 8 shows a typical hookup for two stage heating. On a temperature drop to dial setting the first stage heating turns on. If the temperature continues to drop about 3F° (1.7C°) the second heating stage turns on.