very gas heat unit is equipped with two Thermal Cutouts (TCO). They are labeled in the wiring diagrams as TCO1 and TCO2. The location of the TCOs in vary by unit (cabinet) size and product type. The cabinet size can be determined by checking the 39th digit of the unit model number:
Precedent Model Number Example of a B cabinet:
On some units, when using the horizontal ductwork configuration, the unit may require a different TCO1 or TCO1 may be in a different location. Locations are shown below, see the unit IOM for more information.
Precedent Light Commercial - Installation, Operation, and Maintenance Manuals
Foundation Light Commercial - Installation, Operation, and Maintenance Manuals
Shown below is the the location of each TCO based on cabinet size.
Precedent A Cabinet
Precedent B/C Cabinet
Precedent D Cabinet
Large Foundation (15-25T)