The 3-amp fuse on the control circuit board protects the 24-volt transformer from overload caused by control circuit wiring errors.
Why should the blower and burner never be operated without the blower panel in place?
The unit is equipped with an electrical interlock switch that interrupts all power when the panel covering the blower compartment is removed. Electrical supply to the unit is dependent upon the blower panel being in place and properly positioned.
What should be checked before troubleshooting the furnace?
Visual checks should be made to ensure power to the furnace and ignition control module is ON, manual shut-off valves in the gas line are open, all wiring connections are secure, and the sequence of operation is reviewed.
