The specific fuse that controls or protects the low-voltage control circuit connected to the blower relay and thermostat is a small, automotive-style blade fuse—typically rated at 3 amps or 5 amps—located directly on the integrated electronic control board inside the indoor air handler or gas furnace compartment. This low-voltage fuse protects the transformer and control board from short circuits in the thermostat wiring. In addition to this control board fuse, the high-voltage 120V or 240V power supplying the heavy-duty blower motor itself is protected by a dedicated standard circuit breaker located in your home's main electrical service panel. You can locate the control board fuse by turning off power and removing the indoor unit service panel. You can verify that the correct fuse is inspected when checking for a broken internal wire.
1 votes
Marked as accepted