Furnace Interlock Wiring Diagram. Safety interlock switch wiring diagram. In this hvac installation training video i show how to wire the low voltage thermostat wires into a furnace and ac unit.
Im thinking i would need a 3 way switch at the bathroom fan. First i do not know the reason behind this since this bathroom fan exhaust to the outside ducted to the outside. Leave the existing black connected.
What i did was run 143 from fan switch box to a central switch then a 142 to a relay box to run the furnace.
Reinstall the switch on casing and plug back its wires. Recommended cold air return ductwork layout may dif fer depending on model stale air to outside fresh air from outside fresh air to living areas fantech. The hb has a spst. Im thinking i would need a 3 way switch at the bathroom fan.