Thermostat Wiring Explained - Electrical Online The most basic of systems (such as an older ‘heat only’ forced air / gas furnace with a standing pilot light) only need two wires for control. They connect to a two-wire thermostat (generally a mechanical thermostat with a mercury filled ball connected to a coiled bi-metal strip). wiring a gas furnace part1 - YouTube Click to view on Bing4:35wiring a gas furnace in bill williams hvac class. wiring a gas furnace in bill williams hvac class. Skip navigation How to Wire a 110 volt Furnace Switch & Furnace Switch Receptacle | HVAC Repair Louisville Ky BASIC Author: ryan76cViews: 36K Electrical diagram training - Gray Furnaceman Furnace The wiring diagram helps locate components and wires in the unit that you find in the schematic diagram. The position diagram is a map that shows the position of all the components in the electrical panel. The position diagram is not included in all manufacturer diagrams. Thermostat Wiring Diagrams [Wire Installation] Simple Guide Thermostat Wiring Diagrams. With the top thermostat wiring diagram showing an air conditioning system. The second wiring diagram showing a heat pump system. Finally, the third thermostat diagram showing the average type of split system with an air conditioner or gas or oil furnace used for heating. Wire A Thermostat The basic Heat + A/C System thermostat typically utilizes only 5 terminals. RC - Red Wire (Power 24 Vac) RH or 4 - Red Wire Jumpered (Power 24 Vac) W - White Wire (For Heating Enable) Y - Yellow Wire (For Cooling Enable) G - Green Wire (Controls Fan ON-Auto) The diagram shows how the wiring works. Standard AC with Standard Furnace Control Wiring PDF fileStandard AC with Standard Furnace Control Wiring Standard Furnace Standard Thermostat Standard A/C Condenser 1st Stage Heat (White) 24 Volt+ Fan Only Operation Common Air Conditioning AC Contactor Control Board 1 This diagram is to be used as reference for the low voltage control wiring of your heating and AC system.