ecobee3 Wiring Diagrams – ecobee Support This diagram illustrates the wiring connections for a heat-pump system with auxiliary heating. W2, AUX and or E (Emergency) wiring connections will normally connect to the ecobee3 W1 terminal. ecobee3 manages auxiliary heating through the W1 & W2 (if there is more than 1 2 stage furnace with 1 stage wiring : ecobee - reddit 2 stage furnace with 1 stage wiring. What i thought was to maybe move the main ecobee unit to the furnace room in the basement and run new 2 stage supported wire to it from the furnace and then have the ecobee remote sensors throughout the rest of the house.Top responsesYou can use the PEK to get an extra wire for second stage heat. https://supportee/hc/en-us/articles/227874687-2 read more4 votesWow i never even thought of that. That is absolutely what I'm going to do. Thanks so much!1 voteBrilliant!1 voteSo I have also only have 5 wires and two stage cooling and 2 stage heating the furnace in is only hooked up as one stage as the controller on the furnace read more1 voteYou're going to need an extra wire.1 voteThat's what I thought. I was hoping to gain an extra wire using the pek. I guess I'll continue to let the stat control the two stage cool and let the furnace handle it's read more1 voteSee all Installation guide - ecobee PDF filecall ecobee support to help with wiring. RC RH G Y W C. 11 Step 3. Install Power Extender Kit (PEK) Some thermostats do not have a C-wire. Furnace (cover panel removed) Tip: The control board will generally have R, G, Y, W, C terminal designations. Control board Wires to thermostat R G Y W C. 13 Compatibility Checker Smart Wi-Fi Thermostats by ecobee Check if your home heating and cooling HVAC equipment is compatible with ecobee smart WiFi thermostats.