ecobee Smart Thermostat Installation

• Working Wi-Fi, Phillips screwdriver, pencil, hammer, and a 3/16 in. bit if you need anchors. The install typically takes 30–60 minutes when a C-wire is already there.^[1]
• In the Enhanced (and Premium) box: thermostat, backplate, screws and drywall anchors, wire labels, optional trim plate, and a Power Extender Kit for homes without a C-wire.^[1][4]
• Download the ecobee app, create an account, and scan the QR code on the back of the thermostat to launch the install path.^[1]

1. Power off. Remove the old thermostat. The app asks you to photograph the wiring and to select which terminals have wires.^[1]
2. Apply the supplied labels, then disconnect the wires and remove the old base. Do not let conductors slip into the wall.
3. Do not reuse jumper wires between Rc and Rh — ecobee handles that internally. The official PEK sheet says the R (or Rc) wire goes to the Rc (or R) terminal on the thermostat, not to a jumper.^[3]

• Mount the backplate (trim plate if the old footprint is large), then land wires on the matching Enhanced terminals: R, C, G, Y1/Y2, W1, and W2/OB as required. Do not jumper Rc/Rh.
• Heat pump O/B: land the reversing-valve conductor on W2/OB (Enhanced) or O/B (Premium). During setup, when an O/B wire is detected, the thermostat walks through air-to-air or geothermal heat-pump questions. If heat and cool are reversed after setup, re-run equipment configuration and change the O/B valve setting (O = valve energized in cool, B = valve energized in heat — use what the outdoor unit requires).^[2]
• Separate O and B wires: some older thermostats are not compatible at all (ecobee publishes a not-compatible list). On some listed Trane models, O goes to O/B and B is used as C/common — only as ecobee’s article specifies for that model. Photograph the old board and check the article before you land wires.^[8]

The PEK is installed at the indoor control board and uses the existing four wires (R, G, Y, W) to also create a C at the thermostat. It is for 24 VAC systems that lack a C-wire. Official later wiring guides state the PEK is not compatible with dual-transformer, fan-coil, or communicating systems — use a real C-wire or another listed method there.

At the thermostat (Enhanced official Diagram 2 / 4):

• PEK’s R → thermostat R
• PEK’s G → thermostat C
• PEK’s W → thermostat W1
• PEK’s Y → thermostat PEK+

The O/B reversing-valve conductor goes directly to the thermostat W2/OB (or O/B) — it does not route through the PEK.^[2]

At the furnace / air-handler board, the PEK’s equipment leads land on Y, W, G, C, and R as shown in the official diagram (the PEK also picks up C on the board). Follow the diagram in the manual for optional Y2 / W2 dashed conductors.^[2]

1. Restore power. The thermostat runs a guided setup and highlights the wires it detected (in white). If a landed wire was not detected, you may power down and re-seat it, or manually tap that terminal in setup if you are sure it is landed.^[2]
2. Homeowner vs Pro path: the Pro path adds fan-coil / multi-speed PTAC options (24 V only). Enhanced can use Y2 as G2 and PEK+ as G3 for multi-speed fans when configured that way — that is not a PEK-without-C-wire job.^[2]
3. You will set system type, fan control, occupied set-points, country and time zone. A 4-digit registration code appears at the end (valid for about an hour) for adding the thermostat in the app. Heating and cooling may wait on a temperature calibration period of up to 20 minutes.^[2]
4. To fix a wiring or equipment mistake later: Menu → Settings → Equipment → Wiring to review, then back and Re-configure Equipment (also under Settings → Installation Settings → Equipment).^[2]

• No power / dark screen: confirm breakers, door switches, and 24 VAC. With a C-wire, measure R (or Rc) to C. With a PEK, re-check the four PEK-to-thermostat landings above and the PEK C connection on the control board. Loose or swapped PEK leads are the usual first-hour failure.
• Short cycling: confirm stages, minimum on-times, and that the PEK is not mis-landed so G or Y is fighting the board. Check the filter and the furnace limit / condensate switch if the equipment itself is dropping out.
• O/B reversed (heats in Cool, cools in Heat): reconfigure the heat pump and the valve orientation. Do not move the O/B wire onto PEK+ to “try it.”^[2]
• Wi-Fi / registration fails: complete Wi-Fi first if the thermostat says “2 steps left” under Registration; codes expire in about an hour. Recheck 2.4 vs 5 GHz and captive portals.^[2]
• On-screen alerts: the Enhanced Setup and User Guide defines alert and status icons (they are drawings, not a public numeric code list). Use the message on the screen, Menu reminders, and ecobee support. The manual also documents “Aux heat running” and related heat-pump threshold alerts, which are configuration / outdoor-temperature issues rather than a failed install.^[2]

1. ecobee — Installing your Smart Thermostat Enhanced (and Premium install video) — https://www.ecobee.com/en-us/installing-your-smart-thermostat-enhanced/
2. ecobee Smart Thermostat Enhanced Setup and User Guide, 2023 (wiring diagrams 1–4, PEK, O/B, setup) — https://assets.ctfassets.net/a3qyhfznts9y/38mOpxuQED3OOIUvYbLshZ/cc711d0d2844dfa61cc8e58e49a9bc4c/Enhanced_setup-user_manual_2023_v1.pdf
3. ecobee — Power Extender Kit thermostat wiring sheet (generic Rc/Rh PEK diagram, 2017) — https://assets.ctfassets.net/a3qyhfznts9y/7wzUl0dU6G8zfHv18E4zPJ/1d4ef614f64f9602ee9cd82d1c141285/pek_wiring.pdf
4. ecobee — Smart Thermostat Enhanced product specifications — https://www.ecobee.com/en-us/smart-thermostats/smart-thermostat-enhanced/
5. ecobee — Smart Thermostat Premium product specifications (terminals, staging, SmartSensor) — https://www.ecobee.com/en-us/smart-thermostats/smart-thermostat-premium/
6. ecobee — Contractor thermostat comparison (terminal lists) — https://www.ecobee.com/en-us/contractors/compare-thermostats/
7. ecobee — Essential vs Enhanced vs Premium (what is in the box; not for electric baseboards) — https://www.ecobee.com/en-us/citizen/which-ecobee-smart-thermostat-is-right-for-your-home/
8. ecobee Help — Separate O and B wires, with or without C — https://ecobee.my.site.com/s/articles/I-have-a-thermostat-with-separate-O-and-B-connectors-and-no-C-connector-Am-I-compatible-with-an-ecobee-thermostat
9. ecobee — Power Extender Kit accessory page — https://www.ecobee.com/en-us/thermostat-accessories/power-extender-kit/