Step 1: Test the current system
Verify that the heating and/or cooling system is operating properly before you try to install the new thermostat.
Do not test the system by shorting electric terminals at the furnace or air conditioner. This may damage the thermostat.
Step 2: Check wiring to confirm low voltage thermostat system
Caution
: Verify that the system is 24 VAC. If the old system is labelled as 120 or 240 volts or has wire nuts, the system is high voltage. Do not install the thermostat to a high voltage system. For more information, check out the device’s
product manual
or scroll to the FAQs below for a breakdown of non-compatible installation options.
Identifying high voltage system
It has 2-4 thick, 14 gauge wires coming out of the back of the thermostat
Wires connect with wire nuts to corresponding wires coming out of the wall
It is labelled 110v, 115v or 240v
Identifying low voltage system
It will have between 2-9 thin, 18 gauge wires that come from the wall and connect to the thermostat terminals.
Wire terminals will have labels such as C, O, W, W2, Y, Y2, R, RC, RH, G, etc.
Step 3: Turn power off heating and cooling
Turn all heating and cooling systems off. This can be done at the circuit breaker or you can turn off the power to the furnace at a switch nearby. Use a voltage detector to make sure there is no live current.
Caution
: Do not remove the existing thermostat until power has been turned off at the circuit breaker.
Warning
: You can blow a transformer by not shutting off the HVAC/Furnace when changing thermostats. If you touch the C and R wires together you can blow the transformer or a fuse.
It is unlikely, but you can also burn up a thermostat by plugging in the wrong wires into the wrong terminals. Make sure you do not match color.
Also, make sure you don’t plug in high voltage (thick black wires) into the thermostat as this can burn up the thermostat.
Step 4: Remove the thermostat cover
Remove the cover from the existing thermostat. Do not disconnect the wires yet.
Tip
: Take another picture of the wires to document connections for easy reference. Do not disconnect wires before labelling them.
Step 5: Label all existing wires
Label all existing wires, one at a time, with the labels provided. Make sure the wires are labelled correctly. If you have an unidentified wire, it may be necessary to identify the wire where it connects to the heating or air conditioning equipment.
Step 6: Remove the old thermostat
Loosen the screws that are holding the wires in place and use your needle nose pliers if needed to disconnect all the wires. The wires might be tightly connected to the existing thermostat and require extra force to remove. If you do not have enough slack to label the wires, remove them one at a time and label them as you remove them. Unscrew the base plate from the wall to remove the old thermostat.
Tip
: Remember to secure the wires so they don’t fall into the wall. You can do this by wrapping the wires around a pencil.
Step 7: Install new baseplate
Use the bubble level provided on the back plate as a guide. Mark where the screws will go with a pencil through the screw holes on the back plate.
If necessary, use the trim plate to cover up any marks or holes left from the old thermostat. Attach the trim plate before securing the back plate to the wall
Drill holes with 3/16” drill bit to tap in the drywall anchors for added support
Note
: Before drilling, check that you are not drilling into electrical wires.
Step 8: Connect the wires
Reconnect the wires to the new thermostat by matching the wire label to the corresponding terminal. When inserting the wire, you do not need to press down on the terminal tab. Once the wire is fully inserted, give it a slight pull and it should be locked in place. Take a picture for reference later. This information will be needed when configuring the thermostat.
Make sure each wire is stripped to ⅛” before connecting
If you make a mistake connecting the wrong wire to a terminal, press down on the terminal tab with a pen to release the wire
Note
: Do not press too hard on the terminal tab and use your pliers to remove the wire.
If you have a R wire, connect it to RH
If you have a RH and RC wire, remove the black jumper in the lower left corner of the back plate terminal board with needle nose pliers (see figure below)
If you have extra wires do not install them in the new thermostat. Please contact your local HVAC professional for additional assistance
Note
: The C wire is not needed to complete a thermostat installation. It provides a constant 24 voltage to the thermostat. If the C wire is there, then we use it with the batteries as a backup.
If there is no C wire, we can use the Smart thermostat with just the batteries. There are many cases where older houses only have the RH and W wire. The thermostat will just be running on the batteries itself and will not drain the batteries. They will last up to a year maybe longer depending on usage.
Step 9: Install the batteries
The thermostat can be powered by batteries or 24 VAC. If a wall transformer is used to power the thermostat, connect between C and RH. Ensure the batteries are installed following the specified polarity markings on the thermostat.
Step 10: Attach the Smart Thermostat
Verify that any excess wire is tucked back into the wall to allow room for the thermostat to sit flush against the back plate. Press the thermostat body firmly into the back plate mounted to the wall. Ensure that the pins on the body are correctly aligned with the header attached to the terminal board on the back plate. Failure to do so could cause damage to the thermostat.
Step 11: Turn power back on
Restore power to all the heating and cooling systems. This can be done at the circuit breaker.
Step 12: Connect your Smart Thermostat to the Control Panel or Automation Hub
Follow the appropriate steps below for connecting the smart thermostat to the main control panel or hub depending on which system you are working with.