Physical Installation and Wiring
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WARNING
Voltage hazard. Can cause electrical shock or equipment damage.
Turn off all power to heating and cooling equipment before beginning installation.
2 Remove the existing thermostat cover from the wall plate. Leave wires attached.
Consult instructions that came with existing thermostat as needed.
The look of your existing thermostat may vary
Thermostat | Wall plate | |
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3 If your existing thermostat is battery powered:
Look to see if there is a 24 Volt Common wire attached to your existing thermostat. That wire is required to power the new thermostat. It is typically (but not always) colored blue. With battery powered thermostats, it most likely will not be connected to the HVAC unit. It is typically identifi ed with one of the following terminal names: C, X, B, COM
If your existing thermostat is battery powered and did not use the 24 Volt common wire, contact a qualified heating and cooling service contractor as needed to properly attach the wire.
4 Locate the wiring labels located in the box with the new thermostat.
| B |
| C | E | F | G | O | L | Y1 | Y2 | ||
| B |
| C | E | F | G | O | L | Y1 | Y2 | ||
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| Rc | Rh | X2 | T | W1 | W2 | W3 | X | Y | |||
| R |
| R |
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| a | ||
| R |
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| R |
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| Rc | Rh | X2 | T | W1 | W2 | W3 | X | Y | |||
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5 Label the wires on your existing thermostat to match terminal names.
Wire colors are not necessarily an indicator of which labels should be used.
a.Look at where each wire is connected to the existing thermostat and fi nd the letter shown next to that wire terminal.
b.Peel off the matching label and wrap it around each corresponding wire.
c.If you have a terminal with a letter that is not shown on the label, wrap a piece of masking tape around that wire and write down that terminal name on the tape.
Y
Y
W2
W2
E
E
G R O
G | RcR | O |
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C | ! |
Wire colors and
Cletters may vary
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