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Glossary
C wire
The “C” or common wire brings 24 VAC power to the thermostat from the heating/cooling system.
Some older mechanical or battery operated thermostats may not have this wire connection. It is
necessary for establishing a Wi-Fi connection to your home network.
Heat Pump heating/cooling system
Heat pumps are used to heat and cool a home. If your old thermostat has a setting for auxiliary or
emergency heat, you likely have a heat pump.
Conventional heating/cooling system
Non–heat pump type systems; these include air handlers, furnaces or boilers that run on natural gas,
oil or electricity. They may or may not include an air conditioner.
Jumper
A small piece of wire that connects two terminals together.
MAC ID, MAC CRC
Alphanumeric codes that uniquely identify your thermostat.
QR Code
®
Quick response code. A two-dimensional,machine-readable image. Your wireless device can read
the black and white pattern in the square and link its browser directly to a web site. QR Code is a
registered trademark of DENSO WAVE INCORPORATED.
