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Wiring guide

This section provides detailed information on the wiring of GEO. There are two main types of HVAC system used, conventional and heat pump. If you are not sure which one you have please check our handy HVAC glossary to find hints for how to check.
For a more step by step guide to installing GEO please go to our quick start guide or support videos section


If you have separate RH and RC wires, please remove the RED RC-RH shorting cap from the back of the thermostat.

Heat pump

For all Heat Pump configurations, please ensure you reposition the YELLOW Y1-W1 shorting cap so that it is cover both pins on the back of the thermostat.

NOTE #1: Precautionary notice for Heat-Pump systems! If “O” and “B” wires are BOTH present in your wiring, install old “B” wire onto LUX “C” terminal.

NOTE #2: For Heat-Pump systems only, if there is also an “Emergency” Heat (E-wire) in addition to the “Auxiliary” Heat wire, this can typically be taped off and not used. If the electric backup heat will not operate, this “E” wire can be added to the existing Aux Heat wire on the “W2” terminal.

NOTE #3: This thermostat is not compatible with heat pump applications that use a “Y2” wire.

NOTE #4: Most heat pump systems use the “O” terminal for the Reversing Valve. Some brands however use “B” for this purpose (such as RHEEM, RUUD, and BARD as examples). There will NOT be an “O” wire present in the original wiring for this type of heat pump application.

NOTE #5: This terminal is only used for non heat-pump, conventional gas and oil furnaces and hot water boilers. For heat-pump units, the “Y1” terminal is used for both cooling and heating signals, and the electric Aux Heat wire is connected to our “W2” terminal.