Honeywell CT2800 Owner's Manual - Page 10

Six or more wires If your old thermostat has six or more wires (excluding clock wires attached to the C or C1 terminals), your heating/ cooling system is most likely a variation of a heat pump or multistage system. Your CT2800 Thermostat will NOT work with such systems and should be returned to the place of purchase. See the thermostat compatibility table for information about which programmable thermostat will work with your system. Three thermostat wires If you have three wires for heating only and can operate the fan using the fan ON switch, the CT2800 Thermostat will work with your system. Continue the installation procedure. If you have a three-wire heating-only system and cannot operate the fan using the fan ON switch, the CT2800 Thermostat will probably NOT work with your system. Contact your heating contractor for installation assistance. Wires that are not connected to old thermostat If there are extra wires that do not connect to your old thermostat, do not label them. You will not connect these wires to your new thermostat. Tape off the wires individually with electrical tape and place them where they will not interfere with the operation of the new thermostat. Continue the installation procedure. Five wires connected to old thermostat JUMPER (FACTORYINSTALLED). REMOVE IF 5-WIRE SYSTEM Your new thermostat has a factory-installed metal jumper between the R and Rc terminals (Fig. 15). Remove the jumper before wiring the R and Rc terminals. R Rc WY G Fig. 15. M20127 Thermostat C Terminal This thermostat does not use the C wiring terminal. 69-1638-1 10