Honeywell T8131A Owner's Manual - Page 8

Replacing a Clock Thermostat that has C or C1 Clock Terminals? If you are replacing a Honeywell Chronotherm® Thermostat, you may find one or two wires that go to the C or C1 clock terminals on the Chronotherm® Thermostat wiring wallplate. Do not allow them to touch, or you can damage your transformer. Disconnect the wires and wrap them separately, using electrical tape. Do not wrap them together. Place the wires where they do not interfere with the operation of the new thermostat. Record the colors and terminal designation labels of the remaining wires. Six or More Wires? If there are six or more wires (excluding clock wires attached to terminals), you most likely have a variation of a heat pump or multistage system. This thermostat is not compatible with such systems. If you would like information about which programmable thermostats will work with your system, call Honeywell Customer Assistance at 1-800-468-1502. Three Thermostat Wires? If you have three wires for heating only and can operate the fan using the fan ON switch, this thermostat will work with your system; however, some hot water (zoned) heating systems have three thermostat wires. The thermostat will not work without installing an isolating relay on these systems. For details, call Honeywell Customer Assistance at 1-800468-1502. 8 69-0887-1