Lennox Error Code 542

Priority condition: Service Soon Possible Causes: • Zone temperature sensor reading out of range. • Check for loose or incorrectly wired connections at the zone sensor or damper control module terminals. • Open or short zone temperature sensor detected for more than five second. • More than one zone sensor has the same assigned zone number. Check zone sensor(s) zone number assignment. System Response: • Both types of zone sensors will display “--” as the indoor temperature on the main screen. • Damper control module will operate in central mode (all dampers open) in both moderate and critical priority conditions. • If after 10 minutes the condition does not change, the applicable alert code (542, 543, 544 or 545) is escalate by the Lennox communicating thermostat to critical. System will continue to operate in central mode. • At the Lennox communicating thermostat, only zone 1 screen will be available. NOTE: The Lennox communicating thermostat will display the alert code as “Problem (Zoning Control)”. Email notifications will describe the issue as “ Zone “X” Temp Sensor Problem.