Appendix B. Diagnostic Info. & Available System Settings - Lennox ComfortSense L7742U Programming And Application Manual

Appendix B. Diagnostic Information and Hidden Menu Tables
Diagnostic Information Table
Condition
AC power loss for more
than 250ms (1/4 second)
CPU memory error OR
ROM error
Note: If either of these er-
rors occur, the display
goes blank and all relays
are disabled.
Hi temperature protection:
room temp. exceeds 96F
(35.6C)
Local Temp Sensor error:
local temp sensor reads
out of range −40F to 158F
EEPROM error (Power
ON)
EEPROM error (Operat-
ing)
Display Text (Screen1)
TEMP SENSOR ERROR
CALL FOR SERVICE
MEMORY ERROR
CALL FOR SERVICE
MEMORY ERROR
CALL FOR SERVICE
Display Text (Screen2) System Action
Lithium Battery will remember the
clock for 30 days. All outputs will
be off and O/B will remember the
last state.
No Operation
All stages of heat are turned off.
Contact Info. Screen Indoor temp is displayed as "EE"
on the home screen. This will
STOP all temperature related op-
eration.
Contact Info. Screen System shall restore everything to
ENERGY STAR
ate. If lithium Bat tery has charge, it
will remember the previous stored
settings.
Contact Info. Screen System shall operate in normal
mode operation until power off.
Page 39 ComfortSenset Model L7742U Touch Screen 7−Day Programmable Thermostat
Action to Clear / Recovery
Condition
When AC power is restored, normal
operation resumes.
Replace Thermostat
If temperature goes down, it will
start working again. (Need to re-
duce temperature in space.)
User − call dealer number from con-
tact information screen and request
thermostat replacement, OR If the
sensor reads back to within the nor-
mal operating range, the error mes-
sage will be cleared. Start working
again.
User − call the dealer to replace
®
Default and oper- thermostat.
User − call the dealer to replace
thermostat.
table continued on next page