Troubleshooting – Lennox International Inc. 43558 User Manual
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TROUBLESHOOTING
SCRAMBLED OR DOUBLE DISPLAY
(numbers over numbers)
NO DISPLAY
ENTIRE DISPLAY DIMS
PROGRAM DOES NOT CHANGE
AT YOUR DESIRED SETTING
AUTO / FAN DOES NOT TURN ON
FAN RUNS CONTINUOUSLY
1. Remove clear Mylar sticker
1. Check terminal connection. A common (C) wire is required for operation.
2. Check battery connections and batteries.
3. Press RESET button with a small pin and hold in for two seconds.
1. Replace Batteries
2. Adjust LCD contrast in the Option Menu.
1. Check that the time is set properly to “AM” or “PM”.
2. Check that the thermostat is not in “HOLD” or “Home Today” modes.
3. Check for the correct day setting.
4. Check any remote sensor readings or weights.
1. Move HG/HE selector to opposite position
1. Check fan setting. It may be “ON” or in Programmable Fan mode “PGMON”.
Solution
Problem
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1. Check that the system selector key is in the correct position (“HEAT,” “COOL”
or “AUTO”).
2. The thermostat may be in the AUTO mode. Look for “AUTO” on the LCDdisplay.
If the Heat and Cool program temperatures are close, then the thermostat re-
quires a larger room temperature change before changing from Heat or Cool.
3. There may be as much as a 4 minute delay before the Heat or Cool system turns
On - wait and check. (Compressor protection delay.)
4. Check your circuit breakers and switches to ensure there is power to the system.
5. Replace batteries.
6. Make sure your furnace blower door is closed properly.
7. Check the position of the Heat Pump or Multi-Stage selector switch.
1. Press the RESET button once with a small pin and hold for two seconds.
The thermostat will need to be re-programmed.
1. Replace unit.
1. Replace unit.
Solution (cont.)
Problem (cont.)
HEATING OR COOLING DOES
NOT GO ON OR OFF
ERRATIC DISPLAY
IF UNIT CONTINUES TO OPERATE
IN THE OFF POSITION
THERMOSTAT PERMANENTLY
READS “HI,” “LO,” OR “Error”
AFTER PRESSING RESET BUTTON
If you experience any other problems, call 800-676-7861 from 8 AM to 5 PM Central Time for technical assistance.