Troubleshooting - Lennox MHA Series Manual

Timer Operation
Timer ON and Timer OFF are used to turn on and turn off
the indoor unit at selected intervals.
Timer ON Operation
1. Press the Timer ON button. The Timer ON icon, the last
auto-on time, and "h" will display.
2. Press the Timer ON button again to set the amount
of time before the indoor unit begins operation. Each
press will increase the time in half hour increments
until 10 hours, then the increment becomes 1 hour.
Timer OFF Operation
1. Press the Timer OFF button. The Timer OFF icon, the
last auto-off time, and "h" will display.
2. Press the Timer OFF button again to set the amount of
time before the indoor unit stops operation. Each press
will increase the time in half hour increments until 10
hours, then the increment becomes 1 hour.
Modify Timer ON/OFF settings
1. Press either the Timer ON button or the Timer OFF
button to modify that setting.
2. Use the up arrow and down arrow buttons to change
the timed operation intervals.
3. Set the timer to 0.0 to turn off timed operation.

Troubleshooting

If any of the following faults codes appear on your indoor
unit, please contact your li censed professional HVAC
installer (or equivalent) or a service agency.
Table 4. Faults Codes Displayed on Indoor Unit
Code Description
E0 Indoor unit EEPROM error
E1 Communication error between indoor unit and outdoor
unit
E3 Indoor fan speed error
E4 Indoor return air temperature sensor error
E5 Indoor coil temperature sensor error
EC Low refrigerant
EE High water level alarm
F0 Outdoor current overload sensed
F1
Outdoor ambient temperature sensor error
F2
Outdoor coil temperature sensor error
F3
Compressor discharge temperature sensor error
F4 Outdoor unit EEPROM error
F5 Outdoor unit fan speed error
P0 Inverter module IPM error
P1 High or low voltage protection
P3 Outdoor unit low temperature lockout
P4 Compressor drive error
P6 Compressor high-pressure or low-pressure switch
open
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