Carrier 40MAHB - System Troubleshooting Guide; Troubleshooting Unit Malfunctions

Copyright 2020 Carrier Corp. D 3300 Riverwood Parkway Atlanta GA, 30339 Edition Date: 11/20 Catalog No. OM-40MAHB-01
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations. Replaces: NEW
TROUBLESHOOTING (CONT)
Table 4 — Troubleshooting
* Diagnostic lights are a combination of lights that will illuminate in the display area on the unit. They are a combination of the lights you see during normal operation.
PROBLEM POSSIBLE CAUSE SOLUTION
Unit/System Does Not Work
 The circuit breaker has tripped or a fuse has
blown.
Diagnostic lights illuminate.*
 Voltage is too low.
 Reset the circuit breaker or replace the fuse with the
specified replacement fuse.
Call your service representative.
 Call your service representative.
Cooling is Not Working Properly
 The filter is blocked by dust.
 Temperature is not set properly.
 A window or door is open.
 The outdoor unit is obstructed.
 The fan speed is too low.
 The operation mode is in Fan instead of Cool.
 Clean the air filter.
 Check the temperature and reset if necessary.
 Close the window or door.
 Remove the obstruction.
 Change the fan speed selection.
 Change the operating mode to Cool or reset the unit.
Heating is Not Working Properly
The filter is blocked with dust.
 Temperature is set too low.
 A window or door is open.
 The outdoor unit is obstructed.
 Check the temperature and reset if necessary.
 Close the window or door.
 Remove the obstruction.
Unit Stops During Operation
 The Off timer is not operating correctly.
 Diagnostic lights illuminate.*
 Restart the operating mode.
 Call your service representative.