© 2021 Carrier. All rights reserved.
A Carrier Company
Edition Date: 06/21
Catalog No: OG-40MHH-04
Replaces: OG-40MHH-03
40MHH: Owner’s Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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Table 3 — 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.
Reset the circuit breaker or replace the fuse with the specified
replacement fuse.
Power failure
Restart the operation when the power is restored.
Diagnostic lights illuminate.
*
Call your service representative
Voltage is too low.
Call your service representative.
Poor cooling performance
The filter is blocked by dust.
Clean the air filter
Temperature is not set properly.
Check the temperature and reset if necessary.
A window or door is open.
Close the window or door.
The outdoor unit is obstructed.
Turn the unit off, remove the obstruction and turn it back on.
The fan speed is too low.
Change the fan speed selection.
The operation mode is in Fan instead of Cool.
Change the operating mode to Cool or reset the unit.
Poor heating performance
The filter is blocked with dust.
Clean the filter.
The temperature is set too low.
Check the temperature and reset if necessary.
A window or door is open
Ensure all the doors and windows are closed while operating the
unit.
The outdoor unit is obstructed.
Turn unit off, remove the obstruction and turn the unit back on.
Unit stops during operation
The OFF timer is not operating correctly.
Restart the operating mode.
Diagnostic lights illuminate
Call a service representative for service
