Troubleshooting - Carrier 40MHH Owner's Manual

Troubleshooting

Refer to Tables 2 through 3 before contacting your local dealer.
INDOOR UNIT
Clean Air Filter*
Replace Carbon Filter
Change Remote Control Batteries
OUTDOOR UNIT
Clean Outdoor Coil from Outside
Clean Outdoor Coil from Inside†
Blow Air Over Electric Parts†
Check Electric Connection Tightening†
Clean Fan Wheel†
Check Fan Tightening†
Clean Drain Pans†
* Increase frequency in dusty zones.
{ Maintenance to be carried out by qualified service personnel. Refer to the Installation Manual
The following issues are not malfunctions and in most situations will not require repairs.
Issue
Unit does not turn on when
pressing ON/OFF button
The unit changes from
COOL/HEAT mode to FAN
mode
The indoor unit emits white
mist
Both the indoor and outdoor
units emit white mist
The indoor unit makes
noises
Both the indoor unit and
outdoor unit make noises
The outdoor unit makes
noises
Dust is emitted from either
the indoor or outdoor unit
The unit emits a bad odor
The outdoor unit's fan does
not operate
Operation is erratic,
unpredictable, or unit is
unresponsive
NOTE: If an issue persists, contact a local dealer or your nearest customer service center. Provide them with a detailed description of
the unit malfunction as well as your model number.
Table 1—Periodic Maintenance
EVERY MONTH
EVERY MONTH
Table 2—Common Issues
Possible Causes
The unit has a 3-minute protection feature that prevents the unit from overloading. The unit cannot restart
within three minutes of being turned off.
The unit may change its setting to prevent frost from forming on the unit. Once the temperature increases, the
unit starts operating in the previously selected mode again.
The set temperature has been reached, at which point the unit turns off the compressor. The unit continue
operating when the temperature fluctuates again.
In humid regions, a large temperature difference between the room's air and the conditioned air can cause
white mist.
When the unit restarts in HEAT mode after defrosting, white mist may be emitted due to moisture generated
from the defrosting process.
A rushing air sound may occur when the louver resets its position.
A squeaking sound may occur after running the unit in HEAT mode due to expansion and contraction of the
unit's plastic parts.
Low hissing sound during operation: This is normal and is caused by refrigerant gas flowing through both
indoor and outdoor units.
Low hissing sound when the system starts, has just stopped running, or is defrosting: This noise is normal
and is caused by the refrigerant gas stopping or changing direction.
Squeaking sound: Normal expansion and contraction of plastic and metal parts caused by temperature
changes during operation can cause squeaking noises.
The unit makes different sounds based on its current operating mode.
The unit may accumulate dust during extended periods of non-use, which will be emitted when the unit is
turned on. This can be mitigated by covering the unit during long periods of inactivity.
The unit may absorb odors from the environment (such as furniture, cooking, cigarettes, etc.) which will be
emitted during operations.
The unit's filters have become moldy and should be cleaned.
During operation, the fan speed is controlled to optimize product operation.
Interference from cell phone towers and remote boosters may cause the unit to malfunction. In this case, try
the following:
• Disconnect the power, then reconnect.
• Press ON/OFF button on remote control to restart operation.
EVERY 6 MONTHS
S
EVERY 6 MONTHS
12
EVERY YEAR
S
EVERY YEAR
S
S
S
S
S
S
S
S
S