Slim Ducted Installation Manual
DURASTAR.COM
24
TROUBLESHOOTING
When troubles occur, please check the following points before contacting a repair company.
PROBLEM POSSIBLE CAUSES SOLUTION
Poor Cooling 
Performance
Temperature setting may be higher than 
ambient room temperature
Lower the temperature setting
The heat exchanger on the indoor or 
outdoor unit is dirty
Clean the affected heat exchanger
The air filter is dirty Remove the filter and clean it according 
to instructions
The air inlet or outlet of either unit is 
blocked
Turn the unit off, remove the obstruction 
and turn it back on
Doors and windows are open Make sure that all doors and windows 
are
closed while operating the unit
Excessive heat is generated by sunlight Close windows and curtains during 
periods of high heat or bright sunshine
Low refrigerant due to leak or long-term 
use
Check for leaks, re-seal if necessary and 
top off refrigerant
Excessive heat is generated by sunlight Excessive heat is generated by sunlight
Too many sources of heat in the room 
(people, computers, electronics, etc.)
Reduce amount of heat sources
Poor Heating 
Performance
The outdoor temperature is
extremely low
This model is designed to work down to 
-13°F, however, heating performance 
is impacted at temperatures below 
freezing.
Cold air is entering through doors and 
windows
Make sure that all doors and windows 
are closed during use
Low refrigerant due to leak or
long-term use
Check for leaks, re-seal if necessary, and 
top off refrigerant
The unit starts 
and stops 
frequently
There’s too much or too little refrigerant 
in the system
Check for leaks and recharge the 
system with refrigerant
Incompressible gas or moisture has 
entered the system
Evacuate and recharge the system with 
refrigerant
The compressor is broken Replace the compressor
The voltage is too high or too low Install a manostat to regulate the 
voltage










