Diagnosis
This is usually an issue of insufficient BTU capacity for the room size, heat sources, or air leakage, not a unit malfunction. The A018-10KR is a 10,000 BTU unit.
How to Fix It
Verify the room square footage is within the unit's rated capacity (approx. 450 sq ft under ideal conditions). Close all doors and windows. Use curtains to block direct sunlight. Ensure the exhaust hose is as short and straight as possible; coiled or long hoses reduce efficiency. Set the fan speed to High.
If That Didn't Work
Check for air gaps in the window seal kit. Even a small gap lets hot air in. Use foam weather stripping to seal completely. Measure the actual room temperature with a separate thermometer placed away from the unit's air intake.
Heads Up
The unit's thermostat sensor is near the intake. If hot air from a lamp or TV is blowing directly into the intake, it will read a falsely high temperature and cycle the compressor off prematurely.