Diagnosis
The refrigerant circuit is likely compromised. This is most often due to a kinked or severely crushed exhaust hose, which causes high pressure and forces the compressor to shut off, or a slow refrigerant leak.
How to Fix It
Inspect the exhaust hose assembly first—it's the most common culprit.
- Detach the hose from both the unit and the window bracket.
- Fully extend it and check its entire length for sharp bends, pinches, or crushing. The inner flexible duct must be able to expand freely.
- Reattach it, ensuring it's as straight and unobstructed as possible.
If That Didn't Work
The unit may have lost its refrigerant charge due to a leak. Listen for a faint hissing sound near the hose connections or the rear coil. If you hear it, the leak is confirmed.
Heads Up
Refrigerant issues are not user-serviceable. If the hose isn't kinked and the air isn't cold, you need a professional HVAC technician to diagnose and potentially repair a leak. Continuing to run it can damage the compressor.