Low Suction Pressure/High Superheat

1. Unit Undercharged
2. Kinked Suction Line
3. Restricted Liquid Line
   • * Kinked
   • * Plugged Liquid Drier
4. Metering Device Restricted
5. Moisture Freezing at Metering Device
6. Clogged Metering Device
7. Incorrect Metering Device (undersized)
8. Bad TXV
9. Incorrect TXV Superheat Setting

Note: On systems with more than one TXV it is possible for one TXV to fail and the other to work. This will result in a Low Suction Pressure and High Superheat. Each TXV must be checked to determine which valve is functioning correctly.

Note: Smaller, five ton and less, TXV's generally have fixed superheat settings. Larger TXV's generally are field adjustable; however, superheat adjustments should only be performed by a technician that fully understands TXV's and superheat.