T116_O: Suction Pressure Floodback Protection
Status
3-strikes, permanent lockout.
Description
The compressor drive controller has detected suction line is colder than the saturation temperature (no superheat)
Expected Operation
Operation will continue with reduced operation.
Cause
1. Check superheat, if it is low or there is no superheat, the compressor may be flooding back with liquid.
2. Locate the sensor on the UODC connected to P6. This is the ambient sensor. Trace it to verify it is indeed the ambient sensor. For Cube units (Fan blows up) it is located below the control box. For RD (horizontal Discharge) is is located in the back of the unit up toward the top of the coil but just mounted measuring ambient air.
3. Check sensors connected to P7. There are two sensors. One should go to the outdoor coil (diagram says comp coil temp). The other should go to the suction line between the outdoor coil and reversing valve. Make sure these are not swapped. You can test it by warming one sensor to verify which is which.
Solution
1. IF there is no or extremely low superheat, verify system is not overcharged or the active metering device is not stuck open.
2/3. Verify sensors are where they are supposed to be and that two of them are not swapped. Ambient sensor goes to P6, Outdoor coil sensor goes to P7, closest to P6, Outdoor Suction sensor is also in P7 but closer to P3. See wiring diagram for detail
