Trane SCWM Series Installation, Operation And Maintenance Manual page 46

Operating Principles
High Pressure Limit conditions can be caused by the
following:
• low condenser water flow
• high entering condenser water temperature
• fouled entering condenser water strainer
• TXV malfunction
• refrigerant over charge
• water regulating valve (WRV) malfunction
• faulty discharge pressure sensor
Figure 37. Fixed Speed Compressor Protection Module (MCSP)
46
The Unit Controller's TD7 will annunciate a Limit
Condition if an FS compressor circuit enters one. If the unit
is equipped with WRV, the Unit Controller can open the
valve to allow more flow through the condenser to help
mitigate an HPC trip.
If the VS circuit enters either a High or Low Pressure limit
condition the Unit Controller can reduce compressor
speed to help mitigate either a Low or High pressure
diagnostic trip.
PKG-SVX027A-EN