The AP (HP) transducer is factory set to 39 bar (565 PSIG). The manual AP (HP) manual reset switch is set for 42 bar (609 PSIG). The AP (HP) relief valve is set to release refrigerant at 45 bar (652 PSIG). It is possible that the unit will totally shut down on (609 PSIG) the manual AP HP) switch. In order to avoid this situation and keep as much of the system running as long as possible in an AP (HP) situation the press f. Parameter in the gr3 control can be adjusted to shut down one compressor in a tandem circuit. If the AP (HP) pressure continues to rise the second compressor in the circuit will be shut down. If the AP (HP) condition remains the transducer will shut off the last compressor on the third (3) occurrence. If the AP (HP) transducer does not shut down the compressors; the manual AP (HP) switch will trip at 41 bar (609 PSIG). Shutting down the circuit permanently. The pre-alarm changes to a permanent AP (HP) alarm after three pre-alarms have occurred. This AP (HP) transducer adjustment will allow you to run the affected NRL circuit in a reduced capacity until the problem is resolved permanently. On start-ups we now recommend setting the parameter press f. To 32 bar when setting up the unit for the first (1) time.
