ACS HE Series, Operation And Instruction Manual

Page: 48 / 83

HE Series Central Chillers Chapter 6: 48 of 83
6-4 Chiller Operation
Once the unit’s power is enabled and the controller is turned on (see Chapter 4 for
more details on the operation of the controller) it verifies the flow through the electronic
flow switch. If the flow is not established within 10 seconds the controller will alarm and
disable the refrigeration circuit. Upon flow verification the controller uses the pump tank
temperature setpoint to determine the operation of the compressors.
Elevated sound level and substantially reduced current draw indicate reverse
rotation, after several minutes of operation, the compressor internal protector
trips.
Communication Loss Control
When a drone circuit loses communication with the master circuit it will continue to
operate. It will continue to control until communication is reestablished with the master, a
critical alarm occurs or it is powered down.
Setpoint
When the circuit detects that communication has been lost, the leaving water setpoint
is noted. If the noted temperature is below the chiller’s minimum setpoint, the minimum
setpoint is used as the circuit’s setpoint. If the noted temperature is above the chiller’s
setpoint, the chiller’s setpoint is used as the circuit’s setpoint. Otherwise the noted
temperature is used as the circuit’s setpoint
Local Staging