Chiller Unit Controller Settings - McQuay MicroTech II Operation Manual

Any sensor wired to the CSM must have its Flag set to "Yes" so that the alarm functionality of that sensor is enabled.
The CSM takes action when its sensor inputs are in alarm condition to maintain proper control of the system. See the
Alarm Monitoring and Control section of this document for descriptions of action taken to compensate for alarm
conditions.
Flow Meter Input Calibration
If the chiller system has a flow meter, the flow meter must be calibrated. Enter the actual water flow rate that corresponds
to an output signal of 4 mA (or 2 Vdc) from the flow meter transducer into the Flow Meter Low Calibration Rate variable.
Enter the actual water flow rate that corresponds to an output signal of 20 mA (or 10 Vdc) from the flow meter transducer
into the Flow Meter High Calibration Rate variable.
There is also an offset provided which may be used to compensate for wiring or sensor-to-system error.
Loop Differential Pressure Sensor Input Calibration
If the chiller system has a differential pressure sensor installed across the supply and return chilled water lines, the pressure
sensor must be calibrated. Enter the actual pressure differential that corresponds to an output signal of 4 mA (or 2 Vdc)
from the pressure transducer into the Loop DP Sensor Low Calibration Pressure variable. Enter the actual pressure
differential that corresponds to an output signal of 20 mA (or 10 Vdc) from the pressure transducer into the Loop DP
Sensor High Calibration Pressure variable.
There is also an offset provided which may be used to compensate for wiring or sensor-to-system error.
Some systems require more than one loop differential pressure sensor to properly control the flow to the cooling loads. If a
second sensor is required on your system it may be wired to the spare input (AI-9) and calibrated by entering the low and
high transducer signal into the Spare Low Calibration Value and Spare High Calibration Values respectively. Also, set the
Spare Sensor Type variable to "Second Loop Diff Pressure Sensor". The CSM will then use the sensor with the largest
deviation from setpoint as the control pressure.
Temperature Sensor Calibration
There is also an offset provided which may be used to compensate for wiring or sensor-to-system error.
Service Testing
The service testing inputs allow a technician to test the CSM's analog and digital outputs, the field wiring to them, and the
auxiliary equipment they control. For example, if the Analog Output for Cooling Tower Bypass Valve is set to "100%,"
the cooling tower bypass valve should fully open to the tower.
Always remember to command the Service Testing outputs to Auto after you are finished so that the CSM application can
control the outputs value.
It is important to set the CSM's Control Mode (System Control screen) to Manual Unoccupied to turn the chiller
system off before changing any of the service testing values. Damage to the chiller system components may occur if
these devices are overridden while the system is operating.

Chiller Unit Controller Settings

When a chiller is to be controlled by the CSM, the chiller unit controller must be configured to allow L
commands. Some of the features that exist on the chiller unit controller for stand-alone operation must also be disabled so
that they do not interfere with the CSM's control features. For information on making changes to the MicroTech II chiller
unit controllers, refer to the proper chiller Operation Manual (see the Reference Documents section of this document).
The following unit setup variables must be set in all chiller unit controllers associated with a CSM. These variables, which
are summarized in Table 7, must be set to the values shown in italic. You can find them at the chiller controller's
keypad/display.
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