Carrier XRV, 19XR specifications LEGEND TO TABLES 11A-11J, to calculate the chilled water/brine

TRANSDUCER REPLACEMENT — Since the transducers are mounted on Schrader-type fittings, there is no need to re- move refrigerant from the vessel when replacing the transduc- ers. Disconnect the transducer wiring. Do not pull on the trans- ducer wires. Unscrew the transducer from the Schrader fitting. When installing a new transducer, do not use pipe sealer (which can plug the sensor). Put the plug connector back on the sensor and snap into place. Check for refrigerant leaks.

Be sure to use a back-up wrench on the Schrader fitting whenever removing a transducer, since the Schrader fitting may back out with the transducer, causing a large leak and possible injury to personnel.

Control Algorithms Checkout Procedure — One of the tables on the CVC/ICVC SERVICE menu is CON- TROL ALGORITHM STATUS. The maintenance screens may be viewed from the CONTROL ALGORITHM STATUS table to see how a particular control algorithm is operating.

These maintenance screens are very useful in helping to de- termine how the control temperature is calculated and guide vane positioned and for observing the reactions from load changes, control point overrides, hot gas bypass, surge preven- tion, etc. The tables are:

CAPACITY	Capacity	This table shows all values used
	Control	to calculate the chilled water/brine
		control point.
OVERRIDE	Override	Details of all chilled water control
	Status	override values.
HEAT_EX	Surge/	The surge and hot gas bypass
	HGBP	control algorithm status is viewed
	Status	from this screen. All
		values dealing with this control
		are displayed.
LL_MAINT	LEAD/LAG	Indicates LEAD/LAG operation
	Status	status.
OCCDEFCM	Time	The Local and CCN occupied
	Schedules	schedules are displayed here to
	Status	help the operator quickly deter-
		mine whether the schedule is in
		the “occupied” mode or not.
WSMDEFME	Water	The water system manager is a
	System	CCN module that can turn on the
	Manager	chiller and change the chilled
	Status	water control point. This screen
		indicates the
		status of this system.

Control Test — The Control Test feature can check all the thermistor temperature sensors, pressure transducers, pumps and their associated flow devices, the guide vane actuator, and other control outputs such as hot gas bypass. The tests can help to determine whether a switch is defective or a pump relay is not operating, as well as other useful troubleshooting issues. During pumpdown operations, the pumps are energized to pre- vent freeze-up and the vessel pressures and temperatures are displayed. The Pumpdown/Lockout feature prevents compres- sor start-up when there is no refrigerant in the chiller or if the vessels are isolated. The Terminate Lockout feature ends the Pumpdown/Lockout after the pumpdown procedure is reversed and refrigerant is added.

LEGEND TO TABLES 11A-11J

CCM — Chiller Control Module

CVC — Chiller Visual Controller

CHW — Chilled Water

ICVC — InternationalControl Chiller Visual

ISM — Integrated Starter Module

PIC II — Product Integrated Controls II

VFD — Variable Frequency Drive

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