27
REMOVE THE CONTROLS/DRIVE ENCLOSURE —
Confirm that the power supply disconnect is open and all
safety procedures are observed before removing the VFD. This
procedure minimizes the number of sensors and cables that
need to be disconnected.
1. For Q and R compressors, close the 2 filter drier isolation
valves (Fig. 21) and the 2 VFD isolation valves. Isolate
the refrigerant charge into the condenser to prevent a re-
frigerant leak if one of the motor terminals is accidentally
damaged during VFD removal or installation. For Q and
R compressors, evacuate the VFD coldplate through the
Schrader valve (Fig. 21) on the VFD drain isolation
valve.
2. Remove the shipping bracket between the VFD and the
compressor if it is still in place. See Fig. 22.
NOTE: For seismic units, do not remove the shipping
bracket.
3. Remove any conduits that bring power to the VFD.
4. Remove the nuts that secure the terminal box transition
piece to the motor housing.
5. Disconnect the motor leads from the motor terminals
(Fig. 23). Note the position of the motor terminal cable
lugs so they can be reinstalled with sufficient clearance
away from surrounding structure.
CAUTION
Do not rig the condenser before the control center and
compressor are removed. The condenser/compressor
assembly has a high center of gravity and may tip over
when lifted at the tubesheet rigging points, which could
result in equipment damage and/or serious personal injury.
WARNING
Do not attempt to remove the VFD without first closing the
refrigerant isolation valves. Failure to do so during VFD
removal will result in an uncontrolled refrigerant leak. A
refrigerant leak can damage the unit as well as displace
oxygen, causing asphyxiation.
OPTIONAL
HOT GAS
BYPASS LINE
EVAPORATOR
REFRIGERANT
LIQUID
TEMPERATURE
SENSOR
COOLER
REFRIGERANT
PUMPOUT
VALVE
Fig. 19 — Evaporator Refrigerant Liquid
Temperature Sensor on Bottom of Cooler
(Units with Q,R Compressors Shown)
a23-1635
LEAVING CHILLED
LIQUID TEMPERATURE
SENSOR
ENTERING CHILLED
LIQUID TEMPERATURE
SENSOR
ENTERING CONDENSER
LIQUID TEMPERATURE
SENSOR
LEAVING CONDENSER
LIQUID TEMPERATURE
SENSOR
Fig. 20 — Chiller End View
(Q,R Compressors Only)
a23-1563
VFD
REFRIGERANT
COOLING
ISOLATION
VALVE
VFD
REFRIGERANT
STRAINER
FILTER DRIER
ISOLATION VALVE
FILTER
DRIER
MOTOR
COOLING
SIGHT
GLASS
FILTER DRIER
ISOLATION VALVE
SCHRADER
VALVE
VFD DRAIN
ISOLATION
VALVE
Fig. 21 — VFD Refrigerant Isolation Valves
(Q,R Compressors Only)
a23-1663
SHIPPING BRACKET
(FOR SEISMIC UNITS,
DO NOT REMOVE)
Fig. 22 — VFD Shipping Bracket
(Unit with R Compressor Shown)
a23-1664
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