Inhibitor Reclaim System; Motor Cooling System; Vfd Cooling System; Vfd - Carrier AquaEdge 19DV series Start-Up, Operation And Maintenance Instructions Manual

STRAINER
ACTUATOR AND
3-WAY VALVE
PUMP
SUCTION
Inhibitor Reclaim System —
system moves inhibitor from evaporator and returns it to the
first stage suction inlet which allows it to be mixed in the sys-
tem since it has a tendency to have higher concentration in the
evaporator compared with the rest of the system. The reclaim is
powered by an eductor driven by the gas pressure difference
between first stage suction and discharge of second stage.
Motor Cooling System —
uid refrigerant taken from the bottom of the high side condenser
float chamber. Refrigerant flow is maintained by the pressure
differential that exists due to compressor operation. After the re-
frigerant flows past an isolation valve, an in-line filter drier, and
a sight glass/moisture indicator, it is directed over the motor by
spray nozzles. The refrigerant collects in the bottom of the mo-
tor casing and is then drained back into the cooler through the
motor refrigerant drain line. The motor is protected by tempera-
ture thermistors embedded in the stator windings. An increase
in motor winding temperature past the motor override set point
overrides the temperature capacity control to hold, and if the
motor temperature exceeds 10°F (5.5°C) above this set point,
the controls close the inlet guide vanes. If the temperature rises
above 122°F (50°C), the compressor shuts down. See Fig. 6.
VFD Cooling System —
sealed from the atmosphere to protect electronics from out-
side contaminants. Refrigerant is routed through a coil in
the VFD enclosure to regulate enclosure temperature while
still maintaining a temperature high enough to prevent con-
densation. VFD cooling line is branched off the motor cool-
ing supply. The refrigerant is then drained back into the
cooler through the motor/VFD drain line. Rectifier and in-
verter sections are air-cooled and protected by temperature
sensors embedded in the inverter. An increase in inverter
temperature past the override set point overrides the tem-
perature capacity control to hold, and if the temperature ex-
ceeds 10°F (5.5°C) above this set point, the controls close
the inlet guide vanes. If the temperature rises above 144°F
(80°C), the compressor shuts down. See Fig. 6.
All 19DV units are equipped with a VFD to oper-
VFD —
ate the centrifugal hermetic compressor motor. The VFD
ACTUATOR
PUMP
DISCHARGE
Fig. 5 — Refrigerant Lubrication Assembly
The inhibitor reclaim
The motor is cooled by liq-
The VFD enclosure
REFRIGERANT
PUMP
FROM
HIGH SIDE
FLOAT
CHAMBER
and control panel are the main field wiring interfaces for the
installing contractor. The VFD and control panel are mount-
ed on the chiller. See Manufacturer VFD specific informa-
tion and VFD schematics.
VFD model 32VS is designed to operate in an ambient
range of up to 104°F (40°C). The drive has two circuit boards.
The Digital Control Interface Board (DCIB) controls the
fans for cooling operation, IGBTs, measures three phase
line current, controls temperature input and cooling sole-
noid, controls outputs for pilot relays, and controls SAIA
communication.
The High Voltage Interface Board (HVIB) steps down in-
coming voltage to 24 VAC and sends this to the DCIB for mon-
itoring. The HVIB measures DC Bus voltage, controls the pre-
charge circuit, and controls SCR gating. It contains watchdog
LED to confirm DC Bus potential is depleted.
Should the drive need to be removed the 4 lifting lugs
should be utilized. See Fig. 7. 32VS 850A weight is approxi-
mately 1500 lbs. The drive is compatible with the Network
Service Tool V (NSTV).
Purge System —
condenser. See Fig. 8. It has two gas inlets coming from con-
is
denser and compressor. When chiller is running, the condenser
line is active/open and non-condensable gas will pulled out
from condenser and when chiller is idle the compressor line is
active and non-condensables are pulled out from compressor
volute. This is implemented due to non-condensable gas densi-
ty being less than refrigerant and therefore it will accumulate at
the highest point when chiller is not running.
In the purge tank the purge gas is cooled by a separate in-
tegral R-134a cooling system. The cooling system consists
of an compressor, an air cooled condenser coil, an expan-
sion valve, and a cooling coil in purge tank. Cooling the
purge gas results in condensation of R-1233zd(E) vapor as it
touches the coil resulting in a vacuum which the result that
more refrigerant is pushed to the coil. As the purge tank fills
up with refrigerant it will be drained through the purge drain
to the refrigerant pump assembly. See Fig. 9.
9
FROM EVAPORATOR
TO COMPRESSOR/
MOTOR BEARINGS
FILTER
The purge system is located under the