Preparation; Operating The Optional Pumpout Unit; Positive Pressure Chillers With Storage Tanks - Carrier AquaEdge 19XRV series Operation, Maintenance And Installation Manual

PUMPOUT AND REFRIGERANT
TRANSFER PROCEDURES
The 19XRV chiller may come equipped
Preparation —
with an optional pumpout storage tank, pumpout system, or
pumpout compressor. The refrigerant can be pumped for ser-
vice work to either the chiller compressor vessel or chiller con-
denser vessel by using the optional pumpout system. If a
pumpout storage tank is supplied, the refrigerant can be iso-
lated in the storage tank. The following procedures describe
how to transfer refrigerant from vessel to vessel and perform
chiller evacuations.
CAUTION
Always run the chiller cooler and condenser water pumps
and always charge or transfer refrigerant as a gas when the
chiller pressure is less than 35 psig (241 kPa). Below these
pressures, liquid refrigerant flashes into gas, resulting in
extremely low temperatures in the cooler/condenser tubes
and possibly causing tube freeze-up.
WARNING
During transfer of refrigerant into and out of the optional
storage tank, carefully monitor the storage tank level gage.
Do not fill the tank more than 90% of capacity to allow for
refrigerant expansion. Overfilling may result in damage to
the tank or personal injury.
CAUTION
Do not mix refrigerants from chillers that use different
compressor oils. Compressor damage can result.
Operating the Optional Pumpout Unit —
should be visible in the pumpout unit compressor sight glass
Oil
Fig. 48 — Pumpout Unit Wiring Schematic
84
under all operating conditions and during shutdown. If oil is
low, add oil as described under Optional Pumpout System
Maintenance section, page 92. The pumpout unit control
wiring schematic is detailed in Fig. 48.
To read refrigerant pressures during pumpout or leak testing:
1. The ICVC display on the chiller control panel is suitable
for determining refrigerant-side pressures and low (soft)
vacuum. To assure the desired range and accuracy when
measuring evacuation and dehydration, use a quality
vacuum indicator or manometer. This can be placed on
the Schrader connections on each vessel (Fig. 12) by
removing the pressure transducer.
2. To determine pumpout storage tank pressure, a 30 in. Hg
vacuum -0-400 psi (-101-0-2769 kPa) gage is attached to
the storage tank.
3. Refer to Fig. 35, 36, and 49 for valve locations and
numbers.
CAUTION
Transfer, addition, or removal of refrigerant in spring-
isolated chillers may place severe stress on external piping
if springs have not been blocked in both up and down
directions.
POSITIVE PRESSURE CHILLERS WITH STORAGE
TANKS — In the Valve/Condition tables that accompany these
instructions, the letter "C" indicates a closed valve. Figures 35
and 36 show the locations of the valves.
CAUTION
Always run chiller cooler and condenser water pumps and
always charge or transfer refrigerant as a gas when chiller
vessel pressure is less than 35 psig (241 kPa). Below these
pressures, liquid refrigerant flashes into gas, resulting in
extremely low temperatures in the cooler/condenser tubes
and possibly causing tube freeze-up.
C
FU
GND — Ground
HTR — Heater
MTR — Motor
NC
OL
SS
LEGEND
— Contactor
— Fuse
— Normally Closed
— Overload
— Selector Switch
a19-2437