Carrier HERMETIC SCREW LIQUID CHILLERS 23 XL - Manual (Page 25)

INSTALL VENT PIPING TO RELIEF DEVICES — The
23XL chiller is factory equipped with relief devices on the
cooler and condenser shells. Refer to Fig. 26 and Table 7.
Vent relief devices to the outdoors in accordance with ANSI/
ASHRAE-15 (latest addition) Safety Code for Mechanical
Refrigeration and all other applicable codes.
To ensure relief valve serviceability and to fulfill
ASHRAE 15, latest edition, 3-way valves and redundant re-
lief valves are installed. See Fig. 26. Only one half of the
total number of relief valves listed in Table 7 are in service
at any time.
Refrigerant discharged into confined spaces can dis-
place oxygen and cause asphyxiation.
1. If relief devices are manifolded, the cross-sectional area
of the relief pipe must at least equal the sum of the areas
required for individual relief pipes.
2. Provide a pipe plug near outlet side of each relief device
for leak testing. Provide pipe fittings that allow vent pip-
ing to be disconnected periodically for inspection of valve
mechanism.
3. Piping to relief devices must not apply stress to the
device. Adequately support piping. A length of flexible
tubing or piping near the device is essential on spring-
isolated machines.
4. Cover the outdoor vent with a rain cap and place a
condensation drain at the low point in the vent piping to
prevent water build-up on the atmospheric side of the
relief device.
Make Electrical Connections — Field wiring must
be installed in accordance with job wiring diagrams and all
applicable electrical codes.
Do not run 120-v wiring into the control center. The
control center should only be used for additional extra
low-voltage wiring (50 v maximum).
Wiring diagrams in this publication (Fig. 27-31) are for
reference only and are not intended for use during actual
installation; follow job specific wiring diagrams.
Table 7 — Relief Device Locations
FRAME
SIZE
LOCATION
Cooler Condenser
Oil
Separator
Storage
Tank
(Optional)
Qty
Size
(in.)
Qty
Size
(in.)
Qty
Size
(in.)
Qty
Size
(in.)
1 or 2 1
3 ⁄ 4
FPT
2
3 ⁄ 4
FPT
1*
1 ⁄ 2
FL
2
1
FPT
4 1
1
FPT
2
1 1 ⁄
4
FPT
2*
3 ⁄
4
FPT
2
1
FPT
LEGEND
FPT — Female Pipe Thread
FL
— Flare
*Relief valve is only available when an optional (factory installed) or
accessory (field installed) refrigerant isolation package is used.
Do not attempt to start compressor or apply test voltage
of any kind while machine is under dehydration vacuum.
Motor insulation breakdown and serious damage may
result.
OIL RETURN
LINE
CONNECTION
CONDENSER
WATER
CONNECTIONS
REFRIGERANT
INLET VALVE
VENT VALVE
PUMPOUT
CONTROL BOX
(WIRING BY
CONTRACTOR)
(FIELD
INSTALLED)
Fig. 25 — Pumpout Unit
NOTE: The relief valve tree is available on all condens-
ers. It is also applicable to Frame 4 machines with
accessory isolation packages.
Fig. 26 — Typical 23XL Relief Valve Tree
25