Moisture And Liquid Indicator; Adjust Regulating Valves; Dual Pressurestat Settings - Carrier 50AH024 Installation, Start-Up And Service Instructions Manual

1
50 B
INSTALLATION
Carrier
BA,BB,BC024
18. MOISTURE AND LIQUID INDICATOR
The moisture and liquid indicator must be full of
liquid refrigerant to properly indicate the moisture
content of the refrigerant. Operate the system at
least 30 minutes before attempting to determine the
moisture reading.
19. ADJUST REGULATING VALVES (IF USED)
(WATER-COOLED UNITS)
1. Consult the engineering survey to determine the
design condensing temperature and the water
shutoff condensing temperature used in selecting
the valve size. The shutoff point should be 90 F
(170.1 psig) or below.
2. Install a pressure gauge in the discharge service
valve and operate the unit to obtain a gauge
reading.
3. Temporarily adjust the valve until the condensing
temperature indicated by the gauge reading is 5
to 10 degrees (15 to 25 psig) below the design
condensing temperature.
4. Shut off the unit and observe the gauge pressure
at the instant the water flow into the open sump
stops.
5. Readjust the valve until it shuts off at the correct
shut off condensing temperature. At this setting,
the valve will hold the desired condensing tem¬
perature when maximum design conditions are
reached.
20. DUAL PRESSURESTAT SETTINGS
The 50BA and BC024 unit pressuxestats are factory
set to open at 280 -f 5 psig with a differential of 100
-t 15 psig on the high side. The low side is set to
cut-out at 46 -t 5 psig and cut in at 76 ± 5 psig.
The 50BB024 unit pressurestats are factory set to
open at 364 + 5 psig with a differential of 100 15
psig on the high side. The low side is set to cut-out
at 46 -t 5 psig and cut in at 76 -t 5 psig.
21. WIRING
All wiring should comply with local and National
Electric Code Requirements. Units are wired at the
factory for electrical characteristics shown on name¬
plate. Check nameplate electrical characteristics of
the unit with the available power supply. Power at the
unit must be within 10% of rated voltage, and the
phase voltages must be balanced within 3%. Contact
the power company for correction of line voltage that
is (1) not within 10% of standard, or (2) unbalanced.
OPERATION OF THE UNIT ON IMPROPER LINE
VOLTAGE OR WITH PHASES UNBALANCED MAY BE
CONSIDERED ABUSE AND IS NOT COVERED BY THE
CARRIER WARRANTY.
Provide separate fused disconnect switches of ade¬
quate size to handle the starting currents in the power
supply. Locate these switches within sight of the
unit. Proper wire and fuse sizes are given in Table
9. Use of undersized wire may cause nuisance
tripping, accentuated voltage unbalance and gener¬
ally unsatisfactory operation and unit life.
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FIG. 21 - LEFT END OF UNIT SHOWING
ELECTRICAL PANEL (COVER REMOVED)
The following recommended conduit sizes are for
field wiring power supply from the disconnect switch
to the motor contactor.
TABLE 8 - RECOMMENDED CONDUIT SIZES
Unit Electrical
Characteristics
Each Compressor Fan Motor
WC & C'less
WC
C'less
208/220-3-60
3/4" 1"
1/2"
220-2-60
1-1/4" 1-1/4" 1/2"
440-3-60 1/2" 3/4" 1/2"
550-3-60 1/2" 1/2" 1/2"
220-3-50 3/4" 1" 1/2"
380-3-50 1/2"
3/4"
1/2"
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