Carrier 30GB Air Conditioner User Manual

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High-capacity
liquid chillers
with energy-saving *
multiple-step capacity
control a
Carrier
The 30GB chillers provide multiple unit
capacity with single-package economy
Carrier’s 30GB units deliver 150, 175 or 200 tons of liquid
chilling capacity in a single enclosure. Compact size allows
faster rigging, installation and setup on the ground or on the
roof. Units arrive assembled and fully charged with R-22. A
simple hookup to power supply and chilled water lines
completes the installation.
The 30GB line saves operating costs with precise multiple
step capacity control. Either 6, 7 or 8 steps of control,
depending on the unit, allows load handling to 12-1/2% of
total capacity Condenser coils are circuited for maximum
subcooling, increasing unit capacity 1% for each 2 degrees
of subcooling with no increase in power input or need for
larger, costlier compressors. Multiple condenser fans cycle
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automatically to maintain positive head pressure for low
ambient operation down to 0°F without additional controls
to purchase!
The 30GB chillers perform reliably on the job, too. Com-
pressors are mounted on spring-isolated rails to minimize
vibration, eliminating the need for external isolation. All
controls and factory wiring are protected within weather-
resistant, galvanized steel enclosures. Fan guards are PVC-
coated steel wire for weather resistance.
Put Carrier's high capacity liquid chillers to work on your
large commercial job. The cost-saving advantages of fast
installation, controlled capacity operation, and low mainten-
ance really add up to superior performance.
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The Carrier 30GB chillers offer more
features for more cost-saving flexibility
Cooler freeze-up protection
Each unit is protected against cooler
freeze-up by 2 methods. A low-water
temperature safety thermostat stops
the unit automatically if water tempera-
ture drops below 36 F. By the second
method, factory-installed heaters pro-
tect the cooler from the effects of sub-
freezing ambient temperatures. These
heaters are located around the shell, be-
tween the shell and a thick layer of
closed-cell insulation; they are ener-
gized whenever the chilled water flow
stops.
Compressor crankcase heaters
Each compressor has an electric heater
that operates only during periods of
compressor shutdown to assure proper
lubrication by minimizing refrigerant
dilution of oil.
Easy access to components
All electrical components are acces-
sible thru removable service panels.
Cooler and compressor are protected
by removable steel wire guards. Carrier
also provides a handy convenience out-
let (115v) for connecting lights and
power tools.
Standby protection
Multiple compressor operation offers
system reliability in case of a malfunc-
tion or safety cutout. Dual, independent
refrigerant circuits maintain partial unit
capacity even if one circuit fails. This
backup protection can help prevent
costly damage in process cooling or
industrial applications.
Flow switch
Chilled water flow switch shuts down
the unit and energizes the cooler
heaters in case chilled water flow stops.
Units meet NEMA-MGI
motor standards
All compressor and fan motors meet
National Electrical Manufacturer’s
Association and U.S. government
standards.
CIRCUIT 1
14
High-pressure light
Low-pressure light
Discharge temperature light
Oll-pressure light
Valve, discharge pressure gage
Discharge pressure gage
Suction pressure gage
Valve, suction pressure gage
Control power light
3
CIRCUIT 2
980080 0000
Control power ON-OFF switch
Control circuit fuse
Reset button (control circuit)
Reset button (low water
temperature cutout)
Convenience outlet (115 volts)
Temperature controller
Lead/lag transfer switch
Demand limit light
CENTER OF GRAVITY = О;
RENOVABLE ACCESS Pa PANELS
CIRCUIT | CIRCUIT 2
FIELD POWER SUPPLY
(2 OR 3) 3" FPT STR
PIPE COUPLING STEEL WIRE 2]
Z FIELD SUPPLY, CONTROL
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“RENOVABLE. ACCESS PANEL - В
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Physical data (60-Hz)
nn UNIT 3068. o : - 150. i и 475 on {0 2990 20
—— APPROX OPER WT (Ib) MO _ 1 14,600 asi LL
_ REFRIGERANT CHARGE, R- 22 (Ib) BN 230/ckt о В 230/ ск: do 230/ckt —
“ COMPRESSORS (Type. .Rpm) | Reciprocating, Semi- Hermetic 1750
обе No.) Circuit 1 | (3) 6275 | . (4) F275 (4) F275
| (No. ) Circuit 2 (3) F275 (3) F275 (4) F275
a Cap. ( Control Steps | N о 6 or у a a g 7
Circuit 1_ © BO Ш 57 RE 50 I
о ее. cote es or - mans is + эн eee res sms ces et PR - pue = - ru 8 4m ww man MONO DEMAND O LAMSON —
CoP Circuit 2° 07 50 A so
Minimum Step Capacity (%) 167 | 43 11 = 125
CONDENSER FANS 3-Blade Propeller, Direct Drive
No. . .Diameter (in ) 12 30
Rpm. .Total Kw 1140 .186
Total Airflow (cfm) } 17,600 ns
"CONDENSER COILS 135 Fins/in 1/2-in OD Copper Tube
Condenser | Lead | Lag Lead { Lag Ш Lead I lag
No. Rows -C*t1 A A AA a Aa
Face Area _Ckt 1 605 | 85 605 605 | 605 |... 605
(safe) = Ckt2 605 | 605 805 1 605 | 605 | 605
COOLER, 10HA400504 | One Direct Expansion Shell and Tube
No. Refrigerant Circuits 2
Net Water Volume (gal ) 60 2 (Includes nozzles)
Maximum Working Pressure (psig) _ Refrigerant Side 235, Water Side: 150
— WATER CONNECTIONS (in) Ш Ва О
Inlet and Outlet 6 150-1b ASA Flat Face Flange
Drain | (3/4 F
30GB150-200
TOP VIEW — FAN AND COMPRESSOR LOCATIONS; FAN OPERATION
COOLER SIDE
MAIN AUXILLIARY
CONTROL CONTROL
BOX END BOX END
COMPRESSOR SIDE
CIRCUIT | CIRCUIT 2
175
30GB 1200 —e | 3 5 7 8 6 4 2 le—— 306B200
3068150 — — — > | 3 5 6 4 2 *— 43068150
30GBI7 5
~~ РАМСОМТАСТОВ №. "| CONTROLS FAN NO. CONTROLLED BY:
© FC1 о 1 ALWAYS RUNS WITH COMPR NO 1
CIRCUIT FC3 | 3 0 TEMPERATURE & CHR5 (Ambient over 70 F)
1 FC5 | TA PRESSURE. Closes 260, opens 160 psig
FC7 | 589 TEMPERATURE: Closes at 70 F
A Оо ALWAYS RUNS WITH COMPR NO 2
{ CIRCUIT FC4 4 TEMPERATURE & CHR6 (Ambient over 70 F)
“а 2 FC6 DE PRESSURE: Closes at 260 psig, opens 160 psig
FC8 | 5810 TEMPERATURE: Closes at 70 F
S election procedure II Select unit to provide cooling load capacity.
(with example) Enter Performance Ratings table at 95 F CEAT and 45 F
LCWT. Under Cap., 196.7 tons is nearest to and greater
than the given cooling load (190 tons). Read unit selection e
I Determine job requirements. and performance data directly from table:
Given: 0 A 30GB200
Cooling Load .............eeeneococorer. 190 Tons Capacity (Cap.).........ee.r.eeeeoovooo 196.7 Tons
Leaving Chilled Water Temperature (LCWT)....45F Saturated Discharge Temp (SDT) ........... 1309 F
Chilled Water System A T..........e.e.ereonoo 10 F Compressor Power Input (Kw). ........... 246.3 Kw
Cooler Fouling Factor ........ _.e.eoeeecreoro 0.0005 Cooler Flow Rate (Gpm) ................. 471.0 gpm
Condenser Entering Air Temperature (CEAT) ...95 F Cooler Pressure Drop (PD). ............ 12.5 ft water
Performance data
Ratings Cap. — Capacity
The following ratings tables are based on 10 F chilled water rise, 0.0005 fouling factor in cooler, and Kw — Comer input Motor
Refrigerant 22. Ratings in boldface type are in accordance with ARI Standard 590-76. Thecondi- LcwTt — Leaving Chilled
tions are 95F Condenser Entering Air Temperature (dry-bulb), 44 F Leaving Chilled Water Water Temp
Temperature. PD — Pressure Drop
(ft water)
PERFORMANCE RATINGS (10F Chilled Water Rise) SDT — Sat Disch Temp
ul CONDENSER ENTERING AIR TEMPERA ©
Ds 95 os
| Cooler inmi Cooler
Ser Compr Flow Data ¿<< Ser Compr | Flow Data
(F) "| брт | РБ 8 (F) | “МО | брт | РО
11147 | 1647 | 3657 76 1234 | 1735 13397 | 66
11174 | 1935 | 4144 | 97 1259 | 203.2 13857 | 85
11192, 2208 | 456 9 | 117 1276 | 2312 4251 1102
1159 | 168.7 3812 83% 11245 1778 13546 | 72
1187 | 1984 | 4321 | 105 ! 1271 | 2083 14022 92
120.5 | 226.3 | 475.7 12.7 £ 128.9 | 237.2 | 4432 111.1.
1171 1726 3971 89€ 125.7 182.2 3698 78
1199 | 2033 ; 4500 114 % 128.4 | 213.6 419.8 | 9.9
121.8 | 2319 | 494.9] 137 | 130.2 | 243.3 4616 12.0
1177 | 1746 4051 93 1262 | 184.4 | 3775 . 81
1206 | 2067 4590/118! 1290 | 2162 | 427 9 |103
1225 2347 5045 | 142 | 1309 | 2463 4710 1125
1183 | 1767 | 4133] 97% 1268 | 186.6 3854 | 84
1212 | 2082 | 467 9 | 123 1297 2189 4367 108
123.2 | 2376 | 5142 148 | 131.5 2493 | 4803 129
1195 | 1808 | 4298 104 1280 | 1910 4010 91
122 6 | 2133 | 486 7 | 133 | 1310 | 2244 | 4546 |116
124 6 | 2434 | 5341 | 159 € 132 9 | 255 6 | 4995 | 13.9 —
CONDENSER ENTERING AIR TEMPERA о
Cooler Cooler
Сар. | SDT Compr Flow Data : SA Compr Flow Data
(Fons) | (1 1 6 1 Gpm | PDS | “| брт | PD
1314 11321 1815 | 3142 57% 1407 1884 | 2885 | 48
1 1491 [1344 | 2118 | 3564 | 73€ 1430 | 2195 | 3280 | 62
1 164.7 [136.1 | 2406 | 393.7 | 88 © | 1445 | 2488 | 3623 | 75
1372 .1332| 1861 | 3282| 62 141.8 | 1935 3021 5.3
1 155.7 |135 6 | 2174 : 3724) 79 1441 | 2256 3433 67
171.9 | 137.3 2470 411.1} 9.6 ; 1457 | 2557 | 3789 | 82
1143.2 1343 1908 | 3428 6.7 11429 1987 13160 | 57
11624 1368 2230 | 3887 | 8.6 1453 | 2317 3589 | 74
! 179.3 | 138.6 | 2537 | 429 1 | 104 1470 | 2627 {3960 | 89 _
146.2 134.8 1932 | 3501! 70 14347 2012 13228 60
1658 1374 2259 3970 8.9 1459 | 2348 ! 3668 | 77
183.0 | 139.3 | 256.9 | 438.1 | 108 ii 1476 | 266.2 | 4046 | 93 _
1493 | 1354 | 1956 | 35676] 73 ¢ 1440 | 2038 | 3299 | 62
169.3 | 13811 2289 | 4056] 93 Ё 146.5 | 2378 | 374.7 | 80
186 7 1399 2603 | 447.2] 113 § 1482 | 269.8 | 4133 | 97
1556 ; 1366 ; 2005 3728. 79 Ë 145.1: 209.1. 3444: 68
176.4 1394 234.7 4227, 101 147.8 | 244.1 ! 3910 | 87
194 3 | 141 2 | 2670 | 465 7 | 12 2 1495 | 2769 | 4309 | 10,5
PRESSURE DROP (FT OF WATER)
0
OOOO OO MMONLCO MDL HE TONAL 00 DF TE UAM JUDO
TOTAL COOLER PRESSURE DROP
10HA400504 Cooler
100
80 AA = - = .. = <. = Киа . = a - qe
m0 Fée
вс EZ AT
30
25 e = x =
20
100
UNIT et ng aos -|COMERESSORS!. _ _ FANMOTORS; __|CONTROLS
о Моне т |
Do Оф 1 o © we ан жет | о г уре * *
na РАДИО. | a RLA LRA {MTA : Total FLA | MTA Hp
30G8 : Model Name- | Supplied” | o MCA ¡MFA ICF | = (ea) | (CB) Kw PA (ea) | (FCB) | (NEC) Kw
4 1 plate | Min {Max | Start 5 _ | |
5001 208-2301 187 1253 | XL 767 1000 1136 iis 110 | 506 | 154 7 186 | 3 66 | 74 194 027
“150. ; 600 © 460 414 |508 XL 362 450 ; 550 253 | 73 [186 . 3 4 | 28 175 027
4100 575 | 518 _| 632 | XL 1 310 400 . 430 J 4 1176 | 63 18.6 | 3 22 1175 027
15.500 1208-230 | 187 253 | XL | 877 |1000 |1246 | 10 506 |154 ¡186 | 3 5 6” 74 ¡194 | 027
175.1 690 | 460 ; 414 508 | XL 414 500 | 602 32 253 73 {186 | 3 + 30 28 | 1.75 | 027
Li. 190: 575 1518 632 | XL | 355 | 400 | 475 | 4 0 1176 | 63 186 3 |24 | 22 |. 0.27
1 500 | 208-230 187 1253 | XL | 987 | 1200 11356 E 506 :154 186 | 3 | 66 | 74 | 194 | 027
“200 ; 600 | 460 | 414 508 XL | 466 | 600 A 52 |253 | 73 186 3 30 28 175 | 0.27
4.300 | 575 | 518 632 | XL | 400 450 | 520 45 176 | 63 186 13 | 24 | 22 175 | 027
CB — Circuit Breaker MTA — Must Trip Amps (Circuit Breaker)
FCB — Fan Circuit Breaker NEC — National Electrical Code
FLA — Full Load Amps (Fan Motors) Ph — Phase
Hp — Horsepower RLA — Rated Load Amps (Compressors)
ICF — Maximum Instantaneous Current Flow during starting (the XL — Across-the-Line
point in the starting sequence where the sum of the LRA for
the starting compressor, plus the total RLA for all running
compressors, plus the total FLA for all running fan motors *Units are suitable for use on electrical systems where voltage
\ is maximum) supplied to the unit terminals is not below or above the listed
+ Kw — Total condenser fan motor power input minimum and maximum limits
LRA — Locked Rotor Amps T30GB150 has 6 compressors; 30GB175 has 7 compressors;
MCA — Minimum Circuit Amps (for wire sizing) Complies with NEC 30GB200 has 8 compressors
Section 430-24 tEach unit has 12 fans
MFA — Maximum Fuse Amps (Maximum overcurrent protective **Each unit has 2 fan circuit breakers; 6 fans are protected by each
device amps)
200 250 300
400 500 600.
COOLER WATER FLOW (GPM)
Electrical data (60-Hz)
HATE NORRATH
Зимние
COE EHH rT Ha erat
ос
MORON Ii кони
1000
900
HL GUNS OOOO Ce Ha HEMER DOOR Bl
FCB
Electrical data (60-Hz) (cont)
General electrical notes
1. The 115-1-60 control circuit power must be supplied from
a separate source, thru a field-supplied 30-amp fused
disconnect.
2. Crankcase and cooler heaters are wired into the control
circuit so they are always operable as long as the control
circuit power supply disconnect is on, even if any safety
device is open or the unit ON-OFF switch is off.
3. Heaters are wired ahead of the control circuit fuse; thus,
they are protected by the 30-amp overcurrent protective
device in the control circuit power supply.
Start-up sequence
The control power switch is off and all crankcase heaters
and cooler heaters are energized.
The chilled water pump (CWP) must be turned on before
the control circuit can be energized.
When the chilled water begins circulating, the flow switch
(CWFS) closes. The cooler heater cable (CHC) is de-
energized and the flow relay is energized.
When the control circuit switch is turned on, the 115-volt
control circuit and parts of the 24-volt circuit are energized.
The SC cycles back to the completely unloaded position
and unit start-up can proceed.
4 All units have single-point power connection to simplify
field-power wiring.
5. The 208-230/3/60 units have 3 terminal blocks and
require 9 parallel conductors from the disconnect
6 The 460 and 575/3/60 units have 2 terminal blocks and
require 6 parallel conductors from the disconnect.
7 Maximum incoming wire size for each terminal block is
500 MCM.
8 The 208-230-volt 30GB200 units must have copper
main power conductors to meet NEC requirements.
Circuit no. 1 (start-up of lead compressor) — With the
temperature controller (TC) calling for cooling, SW1 in
the SC makes and no. 1 condenser fan starts. If the ambient
is over 70 F, fans no. 5 and 9 start; fans no. 7 and 11 start
after compressor no. 1 starts and the discharge pressure
exceeds 260 psig.
Relay no. 1 (R1) and the rest of the 24-volt circuit are
energized. The start-up function continues as follows (refer
to LEGEND for identification of components):
LEGEND
CH — Crankcase Heater DTR — Discharge Temperature Relay OPR Oil-Pressure Relay
CHC — Cooler Heater Cable FLR — Flow Relay OPS Oil-Pressure Switch
CHR — Crankcase Heater Relay HPR — High-Pressure Relay R Relay -
CLO — Compressor Lockout HPS — High-Pressure Switch sc Step Controller
CR — Control Relay LLS — Liquid Line Solenoid Valve SW Switch
CWFS — Chilled Water Flow Switch LOR — Lock-Out Relay TC Temperature Controller
CWP — Chilled Water Pump LPR — Low-Pressure Relay TD Time Delay
DGT — Discharge Gas Thermostat LPS — Low-Pressure Switch
®
ery COMPRESSOR ee
Cr SHUTS NOT a =
ЗУМОМ ‘OFF. RI TE = ; ; ия est & OPS? Les Is
- CLOSED.
(e
Circuit no. 2 (start-up of lead compressor) Circuit no. 2 shuts down
4 As the TC continues to call for cooling, SW2 in the SC As cooling load continues to decrease:
makes. As in circuit no. 1, circuit no. 2 is energized and
compressor no 2 starts thru a sequence of electrical
functions which are a duplication of circuit no. 1. Also, : 14 :
condenser fans no 2, 6, 10, 8 and 12 start | SCBREAKS
With the lead compressor in each circuit running, and
the TC still calling for cooling, the start-up continues:
COMPRESSOR. | al Va Ma En at.
NO. 3 STARTS.
e TT a a Ta Tae a aa AT aa Tata a a a
Dn us opens a uo Ш
When compressor no. 5 starts, condenser fan no. 3 EET OR = UA ;
starts, if ambient is over 70F; when compressor no. 6
starts, condenser fan no 4 starts, if ambient is over 70F. 1
The unit is now running at full load with all compressoss FT TT TT me
and fans operating. compressor NO. 2 STOPS НЕ
Operation as load is decreased
As the demand for cooling decreases, the unit shuts down Circuit no. 1 shuts down
thru the following steps: Cooling load continues to decrease:
be MEN LG COMPRESSOR |
Sn | ENERGIZED. |) SC BREAKS: [7H “NO. © STOPS-
5 Le | MON COMPRESSOR
ENERGIZED BEET ome “scsreacs TP} No.7 STOPS
y The unit is now cycled off, ready to restart under TC
В ВЕ control when additional cooling is needed.
© CONTINUES UNTIL 5
COMPRESSOR NO. 3 STOPS
©
a When compressor no. 6 stops, condenser fan no. 4 stops
and when compressor no. 5 stops, condenser fan no 3
stops.
Application data
Unit performance with external static on
condenser fans
Every effort should be made to install unit where the
condenser airflow above the unit is unrestricted. If this is
not possible, unit performance is affected and data must be
corrected as follows:
EXTERNAL STATIC CORRECTION FACTORS
EXTERNAL | % СЕМ CAPACITY | — KW
‘ DECREASE | MULTIPLIER | MULTIPLIER
(in. wg) | |
0.10 85 0 986 1014
T7020 |! 175 0 968 | 1.031
Cooler fouling factor correction
FOULING CAPACITY KW
FACTOR MULTIPLIER MULTIPLIER
_... 00005 | ___ 100 110 10
9.001 „097 _ 09% __—__
0.002 091 0 94
Corrected Cap. = Rated Cap. x Cap. Corr Factor
Corrected Kw = Rated Kw x Kw Corr Factor
_ Corrected Cap. (tons) x 24
À T (F)
Corrected Gpm
Low-ambient operation — The minimum ambient tem-
perature at which the unit will start and build up head
pressure on the first and second steps of capacity 15 20 Е.
After operation is established, the minimum operating tem-
perature is approximately 0°F.
Field-installed chilled water piping may be protected at
lower ambients by wrapping with field-supplied heating
cable and covered with 2-in. thick closed cell insulation.
It is strongly recommended that ethylene glycol be used
in installations where sub-freezing temperatures are
expected.
Unit performance data must be corrected as shown in
the following example:
I Determine concentration of ethylene glycol re-
quired to protect system to -10F (at zero flow).
Given:
Unit .......e.ecreoaarororarocacrorecrao 30GB200
Condenser Entering Air Temperature (CEAT) ..95 F
Leaving Chilled Water Temperature (LCWT) ...45 F
Chilled Water System A T.........e.eeeeese.. 10 Е
Capacity ..........eseorcorerererere.. 196.7 Tons
Chilled Water Flow Rate ................ 471.0 gpm
Cooler Pressure Огор ................ 12.5 ft water
Compressor Power Input............_.... 246.3 Kw
From curve, read 40% concentration is required for
solution crystallization at -10F.
II Correct unit capacity.
From curve, read 0.983 capacity correction at 40%
concentration.
Corrected Capacity
0.983 x Given Capacity
0.983 x 196 7 Tons
193.4 Tons
il
10
II Correct chilled water flow rate.
From curve, read 1.097 gpm correction at 40%
concentration.
Chilled Water Flow _ Tons x 24 _ 193.4 x 24
(at corrected Cap.) AT a 10
= 464.2 gpm
Ethylene Glycol Flow = water flow x 1.097
(40% solution) = 464.2 x 1.097
= 509.2 gpm
IV Correct cooler pressure drop.
From curve, read 1.185 cooler pressure drop correction
at 40% concentration. From cooler pressure drop curve,
for 509.2 gpm of water, pressure drop = 14.7 ft water.
PD for 40% ethylene glycol solution = 1.185 x 14.7 =
17.4 ft water.
V Reduction in compressor power input (Kw) is
insignificant.
ETHYLENE GLYCOL PERFORMANCE
CORRECTION FACTORS AND SOLUTION
CRYSTALLIZATION POINTS
1.20
1.15
i 10
CORRECTION FACTOR
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—20
TEMPERATURE (F)
+20
% CONCENTRATION (BY WEIGHT) ETHYLENE GLYCOL
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Guide specifications
Furnish and install factory-assembled, one-piece Carrier
30GB packaged air-cooled liquid chiller(s). Unit(s) shall
be completely factory charged with Refrigerant 22. All
factory wiring and piping shall be contained within the unit
enclosure. All electrical components shall be mounted in a
rain-tight enclosure. The exterior sheet metal shall be
galvanized steel, zinc phosphatized, with an electro-
statically applied, high solids polyester, baked enamel finish.
Capacity of unit(s) shall be not less than tons,
cooling gpm of water from F to F, air
entering the condenser at F. Cooling fouling factor
shall be . Unit power input shall not exceed kw.
Unit electrical power shall be volts, 3-phase, 60-Hz.
Unit shall be capable of operating within line voltage limits
of to volts. Control power shall be provided by
a separate 115-volt, single-phase, 60-Hz source.
Construction and ratings shall be in accordance with
ARI Standard 590-76 and shall comply with ANSI B9.1
Safety Code, National Electrical Code (NEC) and ASME
Code.
Each compressor shall be reciprocating, serviceable
hermetic type and shall have an automatically reversible oil
pump, complete with operating oil charge Compressors
shall be equipped with suction and discharge shut-off valves
and shall be mounted on spring-isolated rails. Motors shall
be cooled by suction gas passing around the windings and
shall have overtemperature protection Manual restart of
unit shall be required after motor stoppage due to thermal
overload. Each compressor shall be equipped with an
insert-type crankcase heater to minimize oil dilution during
shutdown periods
Each compressor motor shall be operated and protected
against overload by means of definite-purpose contactors
and calibrated, ambient-compensated, magnetic-trip circuit
breakers. The circuit breakers shall open all (3) phases in
the event of overload in any one phase and shall be manual
reset.
Cooler shall be covered by 2 layers of 3/4-in. closed cell,
vapor barrier, expanded polyvinyl chloride (PVC) insula-
tion, with a maximum “K” factor of 0.28. Heaters along the
shell, under the insulation, shall protect the cooler against
freeze-up.
11
Refrigerant circuit components shall include hot-gas
muffler; highside pressure relief device; liquid line shut-off
valve; replaceable-core filter-drier; moisture-indicating sight
glass; liquid line solenoid valve; maximum operating pres-
sure limiting thermal expansion valve.
Air-cooled condensers shall be circuited to provide sub-
cooling. Condensers shall be constructed of 1/2-in. OD
seamless copper tubes with mechanically-bonded alumi-
num fins, leak tested at 150 psig and pressure tested at
450 psig.
Condenser fans and motors — The condenser section
of each unit shall have direct-drive, propeller type fans, with
steel wire safety guards. Fan motors shall be 3-phase,
permanently lubricated and inherently protected with
corrosion-resistant fan shaft.
Head pressure control — Each unit shall be equipped
with a head pressure control system. Condenser fans shall
be cycled by a combination of discharge pressure and
ambient temperature to permit unit operation to 0°F out-
door ambient at full load.
Each unit shall contain an electrically operated multiple-
step capacity controller with a minimum of 6 steps of
capacity reduction (30GB150); the 30GB175 unit shall have
7 steps and the 30GB200 shall have 8 steps. Unit capacity
shall be controlled by starting and stopping compressors.
The unit can be field modified for use of hot gas bypass.
Controls shall be factory mounted and wired in a weather-
proof enclosure. It shall include a low-pressure switch for
each refrigerant circuit; an electronic ground current
sensing refrigerant circuit protection device for each com-
pressor; lead-lag switch; suction and discharge pressure
gages, with shut-off valves; chilled water safety thermostat;
field power and control circuit terminal blocks; compressor
motor and fan motor circuit breakers; motor contactors;
control relays; control circuit ON-OFF switch; energy
management system interface for demand-limit control. A
high-pressure switch shall be factory mounted on each
compressor; on the lead compressor in each circuit an oil-
pressure safety switch shall be factory mounted. A chilled
water flow switch shall be factory mounted on the chilled
water inlet nozzle.
Number One
Air Conditioning
Maker
© Division of à
Carrier Corporation
Carrier Parkway + Syracuse N'Y 13221
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book |2 Form 30GB-1P New PrintedinUS A 8-81 PC 111 CatalogNo 523-030
Tab |5c