Operation and Installation Manual
SCW Series
Central Chilling Stations
Important! Read Carefully Before Attempting to Install or Operate Equipment
Part No. A0551795 Bulletin No. SC3-635.1
Write down your unit serial number(s) ________________ ________________
here for future reference ________________ ________________
________________ ________________
________________ ________________
Sterling is committed
to a continuing program of product improvement.
Specifications, appearance, and dimensions described in this manual
are subject to change without notice.
© Copyright Sterling 2008
All rights reserved. Effective 4/11/2008
Part No. A0551795 Bulletin No. SC3-635.1
Page 2 of 77 SCW Series Central Chilling Stations
Safety Considerations
Sterling SCW Series central chilling stations are designed to
provide safe and reliable operation when installed and operated
within design specifications, following national and local safety
codes.
To avoid possible personnel injury or equipment damage when
installing, operating, or maintaining this equipment, use good
judgment and follow these safe practices:
; Only PROPERLY TRAINED personnel familiar with the
information within this manual should work on this equipment.
; Follow all local SAFETY CODES.
; Wear SAFETY GLASSES and WORK GLOVES.
; Disconnect and/or lock out power before servicing or
maintaining the chiller.
; Use care when LOADING, UNLOADING, RIGGING, or
MOVING this equipment.
; Operate this equipment within design specifications.
; OPEN, TAG, and LOCK ALL DISCONNECTS before
working on equipment. Sterling recommends following OSHA
Lock-Out/Tag-Out Standard 29 CFR 1910.147.
; Make sure the unit is properly GROUNDED before switching
power on.
; When welding or brazing in or around this equipment, be sure
VENTILATION is ADEQUATE. PROTECT adjacent
materials from flame or sparks by shielding with sheet metal.
An approved FIRE EXTINGUISHER should be close at hand
and ready for use if needed.
; Do not jump or bypass any electrical safety control.
; Do not restore power until all tools, test equipment, chiller and
related equipment have been removed.
SCW Series Central Chilling Stations Page 3 of 77
Table of Contents
1 General Information .................................................8
; 1-1 Introduction ....... 8
; 1-2 Necessary Documents 8
; 1-3 Models Covered 9
; 1-4 Standard Features 9
; 1-5 Available Options 10
2 Shipping Information .............................................16
; 2-1 Unpacking and Inspection 16
; 2-2 In the Event of Shipping Damages 16
; 2-3 If the Shipment is Not Complete 17
; 2-4 If the Shipment is Not Correct 17
; 2-5 Returns.............. 17
; 2-6 Uncrating Your New Chiller 18
3 Installation...............................................................20
; 3-1 Installation Location Considerations 20
; 3-2 Making Electrical Connections 20
; 3-3 Piping Considerations 22
; 3-4 Making Process Water Connections 22
; 3-5 Making Tank Piping Connections 23
; 3-6 Water Connection Sizing Considerations 24
; 3-7 Galvanic Corrosion Considerations 24
; 3-8 Water Treatment Considerations 24
; 3-9 Making Water-Cooled Condenser Connections 24
; 3-10 Installing the Remote Air-Cooled Condenser 25
; 3-11 Checking Motor Direction 26
4 Sequence Of Operation........................................277
; 4-1 Staging.............. 28
; 4-2 Alarms............... 28
; 4-3 Lead-Lag Compressors 28
; 4-4 Lead-Lag Pumps 28
; 4-5 Chilled Water Circuit 29
Page 4 of 77 SCW Series Central Chilling Stations
; 4-6 Refrigeration Circuit 29
; 4-7 Freezestat Control 29
; 4-8 High Pressure Cutout 31
; 4-9 Low Pressure Cutout 31
; 4-10 Flow Switch....... 31
; 4-11 Control Nipple ... 32
; 4-12 Control Probe.... 32
; 4-13 Chilled Water Manifold 32
; 4-14 Optional Condenser Water Manifold 32
5 Startup Checklists..................................................34
; 5-1 Introduction ....... 34
; 5-2 Water-Cooled SCW Series Startup Checklist 34
; 5-3 Water-Cooled SCW Series Startup 36
; 5-4 Remote Air-Cooled SCW Series Startup Checklist 37
; 5-5 Remote Air-Cooled SCW Series Startup 39
; 5-6 Determining Flow Rate 40
; 5-7 Shutdown.......... 40
6 Graphic Panel Devices...........................................41
; 6-1 Indicator Lights and Control Switches (MMI) 41
7 Using the Standard Touchscreen Interface.........43
; 7-1 Operator Interface Introduction (MMI) 43
; 7-2 Using the SCW Series Standard Operator Interface 44
; 7-3 Getting Started on the SCW Series Standard Operator Interface 45
; 7-4 Viewing and Operating Chiller Compressors 45
; 7-5 Viewing and Operating Chiller Pumps 45
; 7-6 Viewing Active Alarms and Handling Alarm Conditions 46
; 7-7 Viewing and Setting System Temperatures 46
8 Using the Advanced Touchscreen Interface........48
; 8-1 Touchscreen Interface Introduction (MMI) 48
; 8-2 Using the SCW Series Advanced Touchscreen Interface 49
; 8-3 Getting Started on the SCW Series Advanced Touchscreen Interface 50
; 8-4 Viewing and Operating Chiller Compressors 50
SCW Series Central Chilling Stations Page 5 of 77
8-5 Viewing and Operating Chiller Pumps .................55
; 8-6 Viewing Active Alarms and Handling Alarm Conditions 59
; 8-7 Viewing and Setting System Temperatures 61
9 Routine Maintenance .............................................64
; 9-1 Lubrication......... 64
; 9-2 Condenser Maintenance 64
; 9-3 Evaporator Maintenance 65
; 9-4 Pump Motor Seal 65
9-5 Makeup Valve..........................................................65
; 9-6 Recommended Pump Tank Spare Parts 65
; 9-7 Preventive Maintenance Service 66
10 Troubleshooting .....................................................68
I Index ........................................................................72
Page 6 of 77 SCW Series Central Chilling Stations
Charts and Figures
1
Typical Two-Circuit 60-195 Ton Water Cooled Chiller 11
2
Typical Two-Circuit 60-195 Ton Remote Air Cooled Chiller 13
3
Freezing Protection Curve 29
4
SCW Series Standard Control Panel 39
5
SCW Series Advanced Control Panel 40
6
SCW Series Standard Control Panel 44
7
SCW Series Advanced Control Panel 58
8
Main Menu Screen (Advanced Control Panel) 59
9
10
11
12
13
14
15
16
17
Chiller Status Screen (Advanced Control Panel) 61
Chiller Configuration Screen (Advanced Control Panel) 62
Compressor Run Time Display Screen (Advanced Control Panel) 64
Pump Status Screen 65
Pump Enables Screen 66
Pump Run Time Display Screen 68
Alarm Condition Screen 69
System Status Screen 71
Temperature Input Display Screen 72
SCW Series Central Chilling Stations Page 7 of 77
1 General Information
1-1 Introduction
Sterling SCW Series central water chilling stations are available in
water-cooled and remote air-cooled designs. They differ only in
the condensing media used. The SCW Series units are configured
with two independent circuits using multiple compressors for each
circuit. This manual lists information for these units.
SCW Series chilling stations may be configured with stainless steel
pump tanks for use as reservoirs for chilled water processes. These
dual-well models hold hot and cold water before and after it is
pumped through the chiller. Tanks have recirculation pump(s) to
send return water to the chiller and process pump(s) to pump
cooled water directly to process. Standby pumps may be utilized to
distribute pump service or to allow uninterrupted chiller operation
during pump maintenance.
Properly installed, operated, and maintained SCW Series chilling
stations provide many years of reliable operation. To get the most
satisfaction from your new chiller, read and follow the
instructions in this manual.
1-2 Necessary Documents
The following documents are necessary for the operation,
installation, and maintenance of Sterling SCW Series central
chillers. Additional copies are available from Sterling.
Familiarize the appropriate personnel with these documents:
; This manual.
; The schematic and connection diagram in the control
enclosure.
; Operation and installation manuals for accessories and options
selected by the customer.
; The Customer Parts List included in the information packet.
Page 8 of 77 SCW Series Central Chilling Stations
1-3 Models Covered
This manual provides operation, installation, and maintenance
instructions for the SCW Series central chilling stations.
Model numbers are listed on the serial tag. A model number
followed by Q indicates a specially constructed unit, and not all
information in this manual may apply. Make sure that you know
the model number, serial number, and operating voltage of your
chiller if you contact Sterling.
1-4 Standard Features
• Two independent refrigeration circuits
• High-efficiency screw compressors
• Stainless steel brazed plate (60 & 75) Shell & Tube (90 –
195) evaporators
• Cleanable shell and tube condensers (water-cooled models)
• Electronic expansion valve
• 2 remote single circuit condensers with variable speed lead
fans and fan cycling (air-cooled models)
• NEMA 12 electrical enclosure
• Mitsubishi FX2N PLC control with F930GOT touchscreen
interface.
• High and low refrigerant pressure safeties
• Touch-safe branch circuit fusing
• Evaporator water piping manifold (Condenser manifold
optional)
• R-134a refrigerant
• Digital low temperature freezestat
• Liquid line solenoid and shut-off valves
• Chilled water flow switches
• 1 year warranty on parts and labor
• 3 year warranty on controller
SCW Series Central Chilling Stations Page 9 of 77
1-5 Available Options
SCW Series central chillers are available with options to tailor the
unit to your requirements. Some are factory installed; some can be
retro-fitted in the field. Consult Sterling sales for more
information. Available SCW Series options include:
• Advanced control package including: Mitsubishi P2A PLC
control with A970GOT – color touchscreen interface; provides
control of up to nine additional chillers, cooling tower system,
water treatment system
• General Fault audible/visual alarm with elevated light stack
• Non-fused rotary thru-the-door disconnect switches
• Electrical operation available in 208, 460, and 575 volts,
60 Hz; 200, 380, and 415 volts, 50 Hz
• UL/CUL-listed electrical subpanel
• Water cooled condenser manifold
• Onsite startup
Standard Features on Remote Condensers
• Direct-drive 3-phase fan motors with ball bearings and internal
overload protection
• Electronic variable-speed control of lead fan and fan cycling
for constant condenser head pressure control
• Fans are 30” (76 cm) in diameter and have PVC-coated steel
fan guards; 1½ hp (1.12 kW) variable-speed fans are 26” (66
cm) in diameter
• Internal baffles between fan cells
• UL listed in the United States and Canada
• Patented floating tube coil to eliminate tube sheet leaks
• Copper tube condenser coils have corrugated aluminum fins
• Weather-proof control panel with factory-mounted door
interrupt switch
• High-efficiency condenser coil, designed for optimum
performance
• Aluminum housing provides corrosion protection for outdoor
applications
Page 10 of 77 SCW Series Central Chilling Stations
Model Number Nomeclature
SCW W 060
SCW – Screw Compressor Central Chiller
Condenser Type
R – Remote Air Cooled
W – Water Cooled
(Nominal Unit Size)
060 115
075 145
090 165
100 195
SCW Series Central Chilling Stations Page 11 of 77
Figure 1
Typical Two-Circuit 60-195 Ton Water Cooled Chiller
Model
Cooling Capacity (tons) @ 50°F LWTc
Capacity stages
EER (BTUH/W) 15.2 15.1 15.7 15.5
Nominal water flow (gpm)
Condenser connection (no manifold) Flange Conn. (in.) 2.5 3
Evaporator manifold connection Victaulic 3 4
Amp draw, nameplate
(460/3/60 V)f
Dimensions (in.)
Shipping weight (lbs) 3,266 3,512 4,336 4,982
Max operating weight (lbs.) 3,468 3,754 4,594 5,246
c Based on 50ºF (10ºC) chilled water supply temperature and 85ºF (29ºC) tower water.
d Based on 2.4 gpm per ton (9.1 lpm per 3.517 kW).
e Based on availability of 85ºF (29ºC) tower water at 25 psi (172.4 kPa/1.7 bars) minimum.
f Multiply 460/3/60 amperage by 2.0 for 208-230/3/60 amperages; multiply by 1.2 for 380/3/60 amperages; multiply by 0.8 for
575/3/60 amperages
Evaporatord 145 180 213 245
Condenserse 181 225 266 307
Water-cooled 112 130 138 170
Height 85 74
Width 100 115
Depth 45 72
60 75 90 100
60.4 74.9 88.8 102.2
SCWW-xxx
Infinite Unloading
Page 12 of 77 SCW Series Central Chilling Stations
SCWW-xxx Model
115 145 165 195
Cooling Capacity (tons) @ 50°F LWTc 116.3 146.0 166.3 193.1
Capacity stages
Infinite Unloading
EER (BTUH/W) 15.5 16.2 15.9 16.2
Nominal water flow (gpm)
Evaporatord 279 350 399 463
Condenserse 349 438 499 579
Condenser connection (no manifold) Flange Conn. (in.) 3 4
Evaporator manifold connection Victaulic 4 6
Amp draw, nameplate
(460/3/60 V)
f
Water-cooled 216 250 282 316
Height 77 81
Dimensions (in.)
Width 124 137
Depth 72 75
Shipping weight (lbs) 5,298 8,844 9,376 9,580
Max operating weight (lbs.) 5,584 9,428 10,102 10,364
c Based on 50ºF (10ºC) chilled water supply temperature and 85ºF (29ºC) tower water.
d Based on 2.4 gpm per ton (9.1 lpm per 3.517 kW).
e Based on availability of 85ºF (29ºC) tower water at 25 psi (172.4 kPa/1.7 bars) minimum.
f Multiply 460/3/60 amperage by 2.0 for 208-230/3/60 amperages; multiply by 1.2 for 380/3/60 amperages; multiply by 0.8 for
575/3/60 amperages
SCW Series Central Chilling Stations Page 13 of 77
Figure 2
Typical Two-Circuit 60-195 Ton Remote Air Cooled Chiller
SCWR-xxx Model
60 75 90 100
Cooling Capacity (tons) @ 50°F LWT 53.8 67.1 79.1 91.2
Capacity stages
EER (BTUH/W) 9.4 9.9 9.8 10
Nominal water flow (gpm) Evaporator 129 161 190 219
Evaporator manifold connection Victaulic 3 4
No. of condenser fans per condenser 3 3 4 4
Amp draw, nameplate
(460/3/60 V)
Dimensions (in.) of chiller
Dimensions (in.) of each
condenser
(lbs.)
Model
Cooling Capacity (tons) @ 50°F LWT 104.1 130.5 148.4 174.0
Capacity stages
EER (BTUH/W) 10.3 10.5 10.4 10.2
Nominal water flow (gpm) Evaporator
Evaporator manifold connection Victaulic 4 6
No. of condenser fans per condenser 4 5 6 8
Amp draw, nameplate
(460/3/60 V)
Dimensions (in.) of chiller
Dimensions (in.) of each
condenser
(lbs.)
c Based on 50ºF (10ºC) chilled water supply temperature and 95ºF (35ºC) ambient air.
d Based on 2.4 gpm per ton (9.1 lpm per 3.517 kW)
e Multiply 460/3/60 amperage by 2.0 for 208-230/3/60 amperages; multiply by 1.2 for 380/3/60 amperages; multiply by 0.8 for
575/3/60 amperages
Chiller 112 130 138 170
Condensers (per condenser) 11 11 14 14
Height 75 74
Width 100 115
Depth 45 72
Height 50
Width 45.5 45.5
Depth 180 235
Chiller 2,574 2,676 3,456 3,532 Shipping weight (lbs)
Condensers (each condenser) 1,190 1,210 1,580 1,620
Chiller 2,600 2,710 3,498 3,580 Max operating weight
Condensers 1,215 1,240 1,650 1,660
115 145 165 195
250 313 356 418
Chiller 216 250 282 316
Condensers (per condenser) 14 18 21 28
Height 77 81
Width 124 137
Depth 72 75
Height 50
Width 45.5 88
Depth 235 290 345 235
Chiller 4,156 7,528 7,554 7,698 Shipping weight (lbs)
Condensers (each condenser) 1,760 2,380 2,480 3,230
Chiller 4,212 7,788 7,814 8,016 Max operating weight
Condensers (each condenser) 1,800 2,435 2,540 3,300
Infinite Unloading
SCWR-xxx
Infinite Unloading
Page 14 of 77 SCW Series Central Chilling Stations
SCWR Series Remote Condenser Models
Fan(s) Refrigeration d
Each Connections Charge
Model Dia. Motor Amps Air flow Discharge Liquid R-134a
Number in. hp c 460V Fans cfm e ODS(in.) ODS(in.) lbs. e
SCWR60 30 1 ½ hp 3 ø 11.0 3 34,800 21/8 21/8 19
SCWR75 30 1 ½ hp 3 ø 11.0 3 32,900 21/8 21/8 19
SCWR90 30 1 ½ hp 3 ø 14.0 4 46,400 21/8 21/8 22
SCWR100 30 1 ½ hp 3 ø 14.0 4 42,400 21/8 21/8 27
SCWR115 30 1 ½ hp 3 ø 14.0 4 41,500 21/8 21/8 27
SCWR145 30 1 ½ hp 3 ø 18.0 5 51,800 25/8 25/8 43
SCWR165 30 1 ½ hp 3 ø 21.0 6 65,800 25/8 25/8 50
SCWR195 30 1 ½ hp 3 ø 21.0 8 87,800 2 @ 21/8 2 @ 21/8 44
c ø represents electrical phase; all motors are 1,140 rpm. Multiply hp by 0.746 to convert to kW.
d Refrigeration charge is for remote condenser only!
e To convert cfm to cmh, multiply by 1.699. To convert lbs. to Kg, multiply by 0.454.
SCW Series Central Chilling Stations Page 15 of 77
2 Shipping Information
2-1 Unpacking and Inspection
You should inspect your equipment for possible shipping damage.
Thoroughly check the equipment for any damage that might have
occurred in transit, such as broken or loose wiring and
components, loose hardware and mounting screws, etc.
2-2 In the Event of Shipping Damages
According to the contract terms and conditions of the Carrier, the
responsibility of the Shipper ends at the time and place of
shipment.
Notify the transportation company’s local agent if you discover
damage
Hold the damaged goods and packing material for the examining
agent’s inspection. Do not
transportation company’s inspection and authorization.
File a claim with the transportation company. Substantiate the
claim by referring to the agent’s report. A certified copy of our
invoice is available upon request. The original Bill of Lading is
attached to our original invoice. If the shipment was prepaid, write
us for a receipted transportation bill.
Advise customer service regarding your wish for assistance and to
obtain an RMA (return material authorization) number.
return any goods before the
Page 16 of 77 SCW Series Central Chilling Stations
2-3 If the Shipment is Not Complete
Check the packing list as back-ordered items are noted on the
packing list. In addition to the equipment itself, you should have:
; .................Bill of lading
; .................Packing list
; .................Operating and Installation packet
; .................Electrical schematic and panel layout drawings
; .................Component instruction manuals (if applicable)
Re-inspect the container and packing material to see if you missed
any smaller items during unpacking.
2-4 If the Shipment is Not Correct
If the shipment is not what you ordered, contact the parts and
service department immediately at (262) 641-8610. Have the
order number and item number available. Hold the items until you
receive shipping instructions.
2-5 Returns
Do not return any damaged or incorrect items until you receive
shipping instructions from the shipping department.
SCW Series Central Chilling Stations Page 17 of 77
2-6 Uncrating Your New Chiller
! WARNING !
DUE TO THE SIZE AND WEIGHT OF SCW SERIES CHILLERS,
STERLING RECOMMENDS USING BONDED PROFESSIONAL
MILLWRIGHTS TO UNLOAD AND MOVE SCW SERIES
Rig the chiller from the frame only, using spreader bars to prevent
load transfer to any chiller components. Rig the frame from at least
four points and balance the load before lifting to clear the skid. Use
a forklift of adequate size when lifting the chiller by the fork
pockets.
Insert the forks all the way into the pockets and be sure to balance
the load before lifting the chiller to clear the skid. Lift only as high
as necessary. Use a pry bar to free the skid if necessary. Lower
slowly. Retain the crating in case reshipment is necessary due to
hidden shipping damage.
Caution!
CHILLERS.
Due to the weight of these units, use extreme caution
when moving and placing SCW Series chillers.
.
Page 18 of 77 SCW Series Central Chilling Stations
- Notes -
SCW Series Central Chilling Stations Page 19 of 77
3 Installation
3-1 Installation Location Considerations
As with all equipment installations, follow all applicable codes and
regulations.
; Locate close to the process to reduce piping expense.
; Locate adjacent to drain and city water sources.
; Consult a structural engineer to assure that the floor, mounting
pad or structural steel support is of adequate strength.
; Allow for required service clearances necessary for condenser
maintenance and easy access to all components.
3-2 Making Electrical Connections
SCW Series systems are designed for three-phase voltage
operation. Refer to the unit nameplate for proper voltage and
amperage requirements.
Make sure you provide a correctly sized and protected supply of
electrical power to the unit.
Important!
Refer to National Electric Code (NEC) Article 430-24 through 430-26
for proper feeder conductor and supply disconnect sizing.
Maintain a safe ground and disconnect the power supply before
servicing the unit. A qualified electrician should make electrical
connections, and disconnect and lock out electricity using OSHA
29 CFR 1910.147 standards when you need a service call.
Check serial tag voltage and amperage requirements and make sure
your electrical service conforms before making any electrical
connections. Total running amps for the SCW Series systems are
listed on the nameplate. Customer connections can be run to the
supply terminals from either side of the unit. Make sure that all
three phases are wired correctly. If not wired properly, the unit will
run backwards. Again, check the unit nameplate for correct
voltage and amperage.
Page 20 of 77 SCW Series Central Chilling Stations
! DANGER
Improper electrical connections
will damage the unit and cause
serious operator injury or death!
Compressor damage will occur if
compressors are run backwards.
Bring properly sized power leads and ground from a fused
disconnect (installed by your electrician) to the unit. Provide
external overcurrent protection to the unit, using circuit breakers or
fuses. If you use fuses, make sure that they are dual-element timedelay fuses, sized according to your electrical code. Make sure that
all electrical connections are tight.
Important!
1. Electrical connections must comply with all applicable electrical codes.
2. The chiller must be grounded in accordance with NEC Article 250.
3. Voltage must be within plus or minus ten percent (±10%) of the nameplate
rating.
4. Make sure your installer provides external protection.
Check Compressor Rotation Before Starting Unit!
1. Connect a phase monitor and phase incoming power ABC.
2. Connect a refrigerant gauge to the suction service valve. Fully front seat
the service valve and open one full turn.
3. Bump start the compressor by switching off then on quickly 0.5 to 1
second. If the rotation is correct, the suction pressure will drop
immediately. A rise in pressure will indicate the wrong rotation. If this
occurs, change over two electrical phases of the incoming power supply
(do not change phase at the compressor starter).
Check the electrical wiring schematic
provided in your Customer Information packet
for additional information.
SCW Series Central Chilling Stations Page 21 of 77
• Never switch contactor leads or motor leads for reversing
rotation.
• Do not use contactor or motor leads for phase matching.
• Compressor damage will occur if the compressor is run in
reverse. The compressor motor protector checks for correct
phasing and will not allow it to start in reverse.
• If you discover that compressor rotation is reversed, correct it
by switching any two main power leads into the disconnect
switch or distribution block on the unit.
Note:
Check your work and proceed to the following Piping Considerations section.
3-3 Piping Considerations
Piping systems vary with process application and pump tank
configuration. Typical system configuration drawings are provided
in this manual; the details may or may not apply to your
application. Piping systems must be designed by a person
knowledgeable in piping system design and configuration.
Sterling’s Contracting Department can design and install a piping
system tailored to your process.
• All water piping returning to the pump tank must be equipped
with an inverted trap with a vacuum breaker at the high point
of the system to prevent mains from siphoning into the pump
tank.
• Run mains full size in order to reduce pressure drop in the
system and provide maximum pressures at the ends of the
mains.
3-4 Making Process Water Connections
All Models
All SCW Series chilling stations have two chilled water
connections per unit, and on water-cooled models, one more set of
water connections for condenser water:
To Process
The chilled water supply outlet leading to the process being
controlled.
Page 22 of 77 SCW Series Central Chilling Stations
From Process
The chilled water return for water returning back to the chiller
from the process to be cooled and recirculated. Adjust the
butterfly valve for the pressure drop that corresponds to the model
number of the chiller. Pressure drop is equal to supply pressure
minus return pressure
Model Water Side Pressure Drop
Condenser (each) Evaporator (each) Number
Flow (gpm) PD (psi) Flow (gpm) PD (psi)
SCWW/R60 91 4.0 72 5.3
SCWW/R75 102 4.7 90 4.5
SCWW/R90 117 4.4 107 5.6
SCWW/R100 150 5.5 123 3.9
SCWWR115 166 4.3 140 3.0
SCWW/R145 196 4.1 175 4.8
SCWW/R165 219 4.1 200 4.6
SCWW/R195 278 4.7 232 6.0
3-5 Making Tank Piping Connections
If you have purchased the SCW Series central chilling station with
the integral pump tank, please proceed with this section.
Return
Makeup
Overflow
To Drain
Bring the chilled water returning from the process to the pump
tank warm From Process side. This line is sized according to the
flow rate from the process to the pump tank. See Section 3-3 on
Page 21 for more information on piping considerations.
Important!
Do not use the SCW Series unit to support piping.
Connect a city water source to maintain water level in the pump
tank.
Connect the OVERFLOW outlet to an approved, trapped drain to
permit excess water in the pump tank to overflow to the drain. The
overflow line is sized according to the size of the pump tank.
Connect to a 1½” line (approx. 63 mm) leading to an approved,
trapped drain. You can drain the pump tank if necessary.
SCW Series Central Chilling Stations Page 23 of 77
3-6 Water Connection Sizing Considerations
Important!
• Run all external chilled water connections with adequate size to the
process.
• Provide the largest possible openings and passages for the flow of chilled
water through platens, dies, molds, or other pieces of equipment.
• Minimum external pressure drop is critical for proper operation.
3-7 Galvanic Corrosion Considerations
Water circuit piping components are primarily ferrous (iron) and
react electro-chemically with non-ferrous metallic materials such
as copper. Some water has dissolved minerals that will greatly
accelerate the reaction between dissimilar metals.
Use PVC or ferrous piping to minimize galvanic action. If piping
must be copper, use dielectric unions at the chiller.
3-8 Water Treatment Considerations
Water treatment is important in any piping system. In some
locations, raw water may be used in the system without problem;
in other locations, it will result in large deposits of scale and
corrosion.
Sterling offers a complete line of water treatment equipment.
Contact your Sterling sales representative for water testing and
treatment options.
3-9 Making Water-Cooled Condenser Connections
SCW Series water-cooled chilling stations use city or tower water
as a cooling medium. All external condenser supply and discharge
piping and connections should be of adequate size. Water
regulating valves are not required on the SCW Central Chiller if
the tower water does not fall below 65°F (18ºC). Water flow must
be adjusted based upon the pressure drop in the following table on
the next page.
Page 24 of 77 SCW Series Central Chilling Stations