Sterling SCW User Manual

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.

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

Typical Two-Circuit 60-195 Ton Water Cooled Chiller 11

Typical Two-Circuit 60-195 Ton Remote Air Cooled Chiller 13

Freezing Protection Curve 29

SCW Series Standard Control Panel 39

SCW Series Advanced Control Panel 40

SCW Series Standard Control Panel 44

SCW Series Advanced Control Panel 58

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)

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

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.

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