$30.00 Operation and Installation Manual SSC Series Central Chilling Stations Important! Read Carefully Before Attempting to Install or Operate Equipment Part No. A0551797 Bulletin No.
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. Part No. A0551797 Page 2 of 86 Effective 4/30/2008 Bulletin No.
Safety Considerations Sterling 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.
Table of Contents 1 General Information ................................................. 7 1-1 1-2 1-3 1-4 1-5 2 Shipping Information ............................................. 15 2-1 2-2 2-3 2-4 2-5 2-6 3 Unpacking and Inspection............................................................. 15 In the Event of Shipping Damages................................................ 15 If the Shipment is Not Complete.................................................... 16 If the Shipment is Not Correct ......
Table of Contents 5 Startup Checklists .................................................. 33 5-1 5-2 5-3 5-4 5-5 5-6 5-7 6 Graphic Panel Devices........................................... 41 6-1 7 Touchscreen Interface Introduction (MMI) .................................... 43 Using the SSC Series Standard Touchscreen Interface ............... 44 Getting Started on the SSC Series Standard Touchscreen Interface45 Viewing and Operating Chiller Compressors ................................
Charts and Figures 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Typical Two-Circuit 60-100 Ton Water Cooled Chiller 11 Typical Two-Circuit 60-100 Ton Remote Air Cooled Chiller 13 Freezing Protection Curve 29 SSC Series Standard Control Panel 39 SSC Series Advanced Control Panel 39 SSC Series Standard Control Panel 44 SSC Series Advanced Control Panel 58 Main Menu Screen (Advanced Control Panel) 59 Chiller Status Screen (Advanced Control Panel) 61 Chiller Configuration Screen (Advanced Contro
1 1-1 General Information Introduction Sterling SSC Series central water chilling stations are available in water-cooled and remote air-cooled designs. They differ only in the condensing media used. The SSC Series units are configured with two independent circuits using multiple compressors for each circuit. This manual lists information for these units. SSC Series chilling stations may be configured with stainless steel pump tanks for use as reservoirs for chilled water processes.
1-3 Models Covered This manual provides operation, installation, and maintenance instructions for the SSC 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.
1-5 Available Options SSC 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.
Model Number Nomeclature SSC W 060 SSC – Scroll Compressor Central Chiller Condenser Type R – Remote Air Cooled W – Water Cooled Nominal Unit Size – Tons (kW) 030 – 30 (105.4) 070 – 70 (246.0) 040 – 40 (140.6) 080 – 80 (281.2) 050 – 50 (175.7) 090 – 90 (316.3) 060 – 60 (210.9) 100 – 100 (351.
Figure 1 Typical Two-Circuit 60-100 Ton Water Cooled Chiller Model Cooling Capacity (tons) @ 50°F (10°C) LWT c Capacity stages (qty.) EER (BTUH/W) Nominal water flow (gpm) Evaporator d [lpm] Condensers e Condenser connection (no manifold) Flange Conn. (in.) Evaporator manifold connection Victaulic Amp draw, nameplate (460/3/60 V) f Height Dimensions (in.)[cm] Width Depth Shipping weight (lbs)[kg] Max operating weight (lbs.)[kg] SSC Series Central Chilling Stations SSCW-xxx 40 50 41.4 50.2 30 32.
Model Cooling Capacity (tons) @ 50°F (10 °C) LWT c Capacity stages (qty.) EER (BTUH/W) Evaporator d Nominal water flow (gpm) Condensers e [lpm] Condenser connection (no manifold) Flange Conn. (in.) Evaporator manifold connection Victaulic Amp draw, nameplate (460/3/60 V) f Height Dimensions (in.)[cm] Width Depth Shipping weight (lbs)[kg] Max operating weight (lbs.)[kg] c d e f SSCW-xxx 80 90 100 81.4 90.3 99.2 4 15.15 14.63 14.90 15.16 175 [662.4] 196 [741.9] 217 [821.4] 238 [900.9] 219 244 271 298 [829.
Figure 2 Typical Two-Circuit 60-100 Ton Remote Air Cooled Chiller Model Cooling Capacity (tons) @ 50°F LWT c Capacity stages (qty.) EER (BTUH/W) Nominal water flow (gpm) Evaporator d [lpm] Evaporator manifold connection Victaulic No. of condenser fans per condenser Chiller Amp draw, nameplate Condensers (per (460/3/60 V) e condenser) Dimensions (in.) [cm] of Height chiller Width Depth Dimensions (in.) [cm] of Height each condenser Width Depth Shipping weight (lbs) [kg] Chiller Max operating weight (lbs.
SSCR Series Remote Condenser Models Model Number SSCR30 SSCR40 SSCR50 SSCR60 SSCR70 a b SSCR80 SSCR90 a b SSCR100 Dia. in. 26 30 30 30 30 30 30 30 30 30 Motor hp c ¾ hp 3 ø 1 ½ hp 3 ø 1 ½ hp 3 ø 1 ½ hp 3 ø 1 ½ hp 3 ø 1 ½ hp 3 ø 1 ½ hp 3 ø 1 ½ hp 3 ø 1 ½ hp 3 ø 1 ½ hp 3 ø Fan(s) Refrigeration d Each Connections Charge Amps Air flow Discharge Liquid R-22 460V Fans cfm e ODS(in.) ODS(in.) lbs. e 3.9 3 20,500 15/8 11/8 7.0 2 23,200 15/8 15/8 12 7.0 2 21,900 15/8 15/8 12 10.5 3 34,800 21/8 21/8 19 10.
2 2-1 Shipping Information Unpacking and Inspection You should inspect your central chilling station for possible shipping damage. If the container and packing materials are in reusable condition, save them for reshipment if necessary. 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. In case of breakage, damage, shortage, or incorrect shipment, refer to the following sections.
2-3 If the Shipment is Not Complete Check the packing list. The apparent shortage may be intentional. Back-ordered items are noted on the packing list. You should have: ; ; ; ; ; ; ; Sterling SSC Series central chilling station Bill of lading Packing list Operating and Installation packet Electrical schematic and panel layout drawings Component instruction manuals Parts list Re-inspect the container and packing material to see if you missed any smaller items during unpacking.
2-6 Uncrating Your New Chiller ! WARNING ! DUE TO THE SIZE AND WEIGHT OF SSC SERIES CHILLERS, STERLING RECOMMENDS USING BONDED PROFESSIONAL MILLWRIGHTS TO UNLOAD AND MOVE SSC SERIES CHILLERS. 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.
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3 3-1 Installation 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.
! DANGER Improper electrical connections can damage the unit and cause serious operator injury or death! 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.
Note: • Never switch contactor leads or motor leads for reversing rotation. • Do not use contactor or motor leads for phase matching. • Compressor noise from reverse rotation is noticeable. Do not run in this mode for more than ten (10) seconds. The compressor shuts off if it is run longer in this mode. • Reverse rotation can cause suction and discharge pressures to be approximately equal; amp draws will be lower than normal.
To Process The chilled water supply outlet leading to the process being controlled. From Process The chilled water return for water returning back to the chiller from the process to be cooled and recirculated. 3-5 Making Tank Piping Connections If you have purchased the SSC Series central chilling station with the integral pump tank, please proceed with this section. Return Bring the chilled water returning from the process to the pump tank warm From Process side.
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.
Two connections are made to each SSC Series unit: Condenser Water In The city or tower water supply inlet is located at the side or rear of the chiller. • Water pressure ≥25 psi (≥172.4 kPa/≥1.72 bars) • Water temperature ≤85°F (≤29ºC) Condenser Water Out The return outlet, located at the chiller side or rear is connected to a cooling tower inlet, a sewer or other approved discharge receiver. • A water regulating valve is a standard feature in the condenser water out line.
SSC Series condensing pressure with 95ºF (35ºC) condenser air R-22 = 260 psi (1,793 kPa/17.93 bars) Note: Due to the variables involved in remote air-cooled condenser installations, no set or standard piping procedure exists. Each installation must be designed and installed by qualified persons. Follow the instructions supplied with the condenser. 3-11 Checking Motor Direction Compressor Note: • Never switch contactor leads or motor leads for reversing rotation.
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4 4-1 Sequence Of Operation Staging 1. The system uses a PID control algorithm to regulate the chilled water temperature. As the required control effort increases or decreases, the system compressors are turned on or off to keep the temperature at the specified set-point 2. Compressor anti-recycle time is three (3) minutes. 4-2 Alarms If a fault occurs, that compressor or circuit is deactivated. The load will automatically shift to any other compressors that are currently ON-LINE, but not running.
4-5 Chilled Water Circuit If your central chilling station is equipped with the optional integral pump tank, make the process cooling water supply connection at the P1 manifold at the left side of the pump tank at the exposed connection. Bring the process cooling water return connection to the Hot well of the tank on the right side at the flanged connection. Warm coolant (water and ethylene glycol mixture) returns from the process to the tank, then gets pumped through the evaporator where it is cooled.
If you want lower chilled water temperatures, you’ll need to mix process water with industrial- (not automotive) grade ethylene or propylene glycol with rust inhibitor to provide protection down to 20°F (12ºC) below the operating temperature you want. Figure 3 below shows the proper mixtures needed to provide protection to 20°F (12ºC) below the operating temperature you want. You can then reset the freezestat cutout temperature to a temperature 10°F (6ºC) below the operating temperature you selected.
4-8 High Pressure Cutout This electro-mechanical safety feature opens the control circuit if the system condensing pressure exceeds a safe level. High pressure cutout setting Model psi SSC Series water-cooled chilling stations 290 psi SSC Series remote air-cooled chilling stations 375 psi kPa 2,000 kPa 2,586 kPa bars 20 bars 26 bars Important! The high pressure cutout is a manual reset control, so you should reset it once.
4-11 Control Nipple All SSC Series chilling station evaporators have two control nipples. The flow switch, freezestat, and flush port are located in the control nipple. Optional pressure gages can be mounted in the control nipples to aid in achieving proper flow through the evaporator and balancing flows. Coupling mounts for customer-installed pressure gauges are included on both control nipples.
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5 5-1 Startup Checklists Introduction Important! These lists assume the installation information in this manual has been read and followed. Have new chillers started up and checked by a qualified refrigeration service technician. Sterling offers factory startup for SSC Series Series chilling stations. Call the Sterling Service Department at 1 (800) 233-4819 for more details.
; Complete all piping leading to and from the pump tank. Observe all applicable codes. ; Complete all electrical wiring. Observe all applicable codes. ; Prepare all related equipment in the system for operation. Note: • Never switch contactor leads or motor leads for reversing rotation. • Do not use contactor or motor leads for phase matching. • Compressor noise from reverse rotation is noticeable. Do not run in this mode for more than ten (10) seconds.
; Check the water level in the pump tank to be sure the pump does not run dry while the system piping is being filled. ; Check your work and proceed to the Startup procedure. 5-3 Water-Cooled SSC Series Startup 1. Start the chiller by pushing the Start button on the control panel of the unit. 2. The touchscreen will display the Main Menu screen. 3. If your chiller has been setup to control the pump tank, the recirculation pump will turn on first, then after 5 seconds the process pump will turn on.
; Electrical connections must conform to all applicable codes. ; Complete the chilled water TO and FROM PROCESS connections. ; The optional or field installed chilled water supply and return valves must be open. ; Be sure the tank and chilled water circuit piping are filled with a water/glycol mixture. The water/glycol mix should provide freeze protection to 20°F below the leaving water temperature you’ve selected. ; The air cooled condenser should have an adequate supply of air for proper operation.
; Check for proper pump rotation direction. To confirm proper rotation: 1. Observe a pump pressure gauge connected to the suction and discharge sides of the pump casing through two ¼” (approx. 6.4 mm) gauge cocks. 2. Close the gauge cock leading to the pump suction and open the gauge cock leading to the pump discharge. 3. Close the discharge butterfly valve, crack it open, then start the pump and observe the gauge. • If the gauge indicates within 15 psi (103.4 kPa/1.
Note: If the recirculation pump does not turn on (or that the flow switch is not satisfied) the compressors will not be allowed to turn on. 6. Check the pump(s) amp draws and pressures. The amp draws must be within the pump(s) running load and service factor amps. 7. Operate the chiller, looking for leaks and listening for unusual noises or vibrations that could indicate improper operation. 8.
Figure 4 SSC Series Standard Control Panel Figure 5 SSC Series Advanced Control Panel SSC Series Central Chilling Stations Page 39 of 86
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6 6-1 Graphic Panel Devices Indicator Lights and Control Switches (MMI) System On The green System On indicator lights when the main power switch is on and the control circuit is energized. Start The Start push-button lets you energize the unit. Stop The Stop push-button lets you de-energize the unit. Touchscreen Interface The color touchscreen interface gives you control over the chilling station.
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Using the Standard Touchscreen Interface 7 7-1 Touchscreen Interface Introduction (MMI) The Standard touchscreen interfaces let you control your SSC Series central chilling station. You can do such things as: • Control compressors and optional pumps • View current statuses of operation, such as pressures, temperatures, and capacities • Handle alarm conditions The sections in this chapter list special instructions for operating either touchscreen interfaces.
Figure 6 SSC Series Standard Control Panel 7-2 Using the SSC Series Standard Touchscreen Interface The SSC Series Standard touchscreen interface is the “manager” of your SSC Series central chilling station. The screen contains screen buttons you can press to control system operation. For example, if you need to resolve an alarm condition, press the or buttons on the right side of the screen to highlight “ACTIVE ALARM LIST”.
7-3 Getting Started on the SSC Series Standard Touchscreen Interface To start the SSC Series Standard touchscreen interface: Push the ON/OFF button on the cabinet. The SSC Series control panel energizes and the System On indicator turns on.
• “CONFIGURATION MENU” contains the chiller setup parameters (i.e. chiller setpoint, and high and low temperature alarm setpoints) The following sections in this chapter list the information you need to navigate through these screens for operating and monitoring your SSC Series central chilling station with the Standard Control Package.
2. READY – Indicates that the compressor is enabled and ready to run. However, the current loading does not require the compressor to be running. This compressor will be automatically started when needed. 3. RUNNING – Compressor is currently running. 4. FAULT – A safety on the compressor indicates a fault condition and the compressor has been deactivated. Once the problem is remedied, the compressor will return to a READY state unless it is put in the OFFLINE state.
The compressor enable screen displays: Compressor Enable Screen These screens allow the customer to toggle the compressors between ON-LINE and OFF-LINE. As the operator presses the F1 or F2 button, the corresponding compressor state changes between ON-LINE and OFF-LINE. Setting Compressor Lead/Lag Times and Activating Compressor Lead/Lag Operation While in the Configuration Menu, the compressor lead/lag screen allows the customer to enable or disable the Lead/Lag rotation of compressors.
Viewing Compressor Run Times From the Main Menu, use the or buttons to highlight the “HOURMETERS” menu. Scroll to select the compressors. Then press ↵ to display the hourmeter. Note: this is a complete list of all components that may be included in the system. Any component that is not included in the system will not accumulate time. The Compressor Run Time screen displays: Compressor Run Time Display Screen Two hourmeters are kept for each compressor in the system. The first is a lifetime meter.
7-5 Viewing and Operating Chiller Pumps If your chiller system was configured to operate the pump(s) of the chilled water pump tank the user may view the status of the process and recirculation pumps. Viewing Chiller Pump Status To view the status of the pumps, start from the Main Menu, then: Press the or buttons to highlight either “PROC PUMP STATUS”or “RECIRC PUMP STATUS”.
Operating Chiller Pumps To turn on and off the pumps, start from the Main Menu, then: Press the or buttons to highlight either “CONFIGURATION MENU”. Press ↵ Highlight “PUMP ENABLES” Press ↵ Highlight the pump you want to operate. The Pump Enables Screen appears Pump Enables Screen Any pump that is disabled to the OFF-LINE position will not be called to operate. Simply toggle the F1 key on the enable/disable screen to toggle the state of the pump from the ON-LINE to OFFLINE state.
The compressor lead/lag screen displays: Pump Lead/Lag Screen Viewing Pump Run Times From the Main Menu, use the or buttons to highlight the “HOURMETERS” menu. Scroll to select the pump. Then press ↵ to display the hourmeter. Note: this is a complete list of all pumps that may be included in the system. Any pump that is not included in the system will not accumulate time.
Two hourmeters are kept for each compressor in the system. The first is a lifetime meter. This measures the total time that the pump has been operational in the lifetime of the chiller. The second is a resettable hourmeter. This hourmeter can be cleared to monitor run time on specific intervals.
To acknowledge the alarm, press F1 to clear the alarm. It will then appear in the alarm history screen. Except for High and Low Water Temperature, and Low Refrigerant Pressure, these alarms are considered fatal and maintenance must be preformed in order to allow the chiller to fully run. Should a compressor or pump turn off from an alarm condition, the remaining will shut down and display FAULT in the status screen for the device.
7-7 Viewing and Setting System Temperatures To view the actual process temperature select any of the status screens from the main menu. The process temperature is located on the bottom of the screen. For example, the compressor status displays: Compressor Status Screen Note: If you have a metric version of the SSC Series controller, the screens display in converted metric values. Setting System Temperatures The chiller setpoints are set through the configuration menu.
↵ Once the value is correct, press the button to make the change. In the event that the value is outside the range specified by MAX or MIN, the value entered will be the corresponding MAX or MIN.
Using the Advanced Touchscreen Interface 8 8-1 Touchscreen Interface Introduction (MMI) The Advanced touchscreen interfaces let you control your SSC Series central chilling station. You can do such things as: • Control compressors and optional pumps • View current statuses of operation, such as pressures, temperatures, and capacities • Handle alarm conditions The sections in this chapter list special instructions for operating either touchscreen interfaces.
Figure 7 SSC Series Advanced Control Panel 8-2 Using the SSC Series Advanced Touchscreen Interface The SSC Series Advanced touchscreen interface is the “manager” of your SSC Series central chilling station. This screen contains screen buttons you can press to control system operation. For example, if you need to resolve an alarm condition, press the Up or Down arrow buttons on the right side of the screen to highlight “ACTIVE ALARMS”.
8-3 Getting Started on the SSC Series Advanced Touchscreen Interface To start the SSC Series Standard touchscreen interface: Push the ON/OFF button on the cabinet. The SSC Series control panel energizes and the System On indicator turns on. The Main Menu screen displays: Figure 8 Main Menu Screen The Main Menu screen lets you gain access to: • “Active Alarms” contains the current alarm(s) of the system • “Al;arm History” contains the last thirty (30) alarms that were activated.
• “Compressor Hourmeters” contains the lifetime and resettable hour meters to show the number of hours that the compressors have been running • If the chiller was configured to operate the chilled water pump tank, there are three screens to configure and view the pump tank setup.
Figure 9 Chiller Status Screen The Chiller Status screen shows the status for compressors within the system. Only compressors that are included in the system will be shown on this screen. Compressors will display one of the following states: 1. OFFLINE – This indicates that the compressor has been turned off in the compressor enable/disable screen. The compressor will not be called to operate until it has been re-enabled. The color code for this indication is black. 2.
problem is remedied, the compressor will return to a READY state unless it is put in the OFFLINE state. The color code for this indication is red.
Setting Compressor Lead/Lag Times and Activating Compressor Lead/Lag Operation While in the Configuration Menu, the compressors can be setup in a lead/lag configuration using interval hours. By pressing the “Compressor Rotation Interval” button, a numeric keypad will be displayed and allow the user to change the timeframe of the interval. To activate the Lead/Lag operation touch the “Compressor Rotation” button.
Compressor Run Time Display Screen Two hourmeters are kept for each compressor in the system. The first is a lifetime meter. This measures the total time that the compressor has been operational in the lifetime of the chiller. The second is a resettable hourmeter. This hourmeter can be cleared to monitor run time on specific intervals.
Viewing Chiller Pump Status To view the status of the pumps, start from the Main Menu, then: Press the Up or Down buttons to highlight either “System Information”. Press ↵ The Pump Status Screen appears Figure 12 Pump Status Screen Only pumps that are included in the system will be shown on this screen. Pumps will display one of the following states: 1. OFFLINE – This indicates that the pump has been turned off in the pump enable/disable screen.
2. READY – Indicates that the pump is enabled and ready to run. However, the current number of pumps specified to run does not require this pump to operate. The color code for this indication is yellow. 3. RUNNING – Pump is currently running. The color code for this indication is green. 4. FAULT – A safety on the pump indicates a fault condition and the pump has been deactivated. Once the problem is remedied, the pump will return to a READY state unless it is put in the OFFLINE state.
Any pump that is disabled to the OFF-LINE position will not be called to operate. Simply press the button of the desired pump to toggle the state of the pump from the ON-LINE to OFF-LINE state. Setting Pump Lead/Lag Times and Activating Pump Lead/Lag Operation While in the Configuration Menu, the pump lead/lag (rotation) can be enabled or disabled. Simply press the Process or Recirculation Pump Interval button on the screen to toggle between Enabled and Disabled.
Figure 14 Pump Run Time Display Screen Two hourmeters are kept for each compressor in the system. The first is a lifetime meter. This measures the total time that the pump has been operational in the lifetime of the chiller. The second is a resettable hourmeter. This hourmeter can be cleared to monitor run time on specific intervals.
Compressor Motor Protector Fault (One for each compressor) Chilled Water Circuit Low Flow (One per chilled water circuit) Chilled Water Circuit Freezestat (One per chilled water circuit) Chilled Water Circuit High Pressure (One per chilled water circuit) Chilled Water Circuit Low Pressure (One per chilled water circuit) Pump motor overload (One per system pump) If an alarm condition occurs the follow screen is displayed: Figure 15 Alarm Condition Screen To acknowledge the alarm, press the alarm
pump turn off from an alarm condition the remaining will shut down and display FAULT in the status screen for the device. Once a device has gone offline you will need to contact a licensed professional (electrician or refrigeration sevice company) to bring the device back online. ! CAUTION Never attempt to service a unit until a qualified electrician has opened and locked out the main disconnect using OSHA 1910.147 standards. All electrical connections must be done by a qualified electrician.
8-7 Viewing and Setting System Temperatures To view the actual process temperature start at the Main Menu and Use the Up or Down arrows to highlight “System Information” Press ↵ The system status displays: Figure 16 System Status Screen Note: If you have a metric version of the SSC Series controller, the screens display in converted metric values.
Setting System Temperatures The chiller setpoints are set through the compressor configuration menu.
9 9-1 Routine Maintenance Lubrication Grease all fan bearings, fan motors, and pump motors that do not have permanently sealed bearings. Remove the grease relief plug (motors only) before adding grease. Failure to do so may dislodge the bearing grease retainer which will eventually cause bearing failure. Lubricate components regularly, based only on the component manufacturer’s specifications for frequency and lubricant.
9-3 Evaporator Maintenance The evaporator(s) may be accessed for back-flushing by removal of the 2” plug (approx. 51 mm) in the return control nipple and the flow switch in the supply control nipple. If the suggested piping recommendations have been followed, one circuit of a multiple circuit chiller may be back-flushed without shutting down the entire system. Check Y-strainer for any clogging. 9-4 Pump Motor Seal Pump seals require water for lubrication, so the pump(s) must never be run dry.
9-7 Preventive Maintenance Service A systematic preventive maintenance program helps avoid costly down time. Call the Service Department at Sterling to arrange a schedule of inspections. This service, described in Sterling Bulletin No. 10-106.3, is tailored to fit your maintenance requirements. Inspections include: ; Check refrigerant suction and discharge pressures. ; Check safety and operating controls. ; Check voltage and amperage of all motors. ; Check all electrical connections.
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10 Troubleshooting Problem Possible Cause No power. Wrong voltage supplied to unit. Defective On/Off switch. Control circuit fuse blown. Unit does not run. Defective control transformer. Flow switch circuit is open. Pump motor off on overload. Unit is off on flow switch or pressure switch. Freeze control set higher than temperature of liquid in system. Pump runs, compressor does not. High pressure refrigerant cutout switch contacts open.
Problem Possible Cause Compressor internal overload open. Pump runs, compressor does not (cont’d). Compressor contactor holding coil open. Defective fan motor. Fan motor out on overload. Defective freezestat. Refrigerant low. Defective fan cycling control. Low refrigerant pressure switch contact open. Defective pump motor interlock to compressor control circuit. Broken wire in the compressor control circuit. Freezestat control setting is too high. Pump runs, compressor cycles at short intervals.
Problem Possible Cause Pump is running in reverse. Pump pressure is too low. Check for foreign matter. Process water pressure low, pressure at pump high. Evaporator frozen. Restricted condenser air flow. Refrigerant not feeding. Unit runs continuously, but not enough cooling power. Improper water/glycol solution. Poor heat transfer in evaporator. Unit low on refrigerant. Low water flow through evaporator. Inefficient compressor. Unit under-sized for application.
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I Alarms Advanced Controls, 68 Standard Controls, 53 Available options, 9 Checking Motor Direction, 25 Chiller Pumps Advanced Controls, 64 Chiller Shutdown, 38 Circuit Alarm Sequence, 27 Compressor Lead-Lag, 27 Compressor Staging Sequence, 27, 31 Condenser Maintenance, 73 Copyright information, 2 Determining Flow Rate, 38 Disclaimer information, 2 Electrical connections, 19 Electrical wiring schematics, 20 Evaporator Maintenance, 74 Freezestat Control, 28 Galvanic Corrosion Considerations, 23 General inform
Water Cooled Startup Checklist, 33 Page 82 of 86 Water Treatment Considerations, 23 Water-Cooled Condenser Connections, 23 SSC Series Central Chilling Stations
Service Notes SSC Series Central Chilling Stations Page 83 of 86
Service Notes Page 84 of 86 SSC Series Central Chilling Stations
Service Notes SSC Series Central Chilling Stations Page 85 of 86
Technical Assistance Parts Department Call toll-free 7am–6pm CST [262]-641-8610 or fax [262] 641-8653 The ACS Customer Service Group will provide your company with genuine OEM quality parts manufactured to engineering design specifications, which will maximize your equipment’s performance and efficiency. To assist in expediting your phone or fax order, please have the model and serial number of you unit when you contact us. A customer replacement parts list is included in this manual for your convenience.
