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Black Box CRCW-12 User Manual Download Page 15

724-746-5500   |   blackbox.com 

724-746-5500   |   blackbox.com 

Page 15

Chapter 1: Introduction

1.5 General Design

The Cold Row CW unit is housed in a steel frame cabinet rated for indoor use. The exterior of the cabinet is coated with a pow-
der coat finish to protect against corrosion. Removable access panels are located on the front and rear of the cabinet for easy 
access to all components. Operator controls are conveniently located on the front of the cabinet.

NOTE:  Customer-specified non-standard features or design variations may not be described in this manual. Refer to the installation 

and/or electrical drawings supplied with your unit for details of additional feature(s). In some cases, an addendum to this 
manual may also be included to further describe the feature(s).

Figure 1-2 depicts a typical internal layout and identifies the major components of a typical Cold Row CW (CRCW-12) unit. The 
location of some components may vary.

CW valve

Electric box

Air filters

T/H sensor

Supply/return pipe 

transition plate

Temperature  

sensor

Temperature  

sensor

Temperature  

sensor

Disconnect 

switch

Swing-out 

hinge

Float switch

Drain pans

EC fan (3)

Coil

Caster  

housing

Level adjustment 

screw (4)

Figure 1-2. Typical internal layout: Cold Row CW (CRCW-12).

NOTE: In Figure 1-2, cabinet access panels are removed to show internal parts.

Summary of Contents for CRCW-12

Page 1: ...r Manual CRCW 12 CRCW 24 Order toll free in the U S Call 877 877 BBOX outside U S call 724 746 5500 FREE technical support 24 hours a day 7 days a week Call 724 746 5500 or fax 724 746 0746 Mailing ad...

Page 2: ...be live with one of our technical experts in less than 30 seconds Trademarks Used in this Manual Black Box and the Double Diamond logo are registered trademarks and Cold Row is a trademark of BB Techn...

Page 3: ...en the equipment is operated in a commercial environment Operation of this equipment in a residential area is likely to cause interference in which case the user at his own expense will be required to...

Page 4: ...n el flujo de aire por los orificios de ventilaci n 10 El equipo el ctrico deber ser situado fuera del alcance de fuentes de calor como radiadores registros de calor estufas u otros aparatos incluyend...

Page 5: ...ment 19 2 2 Moving the Equipment 19 2 3 Site Preparation 19 2 4 Mounting Placement 20 2 5 Air Distribution 21 2 6 Optional Equipment Field Installed 23 2 6 1 Remote Water Detectors 23 2 6 2 Remote Tem...

Page 6: ...8 4 2 3 Display Variables 39 4 2 4 Cursor Position in Screens 39 4 2 5 Modifiable Variables 40 4 2 6 Password Authorization Levels 40 4 2 6 1 Password Protected Screen 40 4 2 6 2 Wrong Password 41 4 2...

Page 7: ...4 5 2 13 Dual Power 55 4 5 2 14 Software Version Date 55 4 5 3 Alarm Log 55 4 5 3 1 Alarms 55 4 5 3 2 Non Critical Alarms 56 4 5 3 3 Critical Alarms 57 4 5 3 4 Alarm Screen Messages 57 4 5 4 Control M...

Page 8: ...3 Lead Controller Group Sensors 95 4 6 2 8 4 Group Sensor Status 95 4 7 BMS Communications 96 4 7 1 Direct BMS Control 97 4 7 2 BMS Communication 97 4 8 Troubleshooting the Control I O Module 98 4 9...

Page 9: ...ment 114 5 3 2 2 Fan Replacement 116 5 3 2 3 Condensate Pump Replacement 117 6 Troubleshooting 119 6 1 Contacting Technical Support 119 6 2 Obtaining Warranty Parts 119 6 3 Obtaining Spare Replacement...

Page 10: ...uration is used with your system NOTE Cold Row systems capture and neutralize heat within close coupled rack based environments Any use beyond what is described in this manual is deemed to be not inte...

Page 11: ...724 746 5500 blackbox com Page 11 Chapter 1 Introduction Figure 1 1 User interface display Refer to Chapter 4 for detailed instructions on operating the system controller...

Page 12: ...ment within 90 days from the date of shipment the warranty will commence on the 91st day from equipment shipment This limited warranty does not include labor freon or any other expense required to rep...

Page 13: ...rigeration mechanic or air conditioning technician CAUTION When moving the unit it should be kept in its normal installed position If the unit is not kept level and vertical damage to the compressors...

Page 14: ...prolonged exposure of skin to cleaning solvents Wash exposed skin thoroughly after contact with solvents CAUTION The air intake and discharge areas must be free of obstructions Make sure access panels...

Page 15: ...e installation and or electrical drawings supplied with your unit for details of additional feature s In some cases an addendum to this manual may also be included to further describe the feature s Fi...

Page 16: ...d Off to gain access to the electrical compartment The service disconnect switch may be used to turn the unit off for emergency shutdown or when routine maintenance is performed The handle of the swit...

Page 17: ...ensor The NTC sensors are factory installed in predetermined supply air fan zones inside the cabinet Each NTC sensor is used by the system controller to manage the speed of the fan for that zone to me...

Page 18: ...ervice disconnect switches are provided on the electric box to connect two independent power sources If the primary power source Power Supply A is interrupted or if an under voltage phase loss or imba...

Page 19: ...stems are designed to be kept in a vertical position The cabinet is equipped with shipping support brackets that are bolted to the skid to facilitate moving the unit before installation Move the unit...

Page 20: ...t adds to the cooling load while maintaining the requirement of the Indoor Air Quality IAQ standard Lack of these steps can cause erratic operation unstable room control and excessive maintenance cost...

Page 21: ...cks are installed on each side of the Cold Row cabinet The cabinet is equipped with an adjustable foot at each corner to raise the cabinet off the casters after the unit is positioned in its operating...

Page 22: ...e supply air out of the Cold Row unit where it will be drawn into the front of the server racks An optional front diverted air discharge panel is also available This directs the supply air sideways ou...

Page 23: ...The base has a mounting hole in the center that you can use to secure the water detector in place Figure 2 4 Spot type water detector NOTE Do not place the spot type water detector on an electrically...

Page 24: ...rom the base of the sensor by squeezing it at the top and bottom CAUTION Be careful not to damage the exposed temperature humidity sensors on the PC board when removing the cover The sensors can be da...

Page 25: ...supply and return connections are made outside the cabinet On units that are piped from the bottom the chilled water supply and return connections are made inside the cabinet Pipe connections are thre...

Page 26: ...d the entrance holes so air won t leak around the pipes NOTE Chilled water lines should be insulated to prevent condensation from forming on the pipes if ambient dew point temperatures are higher than...

Page 27: ...pply and Return Piping Connections 24 Cabinets Female pipe threads Condensate drain 1 2 FPT Schrader valve Top access piping Pump Male pipe threads Schrader valves Bottom access piping Pump Condensate...

Page 28: ...ute a 3 8 ID flexible drain tubing through the bottom of the cabinet and connect it to the barbed drain stub located on top of the humidifier drain pump NOTE The humidifier drains hot water into the d...

Page 29: ...the unit must be within 10 of the voltage specified on the system nameplate except for 208 230 V single phase units that have a different tolerance listed below A main distribution panel must be prov...

Page 30: ...ay route the wires through the top or bottom of the cabinet as preferred using the available knock outs Refer to the electrical drawing supplied with your unit to determine the total number of interco...

Page 31: ...rawing supplied with your unit to determine which type valve is provided Location and size of chilled water valve differs with the size of the A C unit The chilled water valves are factory set for the...

Page 32: ...n The Black Box logo in the display is replaced with a blower symbol 5 A 45 second time delay is allowed after the first fan turns on before the controller polls the air proving switch If adequate air...

Page 33: ...g Management System BMS may be used to directly interface to the E2 controller The operator may view all the available menu screens through a BMS however changes may be made only to basic parameters s...

Page 34: ...ifications to the control setpoints require the use of a password 4 1 1 2 Password Protection You can access the Info menu and Alarms log without a password The controller recognizes predetermined sec...

Page 35: ...fferent interface menu levels to the operator Information Control Service and Factory These menus permit the user to easily view control and configure operating parameters for the A C unit See Menu Se...

Page 36: ...red by pressing the alarm key 4 1 3 Controller I O Module The controller is a microprocessor based I O module mounted inside the A C system electric box see Figure 4 2 The controller I O module contai...

Page 37: ...re 4 3 This can be field connected through a serial interface to a Building Management System via Modbus BACnet SNMP or HTTP protocol as configured by the factory A controller interfaced to a network...

Page 38: ...the Main Menu by using the up and down arrow keys When the desired menu is centered in the screen with bold capital letters and an arrow symbol is pointing towards the Enter key you may press the Ente...

Page 39: ...d you may use the Enter key to insert a flashing cursor in the modifiable fields within that screen Flashing cursor Figure 4 8 Flashing cursor If the flashing cursor is located in a modifiable field t...

Page 40: ...t to select a secure menu in a given session the Enter Password screen will be displayed This screen displays the current security level authorized Current security level Access ID code Figure 4 10 En...

Page 41: ...01 for the Control menu Level 1 and to 0002 for the Service menu Level 2 Upon entering the Service Save Cfg menu the operator can change the passwords for the menus If changed from that point on only...

Page 42: ...n stages with five second time delays The middle fan starts first then the upper fan then the lower fan 6 Following a 45 second time delay after the first fan turns on the controller polls the air pro...

Page 43: ...enu select Setpoints by scrolling through the menu selections with the Up and Down arrow keys and pressing the Enter key when SET appears in bold capital letters in the center of the screen Figure 4 1...

Page 44: ...e restored from the Service menu Whichever setpoints are restored Factory or Customer become the current operating setpoints 4 3 2 Alarms As programmed into the system controller an alarm condition ac...

Page 45: ...gured to activate up to three custom alarms One custom alarm with relay contacts is provided as a standard and up to two additional custom alarms may be provided as an option 4 4 Controller Operation...

Page 46: ...middle and lower as measured by temperature sensors mounted locally to each zone inside the Cold Row cabinet The controller also monitors a temperature humidity T H sensor that is mounted in the retur...

Page 47: ...ntrol standard or dewpoint control optional for cooling dehumidification and humidification functions The control method selected in the Factory menu determines which sensors the controller uses to ma...

Page 48: ...aintain the temperature setpoint The control output is matched to the valve If the valve typically opens at 2 5 VDC the control I O module will generate the appropriate voltage for opening the valve s...

Page 49: ...ler a Locked rotor b Loss of a phase c Low main supply voltage d Overheating of electronics e Overheating of monitor If one of the fans fails to operate the controller alerts the operator with an alar...

Page 50: ...disables all control outputs and a message Off by Remote Shutdown appears in the main display screen The A C system will automatically be reenabled when the remote On Off signal calls for the A C uni...

Page 51: ...oller to the customer or factory default values Level 2 password is needed to enter this menu Factory allows modification of more advanced control parameters such as sensor scaling startup delays and...

Page 52: ...lop control output signals for managing system operations 4 5 2 2 Return Temperature Sensor Displays relative humidity as measured by the return temperature humidity T H sensor inputs The return T H s...

Page 53: ...ure Sensor screen shown in 4 5 2 6 if your unit is configured for static pressure control instead of zone temperature control This screen displays the current operating static pressure The static pres...

Page 54: ...0 that controls each fan appears in the field to the right of each symbol The message Var from Avg or Temp Prop appears indicating the system is in a zone cooling control configuration see Section 4 4...

Page 55: ...om the main menu any other active alarm message s may be viewed by using the Up and Down arrow keys to scroll through alarm messages 4 5 3 1 Alarms The red LED backlight within the alarm key will illu...

Page 56: ...ed with These alarms are programmed to activate the Summary Fault alarm and close the Summary Fault relay contacts without stopping unit operation Some examples of the factory programmed non critical...

Page 57: ...e External and or internal communication lost BMS or pLAN Condensate Pan Full Full Water level in condensate pan is reaching an unsafe level Moisture Water sensed by any combination of a leak detector...

Page 58: ...control parameters and compare them to system level operating data derived from the various sensor transmitter inputs See Section 4 5 4 1 The Alarm Setpoints ALARM SET screens allow you to enable and...

Page 59: ...transmitter inputs Figure 4 26 Static Pressure screen The Static Pressure screen only appears if your unit is configured for static pressure control at the factory It allows you to adjust the static p...

Page 60: ...n icons indicating which fan zones have been linked The lower two fields disappear from the Fan Control screen when the system is in the humidification or dehumidification modes In these modes individ...

Page 61: ...Water Temperature Alarm Figure 4 34 Low Entering Water Temperature Alarm Following the alarm enable screens are the alarm offset screens From these screens you may adjust offsets for the high and low...

Page 62: ...cancel at 75 F Conversely the low temperature alarm will cancel when the actual temperature rises to the Low Temperature Alarm setpoint 60 0 F the Offset 5 0 F or 60 0 F 5 0 F 65 0 F The Low Temperatu...

Page 63: ...en The Clock screens may be accessed from the Control menu From this screen you may set the time date and day Figure 4 39 Set Clock screen The Set Clock screen allows you to set and or adjust the curr...

Page 64: ...Chapter 4 E2 Controller Figure 4 41 Service menu loop selections 4 5 5 1 Cool The Service Cool menu screens below apply to your unit that s configured for CW operation Figure 4 42 Cool menu CW Cooling...

Page 65: ...ng This screen also displays the current air temperature and setpoint temperature The current proportional control output signal to the CW control valve is shown at the bottom of the screen 4 5 5 2 Hu...

Page 66: ...ce The alarm log is cleared by pressing the Alarm key while in this menu NOTE If the Alarm key is pressed when in any of the Service Alarms screens all stored alarm messages will be permanently erased...

Page 67: ...re available for optional sensors if enabled at the factory such as Remote Supply Air Temp and Remote Supply Air Humidity NOTE When calibrating sensors an offset at one extreme may produce an error at...

Page 68: ...you must access the Factory level menu Contact Tech Support See Section 6 0 for the password that allows access to the Factory menu and for guidance on setting the PI control values 4 5 5 5 2 Tempera...

Page 69: ...during humidification Figure 4 53 If the Hum Speed is set to 80 the lower fan will run at 75 during humidification as it is limited by the maximum speed setting for the lower temperature zone Figure...

Page 70: ...nal or a critical alarm Suppress Buzzer allows you to enable or disable the alarm signal buzzer 4 5 5 6 2 Unit Timers Figure 4 57 Unit Timers screen The Service Options Unit Timers screen allows you t...

Page 71: ...6 F Setpoint 72 0 F 2 0 x Cut out Offset 0 3 F 72 0 F 0 6 F 72 6 F EXAMPLE 3 Humidity Offset Multiplier With the default cut in offset for humidity at 5 if a multiplier of 0 7 is entered M 0 7 x 5 3...

Page 72: ...bled a customer provided alarm input may be used to activate the Summary Alarm relay and show a specific Customer Alarm message in the alarm display screen A Customer Alarm message may simply be displ...

Page 73: ...the occurrence of moisture alarm condensate pan pump or failure of the return humidity sensor you would enter the following bitmask values for the applicable alarm numbers and enter 0 for the rest Cus...

Page 74: ...nd any sensor failure Only the enabled sensors can generate an alarm To enable an additional custom alarm add the alarm bitmask number to the factory default total and enter the new total for the appl...

Page 75: ...or fail 8 8 29 Return humidity sensor fail 16 16 30 DX1 discharge pressure fail 32 32 31 Static air pressure sensor fail 64 64 32 DX1 suction press sensor fail 128 128 Factory Default Bitmask Total 25...

Page 76: ...48 Reserved 128 0 Factory Default Bitmask Total 0 4 5 5 6 8 Workgroup Screens The Service Group display screens shown below only appear if two or more units are wired together as a group They allow y...

Page 77: ...creens From the Service Run Hours menu you may access a loop consisting of the component run hours display screens applicable to your unit using the Up and Down arrow keys Each screen displays the num...

Page 78: ...ice Save Cfg menu Figure 4 68 Customer Save screen The first Service Save Cfg menu screen allows you to save any adjustments made in service level menu screens as the new Customer parameters or restor...

Page 79: ...out 43 RH Dehumidify Cut in 50 RH Dehumidify Cut out 47 RH Figure 4 69 Set Passwords screen The second Service Save Cfg menu screen allows you to set new passwords for entering the Control and Service...

Page 80: ...iple A C units 4 6 1 Workgroup Setup The controller may be networked with a group of A C unit controllers to manage their outputs as a system in an N M M number of standby units group The controllers...

Page 81: ...the grouped A C units to promote equal run time and will rotate the role of group lead When set up for unit rotation the A C units will rotate duty in order of their group addresses Active Capacity As...

Page 82: ...rminal display can only be configured if its telephone jack is connected to the I O control module in the electric box and power is turned on The factory default value for the display terminal address...

Page 83: ...g the correct terminal address press the Enter key once to confirm your selection A message NO LINK will appear At this point the terminal has been set with the correct address for the controller and...

Page 84: ...ss you can examine the entire network setup Press the group setup keys up arrow down arrow and Enter together as done to access the Address Configuration screen but continue holding after the Address...

Page 85: ...screen by pressing the Prg key and scrolling through the menu selections until the word Factory appears in the center of the screen Figure 4 80 Factory Group screen Press the Enter key twice and you...

Page 86: ...tal in Network Enter the total number of A C units in the group 0 to 9 1 Min Number Active Enter the total number of active A C units in the group 0 to 9 1 Enb lead override If set to yes you may manu...

Page 87: ...ifies the duty of the A C unit by displaying the variable number assigned in Factory Group screen 1 0 Out of Service 1 Active 2 Standby etc 0 to 6 0 Figure 4 84 Factory Group Capacity Assist Screen 3...

Page 88: ...nit to respond to the Group sensors 0 No 1 Yes Yes Static Pr Sensor 0 No 1 Yes Yes Figure 4 87 Factory Group Group Alarm Setup Screen 6 This screen may be accessed on the controller for each unit to b...

Page 89: ...m 1 4 0 4 Circuit 1 high pressure 8 0 5 Circuit 1 low pressure 16 0 6 DX lockout 32 0 7 Humidifier lockout 64 0 8 FC AWS lockout 128 0 Table 4 18 Group alarms 9 to 16 Number Description Bitmask Defaul...

Page 90: ...mperature CW1 16 0 22 Low water temperature CW1 32 0 23 Reserved 64 0 24 Reserved 128 0 Table 4 20 Group alarms 25 to 32 Number Description Bitmask Default 25 Upper temperature sensor 1 0 26 Middle te...

Page 91: ...fire smoke detection loss of all cooling all CW valves or loss of airflow Figure 4 88 Factory Group Group Status Screen 7 The Factory Group Screen 7 provides an overview of pLAN workgroup Table 4 22...

Page 92: ...Display indicates how many units in the group are not available to operate 0 The final step to configure a workgroup is to access the Service Options Group Setup screens used to configure parameters...

Page 93: ...apacity assist operation The values entered are offsets which are applied to the control setpoints Each unit in the group should be assigned incrementally increasing decreasing offsets for cooling hum...

Page 94: ...s to be the Lead Average Min or Max values The selections made in this screen will affect all the controllers in the workgroup no matter which controller you access the screen from 4 6 2 7 5 Group Ave...

Page 95: ...on 4 6 2 6 4 6 2 8 3 Lead Controller Group Sensors This screen appears only in the display of the controller that is designated as the lead in a multi unit workgroup The lead controller polls the temp...

Page 96: ...it has failed 4 7 BMS Communications When BMS communications are used the controller must be equipped with an optional expansion card designed for one of a variety of serial communications protocols a...

Page 97: ...up the parameters to allow a BMS BAS interface for monitoring controller operation for the serial based networks such as BACnet MS TP Units using the BACnet over IP BACnet over Ethernet or HTTP protoc...

Page 98: ...ing Table 4 26 I O control module signal LEDs Red LED Yellow LED Green LED Description Application with error or no pLAN table Application with error or no pLAN table Controller connected to ONLY one...

Page 99: ...hernet 10 Mbps 10BASE T RJ 45 direct unit connection Uses BMS addresses HTTP 10 Mbps 10BASE T RJ 45 direct unit connection Uses BMS addresses SNMP V1 V2c 10 Mbps 10BASE T RJ 45 direct unit connection...

Page 100: ...n speed 0 0 R 10 011 10 Middle fan manual speed 0 0 R W 11 012 11 Upper fan manual speed 0 0 R W 12 013 12 Lower fan manual speed 0 0 R W 13 014 13 Static pressure sensor current value 0 0 R 14 015 14...

Page 101: ...d bit for BMS digital outputs 0 R 13 142 1013 Packed bit for BMS digital outputs 0 R 15 144 1015 Prop humidifier control output 0 R 16 145 1016 Head pressure control output 0 R 100 229 1100 BMS keep a...

Page 102: ...P Modbus Coils Binary Values for BACnet Table 4 31 Boolean Values for HTTP SNMP Modbus Coils Binary Values for BACnet BMS Address Modbus Address BACnet Address Description Default Direction 1 002 1 Gl...

Page 103: ...ature Reserved 4 Filter Low temperature Reserved 5 Fire Smoke High humidity Reserved 6 Water detection Low humidity Reserved 7 Condensate pan High water temp CW1 Reserved 8 Moisture Low water temp CW1...

Page 104: ...ature Reserved 2 Lower temperature Reserved 3 Return temperature Reserved 4 Return humidity Reserved 5 Static air pressure Reserved 6 Suction pressure Reserved 7 Suction temperature Reserved 8 Dischar...

Page 105: ...m 2 1 Customer alarm 1 Customer alarm 3 2 Water Reserved 3 Condensate pan Reserved 4 Humidifier Reserved 5 Moisture Reserved 6 Middle fan alarm Reserved 7 Upper fan alarm Reserved 8 Fire smoke Reserve...

Page 106: ...two categories Variables like the temperature setpoint are permanent As permanent variables they retain their value regardless of power loss or BMS communications failure The controller s flash memory...

Page 107: ...R W 102 231 1102 BMS run fan speed for CW units 0 R W 103 232 1103 BMS dehum fan speed for CW units 0 R W 4 9 9 Boolean Values for HTTP SNMP Modbus Coils Binary Values for BACnet Table 4 37 Boolean V...

Page 108: ...ectric box at the motor start protectors and circuit breakers even with the unit turned off at the microprocessor controller To isolate the unit for maintenance turn off power at the main power discon...

Page 109: ...anable filters Clean the filter media using a vacuum cleaner low pressure compressed air or rinse with water A mild detergent such as dishwashing liquid may be used DO NOT use solvents or cleaning age...

Page 110: ...ed semi annually and cleaned as required following standard coil cleaning practices Using a brush clean the coil fins of all debris that will inhibit airflow This can also be done with compressed air...

Page 111: ...ocedures unless the procedure specifically requires the system to operate For troubleshooting purposes the system may be operated with the doors open by using a pair of channel lock pliers to turn the...

Page 112: ...tor Repair or replace f No control signal to fan s Check the control I O board for a 0 10 VDC control signal to the fan s Refer to the electric drawing to determine the correct I O board terminal numb...

Page 113: ...mpt to make repairs without the proper tools 5 3 1 CW System If the Chilled Water system isn t cooling or if cooling is reduced check for leaks in the system Check for clogged water lines If filters a...

Page 114: ...el will repeatedly flash four times indicating that the cylinder is completely used and a replacement cylinder must be installed The cylinder is disposable and cylinder life is dependent on water supp...

Page 115: ...he cable tie to release it Lift the cylinder straight up to disengage it from the humidifier 12 Place the new cylinder on the side mounting slots within the unit ensuring the cylinder mounting stubs a...

Page 116: ...old pump was removed reversing the procedure 5 3 2 2 Fan Replacement The EC Fans are located behind the front access panel The panel must be removed to access the fans The fans are equipped with quic...

Page 117: ...move the mounting bracket from the old fan and install it on the new fan Bolt the new fan assembly together with the inlet ring into the cabinet and plug the power and control cables into the connecto...

Page 118: ...the barbed stub fitting Release the cable retaining clip on the side of the pump and cut the wire ties holding the cable loop Maneuver the pump into the fan opening with the cable still attached and r...

Page 119: ...d service technician to determine the defect of the part If it is determined that the part may be defective a replacement part will be sent A written or faxed purchase order is required on warranty pa...

Page 120: ...nt parts If the returned part is not a stocked item a 50 restocking charge may be applied Additionally a Return Material Authorization Number is required when returning parts To receive credit for ret...

Page 121: ...ut off valve is installed open valve 7 Humidifier On Off Drain switch is in On position 8 Filters installed 9 Incoming line voltage matches equipment nominal nameplated rating tolerances 10 Main power...

Page 122: ...pump Clean the inside unit as necessary Tighten electrical connections Annually Chilled water systems Inspect chilled water system for leaks and corrosion Conduct a complete check of all services list...

Page 123: ...conditioning refrigeration HP Horsepower Hz Hertz IAQ Indoor air quality KVA Kilo Volt Amps kW Kilowatt LRA Locked rotor amps MAX CKT BKR Maximum circuit breaker MAX FUSE Maximum fuse MCA Minimum circ...

Page 124: ...724 746 5500 blackbox com Page 124 Appendix B Glossary Definition of Terms and Acronyms VDC Volt direct current WG Water Glycol...

Page 125: ...724 746 5500 blackbox com Page 125 NOTES...

Page 126: ...724 746 5500 blackbox com Page 126 NOTES...

Page 127: ...724 746 5500 blackbox com Page 127 NOTES...

Page 128: ...protection products to media converters and Ethernet switches all supported by free live 24 7 Tech support available in 30 seconds or less Copyright 2013 Black Box Corporation All rights reserved Bla...

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