Liebert Mini-Mate2 MCD24A User Manual Download Page 61

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System Performance Microprocessor Controls

Liebert

Mini-Mate2

™

7.0

YSTEM

ERFORMANCE

ICROPROCESSOR

ONTROLS

This section provides a detailed description of how the Liebert Mini-Mate2 responds to operator

inputs and room conditions.

7.1

Temperature Control

7.1.1 Cooling/Heating Required

The temperature control program for the microprocessor is based on a calculated percentage

requirement for cooling/heating.

7.1.2 Cooling Operation (Cooling, Compressorized Direct Expansion and Chilled Water)

Cooling is ACTIVATED when the temperature control calculates a requirement for cooling of 100%. It

is DEACTIVATED when the cooling requirement drops below 50%. The optional hot gas bypass is

energized when a call for cooling occurs, unless there is also a call for dehumidification.

Table 27

Cooling and dehumidification load response of hot gas bypass

Situation

Response

Cooling only

Dehumidification only

OFF

Cooling with Dehumidification

OFF

Summary of Contents for Mini-Mate2 MCD24A

Page 1: ...Precision Cooling For Business Critical Continuity Liebert Mini Mate2 User Manual 2 3 Tons 50 60Hz ...

Page 2: ......

Page 3: ...3 Sensors 9 3 4 Switches and Motors 9 3 5 Free Cooling 10 3 6 Optional Configurations Prop Fan Condensing Units 10 3 7 Optional Configurations Water Glycol Condensing Units 10 3 8 Optional Configurations Chilled Water Units 10 4 0 SHIP LOOSE ACCESSORIES FIELD INSTALLED 11 4 1 Remote Monitoring Autochangeover and Leak Detection Equipment 12 5 0 SITE PREPARATION AND INSTALLATION 13 5 1 Installation ...

Page 4: ...pleted Installation 42 6 0 MICROPROCESSOR CONTROL 43 6 1 Feature Overview 43 6 2 Main Menu Menu 44 6 3 Setpoints 44 6 4 Status 45 6 5 Active Alarms 45 6 6 Time 45 6 7 Date 45 6 8 Setback 45 6 9 Setup Operation 46 6 9 1 Restart Time Delay 46 6 9 2 C F Degrees 46 6 9 3 Humidity Control Method 46 6 10 Change Passwords 46 6 11 Calibrate Sensors 47 6 12 Alarm Enable 47 6 13 Alarm Time Delay 47 6 14 Com...

Page 5: ... 8 2 2 High Temperature Sensor 58 8 2 3 Smoke Detected 58 9 0 SYSTEM TESTING AND MAINTENANCE 59 9 1 System Testing 59 9 1 1 Environmental Control Functions 59 9 1 2 Cooling 59 9 1 3 Heating 59 9 1 4 Humidification 59 9 1 5 Dehumidification 59 9 1 6 High Temperature Sensor Optional 59 9 1 7 Smoke Detector Sensor 59 9 1 8 Remote Shutdown 59 9 2 Maintenance 60 9 2 1 Electric Panel 60 9 2 2 Filters 60...

Page 6: ... belt drive blower assembly 25 Figure 15 Evaporator and chilled water unit piping data 26 Figure 16 Evaporator and chilled water unit electrical connections 29 Figure 17 Close coupled installation 30 Figure 18 Indoor air cooled centrifugal condenser dimensions and pipe connections 32 Figure 19 Centrifugal condenser electrical connections 33 Figure 20 Cabinet and floor planning dimensional data out...

Page 7: ... sizes and torque 23 Table 15 Net weights evaporator and chilled water units 24 Table 16 Net weight high static blower module 25 Table 17 Indoor condensing unit airflow CFM at 0 5 iwg esp 31 Table 18 Centrifugal condenser dimensions weights 32 Table 19 Dimensions and net weights air cooled outdoor condensing units 35 Table 20 Net weight indoor water glycol cooled condensing unit 37 Table 21 View d...

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Page 9: ... unit contains live high voltage The only way to ensure that there is NO voltage inside the unit is to install and open a remote disconnect switch and check the internal power supply wires with a voltmeter Refer to unit electrical schematic Follow all applicable local and national electric codes WARNING Risk of explosive discharge from high pressure refrigerant Can cause injury or death This unit ...

Page 10: ...ble to fit below the skid and or unit to prevent exterior and or underside damage NOTICE Risk of improper storage Can cause unit damage Keep the Liebert Mini Mate2 upright indoors and protected from dampness freezing temperatures and contact damage CAUTION Risk of leaking water Can cause equipment and building damage This unit requires a water drain connection It may also require an external water...

Page 11: ...R Remote Humidifier Contact J Canister Humidifier and Remote Humidifier Contact Reheat Type 0 No Reheat E Electric Reheat S SCR Reheat not available with free cooling Sensor Packages 0 None A Filter Clog B Smoke Sensor C High Temperature Sensor D Filter Clog Smoke Sensor E Filter Clog High Temperature Sensor F Smoke Sensor High Temperature Sensor G Filter Clog Smoke Sensor High Temperature Sensor ...

Page 12: ...Liebert Lee Temp 0 Std Sound Level Z Quiet Line Standard Coil C Coated Coil Cooling Method A Air Cooled Refrigerant 7 R 407C MC D Disconnect Switch 0 No Disconnect Switch MC Liebert Mini Mate2 indoor condensing units Refrigerant 7 R 407C H Hot Gas Bypass D 38 2 A H 7 Head Pressure Controls 2 2 Way Standard Pressure Water Reg Valve 3 3 Way Standard Pressure Water Reg Valve D 2 Way High Pressure Wat...

Page 13: ... 50Hz 40 3 ton 60Hz A D Valve Type 2 2 Way Chilled Water Valve 3 3 Way Chilled Water Valve Supply Power P 208 230V 1 ph 60Hz X 277V 1ph 60Hz S 220V 1ph 50Hz A 460V 3ph 60Hz Y 208 230V 3ph 60Hz M 380 415V 3ph 50Hz Humidification H Canister Humidifier 0 No Humidifier R Remote Humidifier Contact J Canister Humidifier and Remote Humidifier Contact Sensor Packages 0 None A Filter Clog B Smoke Sensor C ...

Page 14: ...s or optional sweat adapters for field refrigerant piping Easy to Service Low maintenance components are easily accessed through removable front panels Spare parts are always in Emerson inventory and available on short notice Advanced Control Technology A menu driven microprocessor control system provides precise temperature and humidity control and accurate alarm setpoints Using touch sensitive b...

Page 15: ...and liquid line solenoid valve Unit must be mounted indoors Condensing unit is designed to use outdoor air with temperatures ranging from 30 F to 95 F 34 C to 35 C 2 2 2 Outdoor Prop Fan Condensing Units Outdoor Prop Fan Condensing Units include scroll compressor condenser coil R 407C unit charge prop fan liquid line solenoid valve high pressure switch Liebert Lee Temp head pressure control and ho...

Page 16: ...rature humidity setpoints sensitivities fan speed and alarm conditions The wall box is field wired to the microprocessor control using standard four conductor thermostat wire field supplied The temperature and humidity sensors are in the wall box which can be installed up to 300 feet 91 4m from the evaporator unit The unit mounted control board also includes common alarm terminals and shutdown ter...

Page 17: ...nal humidifier 3 3 Sensors Smoke Sensor checks return air shuts down the unit upon sensing smoke and activates visual and audible alarms at the wall box display This smoke sensor is not intended to function as or replace any smoke sensor system that may be required by local or national codes High Temperature Sensor senses the return air temperature and shuts down unit if the temperature reaches 12...

Page 18: ...og capacities at ambient temperatures up to 95 F 35 C Condenser coils can be phenolic coated for extended coil life in coastal areas 3 7 Optional Configurations Water Glycol Condensing Units Indoor Water Glycol Condensing Units are also available with the following piping options Two way water reg valve with 350 psi 2413kPa design pressure Three way water reg valve with 150psi 1034kPa design press...

Page 19: ...igh condensate level A Remote Temperature and Humidity Sensor package includes sensors in an attractive case with 30 ft 9 m of cable Can be wall or duct mounted Remote sensors should be used when the wall box is not located in the space to be conditioned Field Installed Kits available for filter clog smoke sensor high temperature sensor electric reheat and humidifier The kits include installation ...

Page 20: ... Environmental DO interface cards in one enclosure for installation external to the Liebert Mini Mate2 The self contained kit includes an external 120VAC to 24VAC power transformer Wiring harnesses are not provided Power and communication wiring is field provided The Liebert Liqui tect 410 Point Leak Detection Sensor detects the presence of conductive liquid using a pair of corrosion resistant gol...

Page 21: ...configurations 50Hz Nominal Capacity Cooling Unit Condensing Unit Indoor Air Cooled Centrifugal fan Outdoor Air Cooled Propeller Fan Indoor Remote Water Glycol Cooled 3 Tons MM_35E MC_35A PFH_36A MC_37W MM_39C Self Contained Chilled Water Table 3 Application limits evaporator and chilled water units Input Voltage Range of Return Air Conditions to Unit Minimum Maximum Dry Bulb Temperature Relative ...

Page 22: ... noise Avoid locating the unit in an alcove or at the extreme end of a long narrow room Avoid installing multiple units close to each other This could result in crossing air patterns uneven loads and competing operating modes When installing an air cooled or water glycol cooled unit inside a space ensure that national and local codes are met for refrigerant concentration limits that might vary wit...

Page 23: ... System Evaporator Supply and Return Air Ducted Outdoor Air Cooled Condensing Unit Split System Evaporator Supply and Return Air Ducted Remote Water Glycol Condensing Unit Split System Evaporator Supply and Return Air Plenum Remote Water Glycol Condensing Unit Split System Evaporator Supply and Return Air Ducted Remote Water Glycol Condensing Unit Condensing Unit Evaporator Drycooler Condensing Un...

Page 24: ...nd local codes Use field supplied threaded suspension rods and 3 8 16 factory hardware kit Recommended clearance between ceiling grids and building structural members is unit height plus 3 in 76mm Install the four field supplied rods by suspending them from suitable building structural members Locate the rods so that they will align with the four mounting holes in the flanges that are part of the ...

Page 25: ...se coupled hang each unit before connecting them together Align four bolt holes in the condensing unit with cage nuts in the evaporator Insert rubber spacers and secure with provided hardware Align the refrigerant connections and tighten them as described in 5 5 3 Piping Connections and Coolant Requirements see Figure 17 Close coupled installations may take advantage of a single point power kit to...

Page 26: ...with local and national codes 5 5 3 Piping Connections and Coolant Requirements The following pipe connections are required A drain line from the evaporator coil drain pan This line also serves as the drain for the optional humidifier A drain line from the secondary drain pan beneath the unit A water supply line to the optional humidifier if applicable Refrigerant piping connections between the ev...

Page 27: ...gainst stop shoulder and thread nut to body hand tight 4 With proper wrench tighten 1 1 4 to 2 1 4 turns NOTICE Risk of improper tightening of the piping fittings Can cause fitting damage and leaks that can result in building and equipment damage Do not over tighten the piping fittings Chilled Water Loop On chilled water units install manual service shutoff valves at the supply and return lines of...

Page 28: ...practices Refrigerant R 407C Loop All split systems require two refrigerant lines an insulated copper suction line and a copper liquid line between the evaporator and the condensing unit The refrigerant lines can be piped by installing an optional sweat adapter kit and hard piping between the two units optional pre charged line sets maximum combined length of 45 13 7m close coupling the units toge...

Page 29: ...k Connect Fittings on page 23 for the proper procedure to connect lines to each unit of the split system 8 Add refrigerant R 407C to the completed system as calculated per Table 10 for both liquid and suction line sizes used When installing remote condensing units above the evaporator the suction gas line should be trapped at the evaporator This trap will retain refrigerant oil during the Off cycl...

Page 30: ...Emerson Application Engineering for assistance Table 10 Line charges refrigerant per 100 ft 30m of Type L copper tube Line Size O D in R 407C lb 100 ft kg 30m Liquid Line Suction Line 3 8 3 7 1 7 1 2 6 9 3 1 5 8 11 0 5 0 0 4 0 2 3 4 15 7 7 1 0 6 0 3 7 8 23 0 10 4 1 0 0 4 1 1 8 1 7 0 7 1 3 8 2 7 1 1 Table 11 Refrigerant charge in Liebert pre charged R 407C line sets Line Size in Length ft m Charge ...

Page 31: ...the proper size wrench until the coupling bodies bottom out or until a definite resistance is felt 6 Using a marker or pen make a line lengthwise from the coupling union nut to the bulkhead 7 Tighten the nuts an additional quarter turn the misalignment of the lines shows how much the coupling has been tightened This final quarter turn is necessary to insure that the joint will not leak Refer to Ta...

Page 32: ...yp 2 each end Note Unit is spaced evenly in reference to threaded rod centers 1 7 16 37mm 1 7 16 37mm 14 356mm Removable Access Panels 27 13 16 706mm Threaded Rod Centers Cabinet Outline Removable panel on side of plenum Minimum clearance 30 762mm for filter access and removal Air Discharge out sides of plenum Air Discharge out sides of plenum Cover Plate Supplied With Plenum Air Inlet through gri...

Page 33: ... 4 29 32 125mm Cabinet to Cabinet 4 29 32 125mm Threaded Rod To Threaded Rod 57 13 16 1468mm Overall Dimension 55 13 16 1418mm Threaded Rod Centers 54 1372mm Cabinet Dimension High Static Blower Module Evap Unit 30 762mm Blower Box Dimension 5 7 8 149mm 29 7 8 759mm Threaded Rod Centers 3 7 32 82mm Base to Base 14 356mm Outlet Dimension 6 7 8 175mm 6 5 16 160mm Outlet 9 3 4 Outlet 248mm 16 13 16 4...

Page 34: ... Valve Power Supply from Electric Service Power Block in Fan Coil Module Fan Coil Unit Fan Coil Unit Air Outlet Duct Drain Line Field Supplied Drain Line Field Supplied Condensate Pump 3 4 Hose Barb Supplied on Pump Tank 3 4 Hose Barb Supplied on Pump Tank Flexible Rubber Tubing Flexible Rubber Tubing 3 4 FPT Customer Connection Field Supplied Rigid Piping Support as Required Field Supplied Rigid ...

Page 35: ... unit 12 Run the unit to make sure the pump works properly Operate the pump and check the drain line and discharge line for leaks Correct as needed 5 5 5 Electrical Connections Each unit is shipped from the factory with internal wiring completed Refer to electrical schematic when making connections Electrical connections to be made at the installation site are Power supply to each ceiling unit Con...

Page 36: ...evaporator before installing the unit in the ceiling See Figure 17 Specific installation instructions are included with the single point power kit Control Connections A field supplied 4 wire control connection 24 VAC is required between the evaporator and the condensing unit Control wiring must be installed in accordance with the National Electrical Code NEC Class 2 circuit Glycol cooled units als...

Page 37: ... 1 wire Optional condensate pump aux float switch connection to term TB1 8 TB1 9 Field supplied unit disconnect switch when factory unit disconnect switch is not supplied Factory installed disconnect switch Electric service not by Emerson Entrance for Customer High Voltage Connections Entrance for Customer Low Voltage Connections Drycooler Circulating pump control circuit TB70 71 Optional w Econ O...

Page 38: ...k areas Refer to Table 9 for maximum refrigerant line lengths To mount the unit in the ceiling refer to 5 5 Installing the Ceiling Units 5 6 2 Electrical Connections Refer to 5 5 5 Electrical Connections for general wiring requirement and cautions Refer to the unit s electrical schematic when making connections Refer to the unit s specifications for full load amp and wire size amp ratings Close Co...

Page 39: ... structure For multiple unit installations space the units so that the hot condensing unit exhaust air is not directed toward the air inlet of an adjacent unit Considerations for Specific Applications In applications where the ceiling plenum is used as the heat rejection domain the discharge air must be directed away from the condensing unit air inlet and a screen must be added to the end of the d...

Page 40: ...utlet Duct Dimension Duct Flange 2 1 4 57mm 1 25 4mm 20 7 16 519mm Coil Inlet DuctConn MinimumClearance 33 838mm This End for Component Access and Removal 20 3 4 527mm 1 2 13mm 7 8 22 2mm Dia Electrical Entrance for Low Voltage Connection Suction Line Liquid Line Male Quick Connect Male Quick Connect Note Unit is evenly spaced in reference to threaded rod centers DIMENSIONAL DATA Blower Motor Serv...

Page 41: ...tory wired to components on electric panel Single or three phase electric service not by Liebert Connection terminal for field supplied earth grounding wire Low voltage electric power supply entrance DPN000207 Rev 2 Heat rejection connection Field supplied 24V NEC Class 2 wiring See note 2 Wire connections from evaporator mod 1 24V GRD 2 24V Supply 3 High Pressure Alarm OPT 4 Hot Gas Bypass Connec...

Page 42: ...hs Install a solid base capable of supporting the weight of the condensing unit The base should be at least 2 inches higher than the surrounding grade and 2 inches larger than the dimensions of the condensing unit base For snowy areas a base of sufficient height to clear snow accumulation must be installed Figure 20 Cabinet and floor planning dimensional data outdoor condensing unit NOTE Follow al...

Page 43: ...r maintenance A transformer is available for 277 VAC single phase applications 2 and 3 ton Control Connections Field supplied control wires must be connected between the evaporator and the condensing unit See Figure 16 and the electrical schematic on the units for more details Four wires are required between the evaporator and condensing unit Table 19 Dimensions and net weights air cooled outdoor ...

Page 44: ... electrical and plumbing codes DPN000191 Rev 2 Condenser Coil High Pressure Switch Scroll Compressor Hot Gas Bypass Solenoid Valve Hot Gas Bypass Control Valve 3 8 SAE 45 Male Flare MCD or Atmospheric PFH Pressure Relief Valve Check Valve Sight Glass Lee Temp Receiver Liquid Line Solenoid Valve Liquid Injection Valve Bulb Suction Line Male Quick Connect Coupling 3 Way Head Pressure Relief Valve Li...

Page 45: ...verall Cabinet Dimension 8 7 8 225mm 50 1 4 1276mm Overall Dimension 48 1 4 1225mm Threaded Rod Centers 46 1 2 1181mm Cabinet Dimension 20 3 4 527mm Note Unit is spaced evenly in reference to threaded rod centers DIMENSIONAL DATA Cabinet Dimension 7 8 22mm Dia Electrical Entrance for High Voltage Connection 7 8 22 2mm OD CU Water Glycol Outlet Connection Extends 3 1 2 88 9mm beyond panel exterior ...

Page 46: ...lation of the unit When the condensing unit fluid quality is poor filters that can be easily serviced should be placed in the supply line These filters extend the service life of the condensing unit Condensing Unit Fluid Requirements The maximum fluid pressure is 150 PSI standard pressure and 350 PSI for high pressure units refer to unit nameplate and model number description page at beginning of ...

Page 47: ...Valve Fluid Return From Unit Fluid Return From Unit 3 Way Water Regulating Valve Optional Suction Line Female Quick Connect Coupling Liquid Line Female Quick Connect Coupling Sensing Bulb Service Access Ports Filter Drier Evaporator Coil Expansion Valve FIELD PIPING FACTORY PIPING Use Liebert sweat adapter kit with field hard piping or use Liebert pre charged line set Close coupling option availab...

Page 48: ...ing coil outlet can be field piped to the condensing unit inlet provided a 3 way regulating valve has been installed within the water glycol condensing unit see Figure 24 Figure 24 Optional free cooling coil 3 way valve on water glycol units NOTE If the free cooling coil is piped to an open water tower a CU NI copper nickel type coil must be ordered to prevent corrosion of the copper tubes or a he...

Page 49: ...ve opens upon a call for reheat Figure 25 Optional hot water reheat two way valve Shutoff Valves Hose Bibs Bleed Valve Hot Water Reheat Control Valve Water Return From Unit Water Supply To Unit Y Strainer Hot Water Reheat Coil DPN000197 Rev 2 Components are not supplied by Liebert but are recommended for proper circuit operation and maintenance FIELD PIPING FACTORY PIPING NOTE Hot water reheat onl...

Page 50: ... 12 Line voltage to power wiring matches equipment nameplate ___ 13 Power wiring connections completed between disconnect switch evaporator and condensing unit including earth ground ___ 14 Power line circuit breakers or fuses have proper ratings for equipment installed ___ 15 Control wiring connections completed to evaporator and condensing unit if required including wiring to wall mounted contro...

Page 51: ...Silence Help If an alarm is present pressing this key will silence he alarm If this key is pressed when no alarms are present help text will appear bottom near left Down Arrow Decreases the value of displayed parameter while in a set mode bottom near right Enter ENTER After setting a control point press Enter to store the information in the microprocessor bottom far right Figure 26 Control key loc...

Page 52: ...lue When the value has been changed press Enter to store the value For example to change the temperature setpoint from the main status display 1 Press the Menu key to display the main menu 2 Scroll to SETPOINTS using the Up Down arrow key Press the Enter key 3 Scroll to TEMP SETPOINT using the Up Down arrow key Press the Enter key 4 Use the Up Down arrow to change the value Press the Enter key SET...

Page 53: ...elect the function then use the Up Down arrow to change the first character press Enter to store then press the Up Down arrow to change the section character press Enter to store etc THERE IS A BATTERY BACKUP FOR THE DATE AND TIME FEATURES 6 7 Date The controller date must be set to allow for the setback control To change the date press Enter then use the Up Down arrow to change the first characte...

Page 54: ...ion can result when overcooling occurs during a dehumidification cycle This is due to a higher than normal RH reading caused by overcooling the room about 2 RH for each degree of overcooling This drop in temperature extends the dehumidification cycle Later when the dehumidification ends and the temperature rises to the setpoint the RH reading falls The final RH reading will then be lower than actu...

Page 55: ...med with a time delay causing the unit to delay a specified amount of time 0 255 seconds before recognizing the alarm See Table 24 for the default times The alarm condition must be present for the full amount of the time delay before the alarm will sound If the alarm condition is diverted prematurely the alarm will not be recognized and the time delay time will automatically reset 6 14 Common Alar...

Page 56: ... Text can be up to 20 characters in length and can be either a blank space or any of the following alphanumeric characters and symbols A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 1 2 3 4 5 6 7 8 or 9 Use the Up Down Arrows to select a character then press Enter The cursor will move to the next space where you may once again use the Up Down Arrows to select another character etc LCD Contr...

Page 57: ...Enable Humidifier Disable Humidifier 7 Enable Dehumidifier Disable Dehumidifier 8 Electric Reheat Gas Reheat Table 26 Switch settings wall box board Switch OFF Position ON Position 1 Disable Beeper Enable Beeper 2 Not Used Must remain in OFF position 3 Not Used Must remain in OFF position 4 Not Used Must remain in OFF position 5 Not Used Must remain in OFF position 6 Compressor on continuously for...

Page 58: ... next the previous load is automatically turned Off The loads can also be toggled on off by selecting ENTER Once turned on the output will remain on for five minutes unless toggled off or the test outputs function is exited by selecting MENU ESC Compressor is limited to 15 seconds on to prevent damage NOTICE Risk of overheating the compressor during the Test Outputs mode Can cause compressor damag...

Page 59: ...ime 2 Wknd Temp 2 Wknd Tsens 2 Wknd Humd 2 Wknd Hsens 2 Wkdy Temp 1 Wkdy Tsens 1 Wkdy Humd 1 Wkdy Hsens 1 Wkdy Time 2 Wkdy Temp 2 Wkdy Tsens 2 Wkdy Humd 2 Wkdy Hsens 2 Setup Operation Restart TD C F Degrees Humidity Control Dipswch 00000000 Pos 12345678 Setpoint Password Enter New PSW Setpt PSW 000 Diagnostics Test Inputs Test Outputs Test Microcontroller Custom Text Custom Text 1 Custom Text 2 Cu...

Page 60: ...ion Common TB2 1 Heat Rejection TB3 4 Connection to TB3 Pin 4 of wall box TB1 9 Condensate Pump Aux Alarm TB3 3 Connection to TB3 Pin 3 of wall box TB1 8 Condensate Pump Aux Alarm TB3 2 Connection to TB3 Pin 2 wall box TB1 7 Common Alarm Connection TB3 1 Connection to TB3 Pin 1 of wall box TB1 6 Common Alarm Connection TB4 2 Site Monitoring Connection TB1 5 Remote Shutdown TB4 1 Site Monitoring Co...

Page 61: ...ed percentage requirement for cooling heating 7 1 2 Cooling Operation Cooling Compressorized Direct Expansion and Chilled Water Cooling is ACTIVATED when the temperature control calculates a requirement for cooling of 100 It is DEACTIVATED when the cooling requirement drops below 50 The optional hot gas bypass is energized when a call for cooling occurs unless there is also a call for dehumidifica...

Page 62: ...en LED indicates that the reheat is operating properly A red LED indicates that the reheat has failed and both the reheat element and GCD need to be replaced Figure 30 Ground current detector WARNING Do not remove or disable the ground current detector Failure to leave the GCD in place could result in smoke or fire WARNING Risk of heater element failure smoke and fire Can cause building and equipm...

Page 63: ...y operating the compressor without the hot gas bypass active On cooling units with direct drive motors the fan will operate at low speed unless the cooling requirement reaches 100 At that point the low speed fan is disabled unless manually overridden by the user until the cooling requirement decreases to 0 Dehumidification will also be disabled if the heating requirement exceeds 125 It will be re ...

Page 64: ...VICES AND WIRING MAY BE REQUIRED AT THE FACTORY FOR SOME OF THE ALARMS 8 1 1 Custom Alarms Custom alarm s messages are programmed at the LCD The message displayed may be included in a list of provided alarms or it may be customized text for up to 2 alarms IF CUSTOMIZED TEXT IS USED MAINTENANCE PERSONNEL SHOULD BE INFORMED OF THE ALARM FUNCTION AND THE REQUIRED ACTION 8 1 2 High Head Pressure Compr...

Page 65: ...ons High The room return air temperature increases to the high temperature alarm set point Check for proper set point value Is the room load more than the unit can handle i e capacity too small Make sure cooling components are operating compressor or valves Low The room return air temperature decreases to the low temperature alarm set point Check for proper set point value Make sure all heating co...

Page 66: ...ement is necessary A differential air pressure switch closes when the pressure drop across the filters becomes excessive The switch is adjustable using the procedure on the switch label 8 2 2 High Temperature Sensor The optional high temperature sensor feature is a bimetal operated sensing device with a closed switch under normal conditions Connected between pins 1 8 and 1 9 this device will shut ...

Page 67: ...mpletion of testing return the humidity set point to the desired humidity 9 1 5 Dehumidification The dehumidification performance can be tested by setting the humidity set point at R H 10 below room relative humidity On cooling units with direct drive motor the compressor should turn on and the fan should switch to low speed Upon completion of testing return humidity set point to the desired humid...

Page 68: ...the unit s motor bearings are permanently sealed and self lubricating they should be inspected monthly for signs of wear For units with the optional belt drive motor blower the drive belt should be checked monthly for signs of wear and proper tension Pressing on belts midway between the sheave and pulley should produce from 1 2 to 1 12 to 25mm of deflection Belts that are too tight can cause exces...

Page 69: ...scharge pressure will vary greatly with load and ambient conditions see Table 29 The high pressure switch will shut the compressor down at its cut out setting Thermostatic Expansion Valve The thermostatic expansion valve keeps the evaporator supplied with enough refrigerant to satisfy load conditions Proper valve operation can be determined by measuring superheat level If too little refrigerant is...

Page 70: ...lp to establish a pattern of depletion A visual inspection of the solution and filter residue is often helpful in judging whether or not active corrosion is occurring The complexity of problems caused by water requires expert advice from a water treatment specialist plus a regular maintenance program schedule It is important to note that improper use of water treatment chemicals can cause more sev...

Page 71: ...erature is required Adjust no more than 1 4 turn at a time Let the system stabilize for 15 minutes before determining if additional adjustment are necessary 5 After obtaining the suction pressure required reinstall cap tightly making sure there are no leaks 6 Let the evaporator operate for approximately 10 to 15 minutes to make sure the suction pressure is within the range desired 7 There may be a...

Page 72: ... which is factory set at 60 seconds During this repeating time cycle the fill valve will open periodically to replenish the water being boiled off and maintain a steady state output at the setpoint The amperage variance will depend on the conductivity of the water 4 After a period of time the mineral concentration in the canister becomes too high When this occurs the water boils too quickly As the...

Page 73: ...odic maintenance inspections by alert service personnel i e identification of abnormal operation can be a major factor in reducing maintenance costs It is easier and more cost effective to implement the necessary preventative steps that ensure proper system operation rather than ignore a problem until it results in compressor failure and costly replacement When troubleshooting a compressor problem...

Page 74: ...ry nitrogen through the piping during brazing to prevent formation of copper oxide scale inside the piping Copper oxide forms when copper is heated in the presence of air POE oil will dissolve these oxides from inside the copper pipes and deposit them throughout the system clogging filter driers and affecting other system components A pure dry nitrogen flow of 1 3 ft3 min 0 5 1 5 l s inside the pi...

Page 75: ...ving any wires Refer to schematic on unit Slide the rubber boot back to expose the connections Remove the two 2 power wires and the canister full wire Do not loosen the screws that secure the electrodes 7 Loosen the steam outlet hose clamps and slide the steam hose away from the canister fitting Release the canister clamp along the base of the canister 8 Remove the canister 9 Reverse previous step...

Page 76: ...or mineral deposits ___ 2 Check condition of electrodes ___ 3 All hoses and fittings tight ___ 4 Check water make up valve for leaks Fan Section Drain Lines ___ 1 Impellers free of debris ___ 2 Bearings in good condition ___ 1 Check for obstructions and sediment build up ___ 2 Check for external damage and or corrosion ___ 3 Check for leaks Compressor Section Flood Back Head Pressure Control if ap...

Page 77: ...frigerant charge Check pressure gauges See Table 11 and Table 13 for recommended pressures At low ambient temperatures proper refrigerant charge is very important on units with Lee Temp receivers Compressor high head pressure Insufficient air flow across condenser coil Remove debris from coil and air inlets Water Glycol cooledonly No fluid flowing through condenser Check fluid supply to regulating...

Page 78: ... control can be reset by cycling power from the disconnect switch Condensate pump does not operate Open or short circuit in wiring Find open or short circuit and repair power to pump Continuous Cooling Failed temperature sensor Temperature display will indicate dashes Check wiring from temperature humidity board remote sensors to the control board or from control board to wall box Replace temperat...

Page 79: ......

Page 80: ... change without notice Liebert is a registered trademark of Liebert Corporation All names referred to are trademarks or registered trademarks of their respective owners Technical Support Service Web Site www liebert com Monitoring liebert monitoring emerson com 800 222 5877 Outside North America 00800 1155 4499 Single Phase UPS Server Cabinets liebert upstech emerson com 800 222 5877 Outside North...

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