Precision Cooling For Business-Critical Continuity™ Liebert Mini-Mate2™ Operation & Maintenance Manual - 5 Tons, 50 & 60Hz
TABLE OF CONTENTS PRODUCT MODEL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V 1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 1.1 Product Description and Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 1.1.2 1.1.3 1.2 Optional Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.7 Indoor Water and Glycol Cooled Condensing Unit Installation . . . . . . . . . . . . . . . . . . . . . . 19 2.7.1 2.7.2 2.7.3 2.8 Location Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Piping Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.0 ALARMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5.1 Alarms: Definitions and Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5.1.1 5.1.2 5.1.3 5.1.4 5.1.5 5.1.6 5.1.7 5.1.8 5.2 Custom Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . High Head Pressure . . . . . . . . . . . . . . . . .
FIGURES Figure i Figure ii Figure iii Figure iv Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Model number designation—Evaporators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v Model number designation—chilled water units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PRODUCT MODEL INFORMATION Figure i Model number designation—Evaporators M = Mini-Mate2 M = Microprocessor Control D = Disconnect Switch 0 = No Disconnect Switch Nominal BTUHs (1000) E = Split Evaporator K = Evaporator w/Free Cooling (3-way) M M D 60 E - C H E L A - = DX Evaporator A = 460V-3ph-60hz B = 575V-3ph-60hz C = 208V-3ph-60hz D=230V-3ph-60hz M=380/415V-3ph-50hz H = Canister Humidifier 0 = No Humidifier 0 = No Reheat E = Electric Reheat S = SCR Reheat H = Hot Water Reheat L = Low Speed
Figure ii Model number designation—chilled water units M = Mini-Mate2 M = Microprocessor Control D = Disconnect Switch 0 = No Disconnect Switch Nominal BTUHs (1000) C = Chilled Water M M D 92 C 2 C H E L A 2 = 2-Way Chilled Water Slow-Close Valve 3= 3-Way Chilled Water Slow-Close Valve D = 2-Way Mod Chilled Water Valve T = 3-Way Mod Chilled Water Valve A = 460V-3ph-60hz B = 575V-3ph-60hz C = 208V-3ph-60hz D=230V-3ph-60hz M=380/415V-3ph-50hz H = Canister Humidifier 0 = No Humidifier 0 = No Rehe
Figure iii Model number designation—air cooled centrifugal condensing units M = Mini-Mate2 C = Condensing Unit D = Disconnect Switch 0 = No Disconnect Switch Nominal BTUHs (1000) M C D 65 A L A H A = Air Cooled Unit L = 95°F Ambient Lee-Temp (Air) A = 460V-3ph-60Hz B = 575V-3ph-60Hz Y = 208/230V-3ph-60Hz M = 308/415V-3ph-50Hz H = Hot Gas Bypass 0 = No Hot Gas Bypass 0 = Revision Level vii 0
Figure iv Model number designation—water/glycol condensing units M = Mini-Mate2 C = Condensing Unit D = Disconnect Switch 0 = No Disconnect Switch Nominal BTUHs (1000) M C D 69 W 2 A H A = Air Cooled Unit 2 = 2-Way Chilled Water Slow-Close Valve 3= 3-Way Chilled Water Slow-Close Valve D = 2-Way Mod Chilled Water Valve T = 3-Way Mod Chilled Water Valve A = 460V-3ph-60hz B = 575V-3ph-60hz Y = 208/230V-3ph-60hz M = 308/415V-3ph-50hz H = Hot Gas Bypass 0 = No Hot Gas Bypass 0 = Revision Level Tabl
Introduction 1.0 INTRODUCTION 1.1 Product Description and Features The Mini-Mate2™ is a temperature/humidity control system designed to be installed above a ceiling grid system. The unit is available as a split system evaporator to be matched with an Indoor Centrifugal Condensing Unit, Outdoor Prop Fan Condensing Unit or Indoor Water/Glycol Condensing Unit. A self-contained Chilled Water Fan Coil is also available. 1.1.
Introduction 1.2.3 SCR Electric Reheat The optional electric reheat is pulsed rapidly to provide precise temperature control, while cooling is locked on. A safety switch prevents the reheat from exceeding temperature limits. 1.2.4 Hot Water Reheat The optional hot water reheat circulates building hot water through a cleanable Y-strainer, solenoid valve and finned-tubed heating coil to provide reheat. 1.2.
Site Preparation and Installation 2.0 SITE PREPARATION AND INSTALLATION NOTE Before installing unit, determine whether any building alterations are required to run piping, wiring and duct work. Carefully follow all unit dimensional drawings and refer to the submittal engineering dimensional drawings of individual units for proper clearances. 2.1 Installation Considerations The evaporator unit is usually mounted above the suspended ceiling in the space to be conditioned.
Site Preparation and Installation 2.1.2 Location Considerations CAUTION ! Units contain water. Water leaks can cause damage to sensitive equipment below. DO NOT MOUNT UNITS OVER SENSITIVE EQUIPMENT. A field supplied pan with drain must be installed beneath cooling units and water/glycol cooled condensing unit. NOTE Do NOT mount units in areas where normal unit operating sound may disturb the working environment. Locate the evaporator unit over an unobstructed floor space if possible.
Site Preparation and Installation Figure 3 Chilled water systems Evaporator Chilled Water Fan Coil Supply & Return Air Ducted Remote Chilled Water Source 2.2 System Weights Table 4 Unit weights Cooling Units* lbs kg. MMD60E 498 226 MMD59E 498 226 Condensing Units lbs. kg. MCD65A 449 204 MCD64A 449 204 MCD69W 282 128 MCD68W 282 128 *Add 40 lbs. (20 kg.) to units with free cooling or hot water reheat coils. 2.
Site Preparation and Installation 2.4 Installing the Ceiling Units ! WARNING Be sure the supporting roof structure is capable of supporting the weight of the unit(s) and the accessories during installation and service. (See 2.2 - System Weights.) Be sure to securely anchor the top ends of the suspension rods. make sure all nuts are tight. The evaporator unit and indoor condensing unit are usually mounted above the ceiling and must be securely mounted to the roof structure.
Site Preparation and Installation If the return air duct is short or if noise is likely to be a problem, sound-absorbing insulation should be used inside the duct. Duct work should be fabricated and installed in accordance with local and national codes. Table 5 Evaporator external static pressure 1.5 hp Motor (60hz) 2.0 hp Motor (60hz) Turns Open Blower rpm External Static, in. Blower rpm External Static, in. 1 n/a n/a 1329 n/a 1.5 n/a n/a 1296 n/a 2 1037 0.9 1264 n/a 2.5 1005 0.
Site Preparation and Installation Water/Glycol Piping—Water and Glycol cooled systems require coolant loop connections as specified in the condensing unit installation instructions. Refrigerant (R-22) Piping—All split systems require two refrigerant lines (an insulated copper suction line and a copper liquid line) between the evaporator and the condensing unit. Two possible methods exist for installing the copper suction and liquid lines. • Close coupling the units together using the quick connects.
Site Preparation and Installation Quick Connect Fittings NOTE When hard piping is used, complete all piping and evacuate lines before connecting quick connects. Be especially careful when connecting the quick connect fittings. Read through the following steps before making the connections. 1. 2. 3. 4. 5. Remove protector caps and plugs. Carefully wipe coupling seats and threaded surfaces with a clean cloth. Lubricate the male diaphragm and synthetic rubber seal with refrigerant oil.
Site Preparation and Installation Figure 4 Evaporator unit dimensional data 46 1/2 " (1181.1mm) CABINET DIMENSION Air Outlet Air Inlet 24 " (610mm) CABINET DIMENSION 7 5/8 " (193.5mm) 3 1/8 " (79.4mm) 13 3/8 " (339.7mm) 14 1/2 " (368.3mm) Removable Access Panels 3/8" (10mm) Holes for Module Rigging (typ. 2 each end) 22 7/16 " (570mm) 13/16 " (20.6mm) 1 1/8 " (28.6mm) 36 7/8 " (936.6mm) Customer Supplied Threaded Rods for Module Support from Ceiling (typ. 4) 49 " (1244.
Site Preparation and Installation Figure 5 Threaded rod and hardware kit installation 3/8" Threaded Rod (field-supplied) 3/8" Hex Nut 3/8" Washer Sleeve Isolator 3/8" Fender Washer 3/8" Hex Nut 3/8" Hex Nut Nylock Unit Base Pan (ref) 11
Site Preparation and Installation 2.4.4 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. ! ! WARNING Unit contains hazardous electrical voltage. disconnect power supply before working within. line side of factory disconnect remains energized when disconnect is off.
Site Preparation and Installation Figure 6 Evaporator unit electrical connections Earth Ground Connection Connection terminal for field supplied earth grounding wire. High Volt Power Connections Electric service connection terminals. Optional factory installed disconnect switch. Remote Humidifier Contact Field Supplied 24V Class 2 wiring to terminals 11 & 12 in field wire compartment Optional Condensate Pump Auxilary Float Switch Connection to terminal TB1-8 and TB1-9. Heat Rejection Connection.
Site Preparation and Installation Figure 7 Close coupled installation Evaporator Unit (Left) Condensing Unit (Right) Evaporator Unit Spacer Between Close-Coupled Evaporator and Condensing Unit (4 places) Condensing Unit Refrigerant Quick Connect Fittings (Inside Units) 14
Site Preparation and Installation 2.5 Indoor Air Cooled Centrifugal Fan Condensing Unit Installation 2.5.1 Location Considerations The centrifugal fan air cooled condensing unit may be located above the dropped ceiling or any remote indoor area. If noise is of concern, the condensing unit should be located away from personnel. Normal operating sound may be objectionable if the condensing unit is placed near quiet work areas. To mount the unit in the ceiling, refer to 2.4 - Installing the Ceiling Units.
Site Preparation and Installation Figure 8 Indoor air cooled centrifugal condensing unit dimensions and pipe connections 54 " (1371.6mm) CABINET DIMENSION 32 " (812.8mm) CABINET DIMENSION 1 5/8 " (41.1mm) 15 3/4 " (400mm) 8 15/16 " (227mm) 48 " (1219.2mm) Customer supplied threaded rods for module support from ceiling (typ. 4) 3 3/8 " (85.7mm) 14 1/2 " (368.3mm) 21 1/4 " (539.
Site Preparation and Installation Figure 9 Indoor air cooled centrifugal condenser electrical connections Field Supplied Unit Disconnect Switch when Factory Unit Disconnect Switch is not Supplied Electric Service not by Liebert Optional Factory Installed Disconnect Switch Connection Terminal for Field Supplied Earth Grounding Wire Line Voltage Electric Power Supply Conduit Voltage Removable Access Panels Field Supplied 24V NEC Class 2 Wiring Between Condensing Unit and Fan/Coil Unit Low VoltageElec
Site Preparation and Installation Figure 10 System piping with indoor or outdoor air cooled condensing unit Condenser Coil High Pressure Switch Scroll Compressor Liquid Injection Valve Bulb Hot Gas Bypass Solenoid Valve Suction Line Male Quick Connect Coupling * Suction Line Female Quick Connect Coupling 1/2" (12.
Site Preparation and Installation 2.6.2 Piping Connections Details for Refrigerant (R-22) Loop piping are in 2.4.3 - Piping Connections and Coolant Requirements. 2.6.3 Electrical Connections Refer 2.4.4 - Electrical Connections for general wiring requirements and cautions. Refer to electrical schematic when making connections. Power Connections The outdoor condensing unit requires its own power source and earth ground, with a disconnect switch (field supplied) to isolate the unit for maintenance.
Site Preparation and Installation 2.7.3 Piping Connections Details for Refrigerant (R-22) Loop piping are in 2.4.3 - Piping Connections and Coolant Requirements. Water/Glycol Piping Considerations Manual service shut-off valves must be installed at the supply and return line to each unit. This enables routine service and/or emergency isolation of the unit. When the condensing unit fluid quality is poor, filters that can be easily serviced should be placed in the supply line.
Site Preparation and Installation Figure 11 Indoor water/glycol condensing unit dimensional data 32 " (812.8mm) CABINET DIMENSION 32 " (812.8mm) CABINET DIMENSION Customer supplied threaded rods for module support from ceiling (typ. 4) Removable Access Panel 1/2" (12.7mm) dia. holes for module rigging (typ. 2 each end) 24 " (610mm) CABINET DIMENSION Hanger Bracket Shaded area indicates a recommended clearance of 30" (762mm) for component access and removal 33 5/8 " (854.
Site Preparation and Installation Figure 12 Indoor water/glycol condensing unit electrical field connections Field Supplied Unit Disconnect Switch when Factory Unit Disconnect Switch is not Supplied. Electric Service not by Liebert Optional Factory Installed Disconnect Switch Field Supplied 24V NEC Class 1 Wiring to Fan/Coil Unit. Field Supplied 24V NEC Class 1 Wiring to Drycooler (Glycol cooled units only). Line VoltageElectric Power Supply Conduit Voltage.
Site Preparation and Installation Figure 13 System piping with indoor water/glycol cooled condensing unit Tube in Tube Condenser Scroll Compressor High Pressure Switch Liquid Injection Valve Bulb Hot Gas Bypass Solenoid Valve Suction Line Male Quick Connect Coupling Suction Line Female Quick Connect Coupling External Equalizer Sensing Bulb Fluid Return From Unit Liquid Injection Valve Expansion Valve Liquid Line Female Quick Connect Coupling Water/Glycol Supply Line Fluid Supply To Unit Servi
Site Preparation and Installation 2.8 Optional Equipment Piping 2.8.1 Free-Cooling Coil The free-cooling coil is a secondary coil located downstream of the DX coil. The free-coiling coil does not operate at the same time as the DX coil. A temperature sensor is factory-mounted to the free-cooling piping. If the water temperature is less than the set temperature (usually 45°F [7.2°C]), the 3-way valve opens to allow chilled water flow to the free-cooling coil and the compressor is locked off.
Site Preparation and Installation 2.8.2 Hot Water Reheat Coil Building hot water can be piped to a factory-installed hot water reheat coil, located downstream of the cooling coil. A factory-installed solenoid valve opens upon a call for reheat.
Site Preparation and Installation 2.9 Checklist for Completed Installation ___ 1. Proper clearance for service access has been maintained around the equipment. ___ 2. Equipment is level and mounting fasteners are tight. ___ 3. Piping completed to refrigerant or coolant loop (if required). Refrigerant charge added (if required). ___ 4. Condensate pump installed (if required). ___ 5. Drain line Connected. ___ 6. Water supply line connected to humidifier (if required). Route to allow air filter removal.
Microprocessor Control 3.0 MICROPROCESSOR CONTROL The Microprocessor Control for the Liebert Mini-Mate2 unit features an easy to use menu-driven LCD display. The menus, control features and circuit board details are described in this section. Detailed information concerning controls (4.0 - System Performance Microprocessor Controls) and alarms (5.0 - Alarms) are provided. 3.1 Feature Overview To turn the unit ON, press the ON/OFF (I/O) key after power is applied.
Microprocessor Control 3.2 Main Menu
Microprocessor Control Table 11 Default setpoints and allowable ranges Setpoint 3.4 Default Range Temperature Setpoint 72°F 40-90°F (5-32°C) Temperature Sensitivity 2.0°F 1-9.9°F (0.6-5.
Microprocessor Control 3.8 Setback The microprocessor can be programmed for night and weekend setback. Two (2) events can be programmed for a five-day work week and two (2) events can be programmed for a two-day weekend. The following table can be used to devise a setback plan. Table 12 Night and weekend setback plan Event Weekend Weekday Time 1 Temperature1 Sensitivity 1 Humidity 1 Humidity Sensitivity 1 Time 2 Temperature 2 Sensitivity 2 Humidity 2 Humidity Sensitivity 2 3.
Microprocessor Control 3.9.3 Humidity Control Method The operator may select either relative (direct) or absolute (predictive) humidity control. If “relative” is selected, the RH control is taken directly from the RH sensor. If “absolute” is selected, the RH control is automatically adjusted whenever return air temperature deviates from the desired temperature setpoint (i.e., predictive humidity control). The LCD display will indicate percentage relative humidity for both methods of control.
Microprocessor Control 3.10 Change Passwords The display will prompt the operator to enter a three digit password when attempting to make changes. The system includes two (2) passwords, one for setpoints and one for setup. The system allows the password to be changed by first entering the default password set at the factory (1-2-3) for setpoints and (3-2-1) for setup. The password function provides system security so that only authorized personnel are allowed to make changes to the system.
Microprocessor Control 3.14 Common Alarm Enable Each individual alarm can be selected to activate or deactivate the common alarm relay. If the energize common alarm function is set to Yes, the relay is energized immediately as the alarm is annunciated and de-energized when the alarm condition has been recognized. If the alarm is completely Disabled, the alarm has no effect on the common alarm relay.
Microprocessor Control Equipment Options Switches Equipment options are selected and enabled using DIP switches 1 through 7. These are located on the control board near TB1. These switches are factory-set and should not require any user changes. The setting and function of the switches can be individually read on the LCD display. NOTE In order to update the dip switch settings, power must be cycled off, then on, from the unit disconnect switch.
Microprocessor Control Test Outputs When this feature is selected, the controller is effectively turned off. When stepping from one load to the next, the previous load is automatically turned off. The loads can also be toggled On and 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.
Microprocessor Control Figure 17 Control menu Setpoints/Setup Temp Setpt Temp Sens Hum Setpt Hum Sens Hi Temp Alm Lo Temp Alrm Hi Hum Alm Lo Hum Alm Status Heat % Dx Cool % Dehumidify % Humidify % Status Display 75 F 50%RH NO ALARMS Setup Password Enter New PSW Setup PSW = 000 Calibrate sensors Temp Cal Hum Cal Temp Delay Hum Delay 0 0 0 0 Active Alarms No Alarms or Alarm 01 of 01 High Head Menu Setpoints Status Active Alarms Time Date Setback Setup Operation Setpoint Password Setup Password Calibrate
Microprocessor Control Figure 18 Control board—inside evaporator TB2-4 — Hot Gas Bypass TB2-3 — High Head Alarm Connection TB2-2 — Heat Rejection TB2-1 — Heat Rejection TB1-9 — Condensate Pump Aux Alarm TB1-8 — Condensate Pump Aux Alarm TB1-7 — Common Alarm Connection TB1-6 — Common Alarm Connection TB1-5 — Remote Shutdown TB1-4 — Remote Shutdown TB1-3 — Customer Alarm Connection #2 TB1-2 — Customer Alarm Connection #1 TB1-1 — Customer Alarm Connection (common) TB3-4 TB3-3 TB3-2 TB3-1 Connection to TB3 P
System Performance Microprocessor Controls 4.0 SYSTEM PERFORMANCE MICROPROCESSOR CONTROLS This section describes in detail how the Mini-Mate2 responds to operator inputs and room conditions. 4.1 Temperature Control 4.1.1 Cooling/Heating Required The temperature control program for the microprocessor is based on a calculated percentage requirement for cooling/heating. 4.1.
System Performance Microprocessor Controls 4.2.3 Humidification Operation The canister humidifier is activated when the humidity control calculates a requirement of 100% humidification; and is deactivated when the humidification requirement falls below 50%. 4.3 Load Control Features The control system monitors the compressor and prevents it from turning on within a 3 minute period of being off. If this on-off-on cycle occurs too often (e.g., 10 times in one hour) a Short Cycle Alarm will occur. 4.3.
Alarms 5.0 ALARMS The microprocessor control system will audibly and visually signal all ENABLED Alarms (including two (2) custom alarms). These special alarms can be chosen from the optional alarm list and/or can have their own fully custom text. The custom alarm inputs are contact closures wired from terminal TB1-1 through a normally open contact to either TB1-2 (alarm 1) or TB1-3 (alarm 2). The alarms can be enabled or disabled (refer to 3.
Alarms 5.1.3 Humidity Level The humidity level alarm may be activated under the following conditions: • High: The room return air humidity exceeds the pre-set high humidity alarm set point. Is the unit set up for dehumidification? Check DIP switch. • Low: The room return air humidity decreases to the low humidity alarm set point. Is the unit setup for humidification? Check DIP switch.
Alarms 5.2 Optional/Custom Alarms 5.2.1 Change Filter Periodically, the return air filters in the evaporator must be changed. The Change Filter alarm notifies the user that filter replacement 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. 5.2.2 Firestat The optional firestat feature is a bi-metal operated sensing device with a closed switch under normal conditions.
System Operation, Testing and Maintenance 6.0 SYSTEM OPERATION, TESTING AND MAINTENANCE This section describes system testing, maintenance and replacement procedures. Use copies of the Maintenance Inspection Checklist to record preventive maintenance inspections. ! WARNING Unit contains hazardous electrical voltage. Disconnect power supply before working within. Line side of factory disconnect remains energized when disconnect is off. 6.1 System Testing 6.1.
System Operation, Testing and Maintenance 6.2.3 Blower System Monthly inspection of the blower package include: motor mounts, belts, fan bearings and impellers. Fan impellers should be thoroughly inspected and any debris removed. Check to see if they are tightly mounted on the fan shaft and do not rub against the fan housing during rotation. Motor bearings are permanently sealed and self-lubricating and do NOT need lubricated. The drive belt should be checked monthly for signs of wear and proper tension.
System Operation, Testing and Maintenance Discharge Pressure The discharge pressure will vary greatly with load and ambient conditions (Table 18). The high-pressure switch will shut the compressor down at its cut-out setting. Table 18 Typical discharge pressures System Design psig (kPa) Air Cooled 180-275 (1242-1895) Water Cooled 65ºF to 85ºF water (18 to 29.
System Operation, Testing and Maintenance Hot Gas Bypass (Optional) Operation The hot gas bypass valve is installed between the compressor discharge piping and suction piping, bypassing the condenser and evaporator coils. The discharge gas mixes with the suction gas, raising the suction temperature and pressure and decreasing the mass flow through the evaporator.
System Operation, Testing and Maintenance Replacement Procedures Compressor Replacement—Infrequently a fault in the motor insulation may result in a motor burnout (if system is properly installed, motor burnout rarely occurs). Primarily this type of failure is due to mechanical or lubrication problems, where the burnout is a secondary consequence. Early detection can prevent a large percentage of the problems that can cause compressor failures.
System Operation, Testing and Maintenance Proper procedures to remove and replace the failed compressor are: 1. Disconnect power 2. Attach suction and discharge gauges to access fittings. 3. Recover refrigerant using standard recovery procedures and equipment. NOTE Release of refrigerant to the atmosphere is harmful to the environment and unlawful. Refrigerant must be recycled or discarded in accordance with federal, state and local regulations. 4. Remove failed compressor. 5.
System Operation, Testing and Maintenance 5. Over a period of time, the electrode surface will become coated with a layer of insulating material, which causes a drop in current flow. As this happens, the water level in the canister will slowly rise exposing new electrode surface to the water to maintain normal output. Eventually, the steady state water level will reach the canister full electrode and indicate so by activating the canister full alarm.
System Operation, Testing and Maintenance 6.2.7 Circuit Board Adjustments The humidifier control board governs humidifier operation. There are three potentiometers mounted on the board and can be used to adjust for extreme water conductivity conditions. POT2 controls the amperage at which the drain will energize and is clearly marked in percentages. This adjustment is factory-set at 85%, which indicates that the unit will drain when the amperage falls off to 85% of the capacity set point.
Maintenance Inspection Checklist 7.0 MAINTENANCE INSPECTION CHECKLIST Liebert Mini-Mate2 Date:____________________________________ Prepared By:____________________________________ Model #:_________________________________ Serial Number:__________________________________ NOTE Reheat element sheaths and fins are manufactured with stainless steel. Regular inspections are necessary to assure proper cleanliness of the reheating element.
Troubleshooting 8.0 TROUBLESHOOTING Table 20 Troubleshooting Symptom Unit will not start Possible Cause No power to unit Check voltage at input terminal block. Control voltage circuit breaker (at transformer) open Locate short and reset circuit breaker. Float switch relay closed because of high water in the condensate pan Has rubber band been removed from float switch? Check drain and line. Access through left panel. Power must be cycled at the disconnect to reset.
Troubleshooting Table 20 Troubleshooting Symptom Possible Cause Cooling cycle too short Sensor response delay too short Display freezes and control pads do not respond Static discharge Condensate pump does not operate Open or short circuit in wiring Increase sensor response delay. See 3.11 - Calibrate Sensors. During period of low humidity, static electricity can cause the control program to freeze or display incorrect information.
Troubleshooting NOTES 54
Troubleshooting 55
Troubleshooting 56
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