Liebert 8 Tons, 50 & 60Hz Replacing the Humidifier Canister, Circuit Board Adjustments, Amps

Page 64

System Operation, Testing, and Maintenance

Replacing the Humidifier Canister

The proper procedure to replace the humidifier canister is:

1.Turn off the humidifier by lowering the humidity setpoint below the ambient humidity level. Record the original setpoint.

2.Turn unit off at wallbox.

3.Place the RUN/DRAIN switch in the DRAIN position to drain the water from the canister.

4.Return the RUN/DRAIN switch to the RUN position after the canister has drained.

5.Turn OFF the power at the main unit.

6.Remove the cover from the humidifier cabinet.

7.Locate the power wires to the steam canister. They are connected to the canister with 1/4" quick connects. Make note of the wiring configuration before removing any wires. Refer to schematic on unit. Slide the rubber boot back to expose the connections. Remove the three (3) power wires and the canister full wire. Do not loosen the screws that secure the electrodes.

! WARNING

Canister and steam hose may be hot! Allow time for the humidifier to cool before replacing parts.

8.Loosen the steam outlet hose clamps and slide the steam hose away from the canister fitting.

9.Remove the canister.

10.Reverse Previous steps to re-assemble humidifier, paying special attention to the following:

! WARNING

Hazardous voltage! use extreme caution. Circuit board adjustment should be performed by qualified personnel only.

Power should be disconnected prior to the procedure.

6.2.7Circuit 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 setpoint. Raising the value increases the frequency of drain cycles.

Lowering the value decreases the frequency of drain cycles.

The frequency should be increased for highly conductive water and decreased for less conductive water. If adjustment is necessary, and a change of three to four percent in either direction does not permit normal operation of the unit, consult your Liebert supplier.

The POT1 controls the duration of the drain cycle. This adjustment is factory set at 60 seconds (1 VDC) and should not be readjusted without consulting your Liebert supplier.

The DIP switch settings are used to set the capacity of the humidifier. If the humidifier is replaced in the field the DIP switches should be set to the required settings described below.

Table 17 Humidifier control board DIP switch settings

Voltage

SW1

SW2

SW3

SW4

Amps

 

 

 

 

 

 

208

On

On

On

Off

8.9

 

 

 

 

 

 

240

Off

On

On

Off

8.5

 

 

 

 

 

 

380/415

Off

Off

Off

Off

5.2

 

 

 

 

 

 

460

On

On

On

Off

4.5

 

 

 

 

 

 

575

On

On

Off

Off

3.4

 

 

 

 

 

 

56

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Contents Liebert Mini-Mate2 Page Table of Contents Microprocessor Control System Performance Microprocessor ControlsAlarms System OPERATION, TESTING, and MaintenanceFigures Table iii Heat rejection matchup 60 Hz Table iv Heat rejection matchup 50 HzPage Standard Product Features Optional Equipment Ancillary Ship Loose Accessories Installation Considerations Input Voltage Entering Fluid Temperature MinRoom Preparation Application limits, evaporator and chilled-water unitsLocation Considerations Drycooler Evaporator Unit weights System WeightsEquipment Inspection upon receipt Nylock Installing the Evaporator or Chilled-Water UnitsLocking nut Hex nut Close Coupled Installations Nut Clamps are for shipping purposes onlyEvaporator Air Distribution Filter Box Connections for Ducted SystemsEvaporator external static pressure 60 at 3750 CFM 6371 CMH Hp Motor std Hp Motor opt Turns External OpenDrain installation Piping Connections and Coolant Requirements Drain LineCondensate Pump Humidifier Water Supply LineGeneral arrangement diagram chilled-water systems Chilled-Water Piping-Chilled-water Systems OnlyRecommended refrigerant line sizes Refrigerant R-22 PipingEquivalent Suction Feet Circuit Liquid Line Total refrigerant = Units and Lines Quick Connect FittingsTon unit refrigerant charge Line charges field pipingOptional Filter BOX Power Connections Electrical Connections, Evaporator or Chilled-Water UnitEvaporator unit electrical connections Front of UnitGeneral Considerations DuctingConsiderations for Specific Applications Electrical Connections Condensing Unit Piping ConnectionsControl Connections DPN000248Rev1 Heat rejection connection. Field Outdoor Air-Cooled Condensing Unit Installation Electrical ConnectionsElectric service connection High voltageLow voltage Earth ground connectionFootprint Dimensions 152 11-1/2292 Condensing Unit Fluid Requirements Water/Glycol Piping ConsiderationsRegulating Valve Indoor water/glycol condensing unit dimensional data Site Preparation and Installation Two circuits provided. Single circuit shown Optional Equipment Piping Optional free cooling coil 3-way valve on water/glycol unitsOptional free cooling coil 3-way valve on air-cooled units Checklist for Completed Installation Feature Overview Wall boxMain Menu Menu Active Alarms Alarm HistoryDefault setpoints and allowable ranges SetpointsSetup Operation Restart Time DelayTime DateShow DIP Switch 10.2 C/F DegreesHumidity Control Method Lead CompressorChange Passwords Alarm EnableSetup functions, default values and allowable ranges Calibrate SensorsAlarm Time Delay Common Alarm EnableCustom Alarms Alarm default time delaysEquipment Options Switches Custom TextLCD Display Contrast Nonvolatile MemoryTest Outputs Run DiagnosticsTest Inputs Test Micro TB3-1 TB3-2 TB3-3 TB4-4 Wall Box DIP Switches TB3-4 Connection to Terminal #4 WallboxTB3-3 Connection to Terminal #3 Wallbox TB3-2 Connection to Terminal #2 WallboxCooling Control Type Response Proportional ControlReheat Load Control Features Dehumidification / Humidification Percent RequiredCommunications Humidification Operation System ActivationAlarms Definitions and Troubleshooting Custom AlarmsHigh Head Pressure Air-Cooled SystemsTemperature Humidifier Problem AlarmHigh-Water Alarm Loss of PowerOptional/Custom Alarms Change FilterSystem Testing Maintenance and Component Operation Refrigeration System Suction PressureDischarge Pressure Thermostatic Expansion ValveRegulating Valves Water/Glycol Condensing Units Glycol Solution MaintenanceHot Gas Bypass Optional Replacement Procedures Steam Generating Humidifier Operation Procedures Circuit Board Adjustments Humidifier control board DIP switch settingsReplacing the Humidifier Canister AmpsMaintenance Inspection Checklist Troubleshooting Symptom Possible Cause Check or Remedy Cooling cycle too ShortDisplay freezes Control padsTroubleshooting Troubleshooting Troubleshooting Page Net ItiTin That