Manitowoc Ice S1800 service manual Analyzing Suction Pressure During Freeze Cycle

Page 79

Section 7	Refrigeration System

ANALYZING SUCTION PRESSURE

DURING FREEZE CYCLE

The suction pressure gradually drops throughout the freeze cycle. The actual suction pressure (and drop rate) changes as the air and water temperatures entering the ice machine change. This affects freeze cycle times.

To analyze and identify the proper suction pressure drop throughout the freeze cycle, compare the published suction pressure to the published freeze cycle time. “Operating Pressure” and “Freeze Cycle Time” charts can be found later in this section.

Procedure

NOTE: Analyze discharge pressure before analyzing suction pressure. High or low discharge pressure may be causing high or low suction pressure.

Step

Example Using SY1004A Model Ice Machine

1. Determine the ice machine operating

Air temp. entering condenser:

90°F/32.2°C

Air temp. around ice machine:

80°F/26.7°C

conditions.

Water temp. entering water fill valve:

70°F/21.1°C

2A. Refer to “Cycle Time” and “Operating

Pressure” charts for ice machine model being

Published freeze cycle time:

Published freeze cycle suction pressure:

checked. Using operating conditions from Step

8.5 - 9.8 minutes

58-28 PSIG

1, determine published freeze cycle time and

published freeze cycle suction pressure.

Published Freeze Cycle Time (minutes)

2B. Compare the published freeze cycle time

1

3

5

8

10

and published freeze cycle suction pressure.

Develop a chart.

58

52

43

33

28

Published Freeze Cycle Suction Pressure (psig)

3. Perform an actual suction pressure check at

Beginning of freeze cycle:

70 PSIG at

1 minute

the beginning, middle and end of the freeze

Middle of freeze cycle:

57 PSIG at

7 minutes

cycle. Note the times at which the readings are

End of freeze cycle:

40 PSIG at 14 minutes

taken.

4. Compare the actual freeze cycle suction

Time Into

Published

Actual

Result

Freeze Cycle

Pressure

Pressure

pressure (Step 3) to the published freeze cycle

1 minutes

58 PSIG

70 PSIG

High

time and pressure comparison (Step 2B).

Determine if the suction pressure is high, low

5 minutes

43 PSIG

48 PSIG

High

or acceptable.

10 minutes

28 PSIG

40 PSIG

High

Part Number 80-1634-3

7-13

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Contents Service Manual Personal Injury Potential Read These Before ProceedingTable of Contents Section Maintenance Table of Contents Section Ice Machine OperationSection Before Calling For Service Section Refrigeration System Table of Contents Section Electrical SystemTable of Contents Self-Contained Water-Cooled How to Read a Model NumberModel Numbers Ice Cube SizesGeneral Information Section Accessories Model/Serial Number Location Section General Information Model/Serial Number LocationWarranty Coverage General Ice Machine DimensionsWidth, Depth, and Height Dimensions Electrical and AuCS DimensionsSeries Heat of Rejection Ice Machine Air Conditioning Installation Instructions Section Location of Ice MachineIce Machine Heat of Rejection S1800M Water-CooledElectrical Requirements Section Installation Instructions Electrical ServiceVoltage Minimum Circuit AmpacitySelf Contained ICE Machine 230/1/50 For United Kingdom OnlySelf Contained ICE Machine 115/1/60 or 208-230/1/60 Self Contained ICE Machine 208-230/3/60Drain Connections Cooling Tower ApplicationsWater Supply Water Inlet LinesCondenser Installation Instructions SectionTypical Water Supply Drain Installation Water Supply and Drain Line SIZING/CONNECTIONSSection Installation Instructions Installation Check List Potential Personal Injury Situation AuCS Automatic Cleaning SystemComponent Identification Section Ice Machine OperationInitial START-UP or START-UP After Automatic SHUT-OFF Ice Machine Operation Section Sequence Of OperationAutomatic SHUT-OFF 7. Automatic Shut-Off Safety TimersHarvest Sequence 5. Water Purge HarvestIce Thickness Check Ice Machine Operation Section Operational ChecksWater Level ICE Thickness CheckHarvest Sequence Water Purge Water Purge AdjustmentThis page Intentionally Left Blank Ice Machine Operation SectionAlphaSan→ Exterior CleaningIce Machine Inspection Water-Cooled Condenser Water Regulating ValveSachet Replacement Procedure Maintenance Section GuardianInstallation Sachet Replacement FrequencyStep Section Maintenance Interior Cleaning and SanitizingCleaning Procedure Model Amount of CleanerSanitizing Procedure Maintenance SectionSolution Type Water Mixed With Sanitizer Solution Type Water Mixed With Removal of Parts for CLEANING/SANITIZINGWater Curtain Removal Ice Thickness Probe Water CurtainIce Thickness Probe Removal Water Trough Water Distribution TubeWater Distribution Tube Removal Water Pump Water Level ProbeWater Pump Removal Water Dump Valve Dump Valve DisassemblyDrain Line Check Valve Evaporator Tray RemovalWater Inlet Valve Pry Open the Water Regulating Valve AUCS→ Accessory Maintenance Section Removal from Service/WinterizationSELF-CONTAINED WATER-COOLED ICE Machines Problem Possible Cause To Correct ChecklistSafety Limit Feature Before Calling For Service SectionSection Electrical System Energized Parts ChartsSELF-CONTAINED WATER-COOLED Models Self-Contained Water Purge SELF-CONTAINED ModelsInitial Start-Up or Start-Up After Automatic Shut-Off Water PurgeRefrigeration System START-UP Refrigeration System Start Up 5 Seconds Toggle SwitchSelf-Contained Refrigeration System Start-Up Self-Contained Pre-Chill Self-Contained Models Electrical System SectionFreeze Sequence PRE-CHILLFreeze Toggle Switch Bin Switch Control Board RelaysSelf-Contained Freeze Self-Contained Models Harvest Sequence Harvest Automatic SHUT-OFF Automatic Shut-OffSelf-Contained Automatic Shut-Off Wiring Diagram Legend Section Electrical System Wiring DiagramsControl Board S1800 SELF-CONTAINED 1 PhaseS1800 SELF-CONTAINED 3 Phase Main Fuse SpecificationsCheck Procedure BIN SwitchWater Curtain Removal Notes SymptomsDiagnostic Aids Continuity TestDetermine if the Compressor is Seized Compressor Electrical DiagnosticsCheck Resistance Ohm Values Check Motor Windings to GroundWhat is a PTCR? Ptcr DiagnosticsCompressor Start Sequence During Start-Up First .25 1.0 Seconds Troubleshooting PTCR’sWHY a Good Ptcr MAY Fail To Start the Compressor Model Automatic Shut-Off and RestartPart Number Checking the PtcrManitowoc Ptcr Model Manitowoc Cera-Mite RoomRelay Operation Check Diagnosing Start ComponentsCapacitor RelaySwitch Setting Terminals Ohm Reading ICE/OFF/CLEAN Toggle SwitchControl Board Electronic Control BoardInputs Safety LimitsHarvest Light Freeze Time LOCK-IN FeatureIce Thickness Probe Cleaning HOW the Probe WorksMonitoring of Harvest Light Correction Diagnosing ICE Thickness Control CircuitryFreeze Cycle Circuitry Water Inlet Valve Safety SHUT-OFFElectrical System Section Water Level Control Circuitry Water Level Probe LightDiagnosing Water Level Control Circuitry Problem Water Trough Overfilling During Freeze CycleWait until the freeze cycle starts On or OFF Step Check Self Contained 1 Phase with Terminal Board Freeze Cycle Refrigeration Sequence SELF-CONTAINED Water -COOLED ModelsRefrigeration System Section S1800 SELF-CONTAINED Tubing Schematic General Times are in minutes Before Beginning ServiceWeights are in pounds ICE Production CheckWater System Checklist INSTALLATION/VISUAL Inspection ChecklistPossible Problem Corrective Action Extremely Thin at Evaporator Outlet ICE Formation PatternNormal Ice Formation No Ice Formation Extremely Thin at Evaporator InletSafety Limit Indication Safety LimitsAnalyzing Why Safety Limits May Stop the Ice Machine Possible Cause Check/Correct Safety Limit NotesSection Refrigeration System Analyzing Discharge Pressure During Freeze or Harvest Cycle ProcedureFreeze Cycle Discharge Pressure High Checklist Freeze Cycle Discharge Pressure Low ChecklistAnalyzing Suction Pressure During Freeze Cycle Step Example Using SY1004A Model Ice MachineFreeze Cycle Suction Pressure Low Checklist Freeze Cycle Suction Pressure High ChecklistHarvest Valve Analysis Harvest Valve Temperature Check GeneralFindings Comments Discharge Line Temperature Analysis General Column 3 TXV Flooding Final AnalysisColumn 1 Harvest Valve Leaking Column 2 LOW CHARGE/TXV StarvingModels Dual Expansion Valve Ice Machine Model Number Refrigeration System Operational Analysis TablesHigh Pressure CUT-OUT Hpco Control Operating Pressures S1800 SeriesSelf-Contained Water-Cooled Cycle Times Hour Ice ProductionConnections SELF-CONTAINED RECOVERY/EVACUATIONCharging Connections Self-Contained Charging ProceduresDetermining Severity Of Contamination System Contamination CLEAN-UPSevere System Contamination Cleanup Procedure Mild System Contamination Cleanup ProcedureSection Refrigeration System 10. Using Pinch-Off Tool Drier End Part Model Connection Size Number FILTER-DRIERSSeries Version Charge S1800M Total System Refrigerant Charges48 oz Recycle RecoverNew Product Specifications Refrigerant DefinitionsReclaimed Refrigerant Recovered or Recycled RefrigerantRefrigerant RE-USE Policy New RefrigerantHFC Refrigerant Questions and Answers This page Intentionally Left Blank Page Attend a Manitowoc Factory Service School