Manitowoc Ice S1800 service manual Harvest Valve Temperature Check General, Harvest Valve Analysis

Page 81

Section 7

Refrigeration System

 

 

HARVEST VALVE TEMPERATURE CHECK General

NOTE: This procedure requires checking both harvest valves.

A harvest valve requires a critical orifice size. This meters the amount of hot gas flowing into the evaporator during the harvest cycle. If the orifice is even slightly too large or too small, long harvest cycles will result.

A too-large orifice causes refrigerant to condense to liquid in the evaporator during the harvest cycle. This liquid will cause compressor damage. A too-small orifice does not allow enough hot gas into the evaporator. This causes low suction pressure, and insufficient heat for a harvest cycle.

Refer to the Parts Manual for proper valve application. If replacement is necessary, Use only “original” Manitowoc replacement parts.

Harvest Valve Analysis

Symptoms of a harvest valve remaining partially open during the freeze cycle can be similar to symptoms of either an expansion valve or compressor problem. The best way to diagnose a harvest valve is by using Manitowoc’s Ice Machine Refrigeration System Operational Analysis Table.

Use the following procedure and table to help determine if a harvest valve is remaining partially open during the freeze cycle.

1.Wait five minutes into the freeze cycle.

2.Feel the inlet of the harvest valve(s).

Important

Feeling the harvest valve outlet or across the harvest valve itself will not work for this comparison.

The harvest valve outlet is on the suction side (cool refrigerant). It may be cool enough to touch even if the valve is leaking.

3. Feel the compressor discharge line.

!Warning

The inlet of the harvest valve and the compressor discharge line could be hot enough to burn your hand. Just touch them momentarily.

4.Compare the temperature of the inlet of the harvest valves to the temperature of the compressor discharge line.

Findings

Comments

The inlet of the

This is normal as the discharge line

harvest valve is cool

should always be too hot to touch and

enough to touch and

the harvest valve inlet, although too

the compressor

hot to touch during harvest, should be

discharge line is hot.

cool enough to touch after 5 minutes

 

into the freeze cycle.

The inlet of the

This is an indication something is

harvest valve is hot

wrong, as the harvest valve inlet did

and approaches the

not cool down during the freeze cycle.

temperature of a hot

If the compressor dome is also entirely

compressor

hot, the problem is not a harvest valve

discharge line.

leaking, but rather something causing

 

the compressor (and the entire ice

 

machine) to get hot.

Both the inlet of the

This is an indication something is

harvest valve and

wrong, causing the compressor

the compressor

discharge line to be cool to the touch.

discharge line are

This is not caused by a harvest valve

cool enough to

leaking.

touch.

 

Part Number 80-1634-3

7-15

Page 80 Page 82
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Page 80 Page 82
Contents Service Manual Personal Injury Potential Read These Before ProceedingTable of Contents Table of Contents Section Ice Machine Operation Section MaintenanceSection Before Calling For Service Section Refrigeration System Table of Contents Section Electrical SystemTable of Contents Model Numbers How to Read a Model NumberIce Cube Sizes Self-Contained Water-CooledGeneral Information Section Accessories Model/Serial Number Location Section General Information Model/Serial Number LocationWarranty Coverage Width, Depth, and Height Dimensions Ice Machine DimensionsElectrical and AuCS Dimensions GeneralIce Machine Heat of Rejection Installation Instructions Section Location of Ice MachineS1800M Water-Cooled Series Heat of Rejection Ice Machine Air ConditioningVoltage Section Installation Instructions Electrical ServiceMinimum Circuit Ampacity Electrical RequirementsSelf Contained ICE Machine 115/1/60 or 208-230/1/60 For United Kingdom OnlySelf Contained ICE Machine 208-230/3/60 Self Contained ICE Machine 230/1/50Water Supply Cooling Tower ApplicationsWater Inlet Lines Drain ConnectionsTypical Water Supply Drain Installation Installation Instructions SectionWater Supply and Drain Line SIZING/CONNECTIONS CondenserSection 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 OperationHarvest Sequence 5. Water Purge Safety TimersHarvest Automatic SHUT-OFF 7. Automatic Shut-OffWater Level Ice Machine Operation Section Operational ChecksICE Thickness Check Ice Thickness CheckHarvest Sequence Water Purge Water Purge AdjustmentThis page Intentionally Left Blank Ice Machine Operation SectionIce Machine Inspection Exterior CleaningWater-Cooled Condenser Water Regulating Valve AlphaSan→Installation Maintenance Section GuardianSachet Replacement Frequency Sachet Replacement ProcedureCleaning Procedure Section Maintenance Interior Cleaning and SanitizingModel Amount of Cleaner StepMaintenance Section Sanitizing ProcedureSolution Type Water Mixed With Sanitizer Solution Type Water Mixed With Removal of Parts for CLEANING/SANITIZINGWater Curtain Water Curtain Removal Ice Thickness ProbeIce Thickness Probe Removal Water Distribution Tube Water TroughWater Distribution Tube Removal Water Level Probe Water PumpWater Pump Removal Water Dump Valve Dump Valve DisassemblyDrain Line Check Valve Evaporator Tray RemovalWater Inlet Valve Maintenance Section Removal from Service/Winterization Pry Open the Water Regulating Valve AUCS→ AccessorySELF-CONTAINED WATER-COOLED ICE Machines Problem Possible Cause To Correct ChecklistSafety Limit Feature Before Calling For Service SectionEnergized Parts Charts Section Electrical SystemSELF-CONTAINED WATER-COOLED Models Initial Start-Up or Start-Up After Automatic Shut-Off SELF-CONTAINED ModelsWater Purge Self-Contained Water PurgeRefrigeration System Start Up 5 Seconds Toggle Switch Refrigeration System START-UPSelf-Contained Refrigeration System Start-Up Freeze Sequence Electrical System SectionPRE-CHILL Self-Contained Pre-Chill Self-Contained ModelsToggle Switch Bin Switch Control Board Relays FreezeSelf-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 Check Procedure SpecificationsBIN Switch Main FuseDiagnostic Aids SymptomsContinuity Test Water Curtain Removal NotesCheck Resistance Ohm Values Compressor Electrical DiagnosticsCheck Motor Windings to Ground Determine if the Compressor is SeizedPtcr Diagnostics What is a PTCR?Compressor Start Sequence WHY a Good Ptcr MAY Fail To Start the Compressor Troubleshooting PTCR’sModel Automatic Shut-Off and Restart During Start-Up First .25 1.0 SecondsManitowoc Ptcr Checking the PtcrModel Manitowoc Cera-Mite Room Part NumberCapacitor Diagnosing Start ComponentsRelay Relay Operation CheckSwitch Setting Terminals Ohm Reading ICE/OFF/CLEAN Toggle SwitchControl Board Electronic Control BoardInputs Safety LimitsIce Thickness Probe Cleaning Freeze Time LOCK-IN FeatureHOW the Probe Works Harvest LightMonitoring of Harvest Light Correction Diagnosing ICE Thickness Control CircuitryElectrical System Section Water Level Control Circuitry Water Inlet Valve Safety SHUT-OFFWater Level Probe Light Freeze Cycle CircuitryProblem Water Trough Overfilling During Freeze Cycle Diagnosing Water Level Control CircuitryWait 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 Weights are in pounds Before Beginning ServiceICE Production Check Times are in minutesINSTALLATION/VISUAL Inspection Checklist Water System ChecklistPossible Problem Corrective Action ICE Formation Pattern Extremely Thin at Evaporator OutletNormal Ice Formation No Ice Formation Extremely Thin at Evaporator InletSafety Limits Safety Limit IndicationAnalyzing Why Safety Limits May Stop the Ice Machine Possible Cause Check/Correct Safety Limit NotesSection Refrigeration System Freeze Cycle Discharge Pressure High Checklist ProcedureFreeze Cycle Discharge Pressure Low Checklist Analyzing Discharge Pressure During Freeze or Harvest CycleAnalyzing Suction Pressure During Freeze Cycle Step Example Using SY1004A Model Ice MachineFreeze Cycle Suction Pressure Low Checklist Freeze Cycle Suction Pressure High ChecklistHarvest Valve Temperature Check General Harvest Valve AnalysisFindings Comments Discharge Line Temperature Analysis General Column 1 Harvest Valve Leaking Final AnalysisColumn 2 LOW CHARGE/TXV Starving Column 3 TXV FloodingModels Dual Expansion Valve Ice Machine Model Number Refrigeration System Operational Analysis TablesHigh Pressure CUT-OUT Hpco Control Self-Contained Water-Cooled Cycle Times S1800 SeriesHour Ice Production Operating PressuresConnections 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-DRIERSTotal System Refrigerant Charges Series Version Charge S1800M48 oz New Product Specifications RecoverRefrigerant Definitions RecycleRefrigerant RE-USE Policy Recovered or Recycled RefrigerantNew Refrigerant Reclaimed RefrigerantHFC Refrigerant Questions and Answers This page Intentionally Left Blank Page Attend a Manitowoc Factory Service School
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