Page 1 Ice Machines Service Manual PKU0155/PKM0335/PKM0425/PKM0535 MODELS PKU0155/PKM0335/PKM0425/PKM0535 MODELS For technical Assistance please call - MoTak Service @ 1-800.839.6754 Part Number: 000016427 Rev 00 01/2021...
Page 3 Safety Notices Read these precautions to prevent personal injury: • Read this manual thoroughly before operating, installing or performing maintenance on the equipment. Failure to follow instructions in this manual can cause property damage, injury or death. • Routine adjustments and maintenance procedures outlined in this manual are not covered by the warranty.
Page 4 Definitions DANGER Indicates a hazardous situation that, if not avoided, will result in death or serious injury. This applies to the most extreme situations. Warning Indicates a hazardous situation that, if not avoided, could result in death or serious injury. Caution Indicates a hazardous situation that, if not avoided, could result in minor or moderate injury.
Page 5 Warning Follow these electrical requirements during installation of this equipment: • All field wiring must conform to all applicable codes of the authority having jurisdiction. It is the responsibility of the end user to provide the disconnect means to satisfy local codes.
Page 6 Warning Follow these precautions to prevent personal injury while operating or maintaining this equipment: • Refer to nameplate to identify the type of refrigerant in your equipment. • Only trained and qualified personnel aware of the dangers are allowed to work on the equipment.
Page 7 Warning Follow these precautions to prevent personal injury during use and maintenance of this equipment: • It is the responsibility of the equipment owner to perform a Personal Protective Equipment Hazard Assessment to ensure adequate protection during maintenance procedures. • Do Not Store Or Use Gasoline Or Other Flammable Vapors Or Liquids In The Vicinity Of This Or Any Other Appliance.
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Page 9: Table Of Contents
Operational Checks PKM0335/PKM0425/PKM0535 ....28 Ice Thickness Check PKM0335/PKM0425/PKM0535 .... 28 Minimum/Maximum Slab Weights PKM0335/PKM0425/ PKM0535 ................28 Ice Making Sequence of Operation .......... 29 PKU0155 ................29 Energized Parts Chart PKU0155 ..........31 Part Number: 000016427 Rev 00 08/2020...
Page 10 Table of Contents (continued) Operational Checks PKU0155 ........... 32 Siphon System PKU0155 ............32 Water Level PKU0155 ............32 Water Level Check PKU0155 ..........33 Ice Thickness Check PKU0155 ..........33 Minimum/Maximum Slab Weight PKU0155 ......34 Troubleshooting PKM0335/PKM0425/PKM0535 Models Control Board Test Mode ............
Page 11 Refrigeration Component Diagnostic Chart ......89 Procedure ................89 Final Analysis ................ 90 Refrigeration Component Diagnostic Chart PKU0155 ..91 Ice Quality Is Poor — Cubes are Shallow, Incomplete or White ................93 Freeze Cycle Is Long, Low Ice Production ......94 Ice Machine Runs and No Ice Is Produced ......
Page 12 Refrigerant Charge .............. 116 Refrigerant Amount ............... 117 Ice Machine Normal Operation Charts ........117 PKU0155 Self Contained Ice Machine ......... 118 PKM0335 Modular Ice Machine ......... 119 PKM0425 Modular Ice Machine ......... 120 PKM0535 Modular Ice Machine ......... 121 Wiring Diagram ..............
Page 13: Requirements - Cleaning - Operation
Requirements - Cleaning - Operation Model Numbers This manual covers the following models: PKU0155SA - Small Cube, Air-cooled, Undercounter Model PKU0155FA - Full Cube Air-cooled, Undercounter Model PKM0335SA - Small Cube, Air-cooled, Modular Model PKM0335FA - Full Cube Air-cooled, Modular Model PKM0425SA - Small Cube, Air-cooled, Modular Model PKM0425FA - Full Cube Air-cooled, Modular Model PKM0535SA - Small Cube, Air-cooled, Modular Model...
Page 14: Location Of Ice Machine
Ice Machine Clearance Requirements PKU0155 Top and Sides 5" (13 cm) Back 5" (13 cm) PKM0335 Top and Sides 12" (30 cm) Back 5" (13 cm) PKM0425 and PKM0535 Top and Sides 8" (20 cm) Back 5" (13 cm) Do not obstruct ice machine vents or openings.
Page 15: Electrical Requirements
Requirements - Cleaning - Operation Ice Machine Heat of Rejection Series Heat of Rejection Air Conditioning Peak Ice Machine PKU0155 2200 2600 PKM0335 4600 5450 PKM0425 5400 6300 PKM0535 5300 6100 B.T.U./Hour Because the heat of rejection varies during the ice making cycle, the figure shown is an average.
Page 16: Water Service/Drains
Requirements - Cleaning - Operation Water Service/Drains WATER SUPPLY Local water conditions may require treatment of the water to inhibit scale formation, filter sediment, and remove chlorine odor and taste. Important If you are installing a water filter system, refer to the Installation Instructions supplied with the filter system for ice making water inlet connections.
Page 17: Water Supply And Drain Line Sizing/Connections
Requirements - Cleaning - Operation WATER SUPPLY AND DRAIN LINE SIZING/CONNECTIONS 40°F (4°C) min. Water Temperature 90°F (32.2°C) max. 20 psi (1.38 bar) min. Water Pressure 80 psi (5.5 bar) max. Ice Machine Fitting 3/8" Female Pipe Thread 3/8" (9.5 mm) min. Tubing Size Up to Ice Machine Fitting inside diameter Descaling and Sanitizing...
Page 18 Refer to the proper parts removal for your machine. Continue with Step 6 when the parts have been removed. Refer to “PKM0335/PKM0425/PKM0535 Parts Removal” on page 20 or “PKU0155 Parts Removal” on page 21. Step 6 Mix a solution of cleaner/descaler and lukewarm water. Depending on the amount of mineral buildup, a larger quantity of solution may be required.
Page 19: Sanitizing Procedure
Step 15 Wait until the water trough refills, then add the proper amount of ice machine sanitizer to the water trough. Model Amount of Sanitizer PKU0155 2.2 ounces (66 ml) PKM0335/PKM0425/PKM0535 3 ounces (90 ml) After the sanitize cycle is complete move the toggle switch to the ice position to start ice making.
Page 20: Remove Parts For Cleaning/Descaling
Requirements - Cleaning - Operation REMOVE PARTS FOR CLEANING/DESCALING Warning Disconnect electric power to the ice machine at the electric switch box before proceeding. PKM0335/PKM0425/PKM0535 Parts Removal A. Remove the water curtain • Gently flex the curtain in the center and remove it from the right side. •...
Page 21 Requirements - Cleaning - Operation PKU0155 Parts Removal Remove Two Thumbscrews and Water Pump Cover. Remove the Vinyl Hose Connecting the Water Pump and Water Distribution Tube. Remove Water Pump: • Disconnect the water pump power cord. • Loosen the screws securing the pump mounting bracket to the bulkhead.
Page 22 Requirements - Cleaning - Operation Remove the Water Distribution Tube A. Loosen the two thumbscrews, which secure the distribution tube. B. Lift the right side of the distribution tube up off the locating pin. C. Slide the distribution tube back. D.
Page 23 Requirements - Cleaning - Operation Remove the ice damper • Grasp ice damper and apply pressure toward the left hand mounting bracket. • Apply pressure to the right-hand mounting bracket with thumb. • Pull ice damper forward when the right-hand ice damper pin disengages.
Page 24: Remedial Cleaning Procedure
Open the front door and move the toggle switch to the CLEAN or WASH position. Wait until the water trough refills (approximately 1 minute) and then add the proper amount of Ice Machine cleaner/descaler to the water trough. Model Amount of Cleaner/Descaler PKU0155 2 ounces (60 ml) PKM0335/PKM0425/PKM0535 5 ounces (150 ml) Step 3 After 1 minute place the toggle switch in the ICE position and close and secure the front door.
Page 25: Cleaning The Condenser Filter
• PKU0155 - Blow compressed air in both the incoming water and the drain openings in the rear of the ice machine to remove all water.
Page 26: Ice Making Sequence Of Operation
Requirements - Cleaning - Operation Ice Making Sequence of Operation PKM0335/PKM0425/PKM0535 NOTE: The toggle switch must be in the ICE position and the water curtain must be closed before the ice machine will start. Water Purge Cycle The ice machine purges any remaining water from the water trough down the drain. Freeze Cycle Prechill - The refrigeration system chills the evaporator before water flow over the evaporator starts.
Page 27: Control Board Timers Pkm0335/Pkm0425/Pkm0535
Requirements - Cleaning - Operation CONTROL BOARD TIMERS PKM0335/PKM0425/PKM0535 • The ice machine is locked into the freeze cycle for 6 minutes before a harvest cycle can be initiated. • The freeze time lock in feature is bypassed on the initial cycle (manual start or after a full bin/safety limit condition).
Page 28 Requirements - Cleaning - Operation Safety Limit 2 If the harvest time reaches 3.5 minutes, the control board automatically returns the ice machine to the freeze cycle. • If three consecutive 3.5 minute harvest cycles occur the SL#2 light on the control board will flash on/off at 1 second intervals.
Page 29: Energized Parts Chart Pkm0335/Pkm0425/Pkm0535
Requirements - Cleaning - Operation ENERGIZED PARTS CHART PKM0335/PKM0425/PKM0535 ICE MAKING Compressor Water Harvest SEQUENCE Water Harvest Dump & Thickness Length of Inlet Float Pump Valve Valve Condenser Float Time Valve Switch OPERATION Fan Motor* Switch Initial Closed Closed 45 seconds Start-up 1a.
Page 30: Operational Checks Pkm0335/Pkm0425/Pkm0535
Requirements - Cleaning - Operation Operational Checks PKM0335/PKM0425/PKM0535 ICE THICKNESS CHECK PKM0335/PKM0425/PKM0535 After a harvest cycle, inspect the ice cubes in the ice storage bin. The ice bridge connects the ice cubes and must be set to maintain an ice bridge thickness of 1/8" (3 mm). To adjust the thickness of the bridge refer to ice thickness adjustment.
Page 31: Ice Making Sequence Of Operation
Requirements - Cleaning - Operation Ice Making Sequence of Operation PKU0155 NOTE: The toggle switch must be in the ICE position and the water curtain must be closed before the ice machine will start. Pressure Equalization Before the compressor starts the harvest valve is energized for 15 seconds to equalize pressures during the initial refrigeration system start-up.
Page 32 Requirements - Cleaning - Operation HARVEST SEQUENCE Harvest The water pump de-energizes stopping flow over the evaporator. The rising level of water in the sump trough diverts water out of the overflow tube, purging excess minerals from the sump trough. The harvest valve also opens to divert hot refrigerant gas into the evaporator.
Page 33: Energized Parts Chart Pku0155
Requirements - Cleaning - Operation ENERGIZED PARTS CHART PKU0155 Control Board Relays Relay ICE MAKING Length of SEQUENCE OF Water Harvest Relay Compressor Compressor Time OPERATION Pump Valve Coil Fan Motor* Initial Start-up 15 Second 1. Water Purge 2. Refrigeration...
Page 34: Operational Checks Pku0155
Requirements - Cleaning - Operation Operational Checks PKU0155 SIPHON SYSTEM PKU0155 To reduce mineral build-up and cleaning frequency, the water in the sump trough must be purged during each harvest cycle. When the water pump de-energizes, the level in the water trough rises above the standpipe, starting a siphon action.
Page 35: Water Level Check Pku0155
Requirements - Cleaning - Operation WATER LEVEL CHECK PKU0155 The float valve is factory-set for the proper water level. If adjustments are necessary: Verify the ice machine is level. Remove the siphon cap from the standpipe. Place the main ON/OFF/WASH toggle switch to the ON position, and wait until the float valve stops adding water.
Page 36: Minimum/Maximum Slab Weight Pku0155
Requirements - Cleaning - Operation MINIMUM/MAXIMUM SLAB WEIGHT PKU0155 Adjust ice thickness to meet 1/8" (3 mm) bridge thickness and minimum/maximum weight per cycle. Model Minimum Ice Weight Per Cycle Maximum Ice Weight Per Cycle 3.4 lbs 3.9 lbs PKM0335...
Page 37: Pkm0335/Pkm0425/Pkm0535 Models
Troubleshooting PKM0335/PKM0425/PKM0535 Models Control Board Test Mode NOTE: The water curtain/bin switch can be open or closed and does not affect the operation of the test mode. To enter the test mode, move the toggle switch to off, then press and hold the test button on the control board for 3 seconds.
Page 38: Diagnosing An Ice Machine That Will Not Run
Troubleshooting Diagnosing an Ice Machine that Will Not Run Warning High (line) voltage is applied to the control board at all times. Removing the control board fuse or pressing the power button will not remove the power supplied to the control board.
Page 39 Troubleshooting Freeze Time Lock-In Feature The ice machine control system incorporates a freeze time lock-in feature. This prevents the ice machine from short cycling in and out of harvest. The control board locks the ice machine in the freeze cycle for six minutes. After six minutes a harvest cycle can be initiated.
Page 40: Ice Machine Cycles Into Harvest Before The Harvest Float Is Down/Closed
Troubleshooting Ice Machine Cycles Into Harvest Before the Harvest Float Is Down/Closed Step 1 Disconnect power to the ice machine, remove the electrical panel to allow viewing of the control board lights and disconnect the harvest float switch from the control board.
Page 41: Ice Production Check
Troubleshooting Ice Production Check The amount of ice a machine produces directly relates to the operating water and air temperatures. This means an ice machine with a 70°F (21°C) ambient temperature and 50°F (10°C) water produces more ice than the same ice machine with 90°F (32°C) ambient and 70°F (21°C) water.
Page 42: Installation/Visual Inspection Checklist
Troubleshooting Installation/Visual Inspection Checklist Ice machine is not level • Level the ice machine Condenser is dirty • Clean the condenser Water filtration is plugged (if used) • Install a new water filter Water drains are not run separately and/or are not vented •...
Page 43: Water System Checklist
Troubleshooting Water System Checklist A water-related problem often causes the same symptoms as a refrigeration system component malfunction. Example: A water dump valve leaking during the freeze cycle, a system low on charge, and a starving TXV have similar symptoms. Water system problems must be identified and eliminated prior to replacing refrigeration components.
Page 44: Ice Formation Pattern
Troubleshooting Ice Formation Pattern Evaporator ice formation pattern analysis is helpful in ice machine diagnostics. Analyzing the ice formation pattern alone cannot diagnose an ice machine malfunction. However, when this analysis is used along with the Refrigeration System Operational Analysis Table, it can help diagnose an ice machine malfunction. OUTLET INLET Example of Evaporator Tubing Routing...
Page 45: Safety Limits
Troubleshooting No Ice Formation The ice machine operates for an extended period, but there is no ice formation at all on the evaporator. Evaporator Tubing Routing Routing of the tubing on the back of the evaporator determines the ice fill pattern failure mode.
Page 46: Safety Limit 3
Troubleshooting SAFETY LIMIT 3 If the harvest float switch hasn’t opened for 10 continuous seconds within the first 4 minutes of the freeze cycle, the ice machine stops. • Safety Limit 3 is bypassed on the initial cycle (manual start or after a full bin/safety limit condition).
Page 47: Safety Limit Checklist
Troubleshooting SAFETY LIMIT CHECKLIST The following checklists are designed to assist the service technician in analysis. However, because there are many possible external problems, do not limit your diagnosis to only the items listed. Safety Limit #1 Freeze time exceeds 35 minutes for 6 consecutive freeze cycles. Possible Cause Checklist Improper installation •...
Page 48 Troubleshooting Refrigeration System • Non-OEM components • Improper refrigerant charge • Defective compressor • TXV starving or flooding (check bulb mounting) • Non-condensible in refrigeration system • Plugged or restricted high side refrigerant lines or component • Defective harvest valve Safety Limit #2 Harvest time exceeds 3.5 minutes for 100 Consecutive harvest cycles.
Page 49 Troubleshooting Safety Limit 3 The harvest float switch hasn’t opened for 10 continuous seconds in the first 4 minutes of the freeze cycle. Possible Cause Checklist Improper installation • Refer to “Installation/Visual Inspection Checklist” on page 42 Water System • Water dump valve •...
Page 50: Analyzing Discharge Pressure
Troubleshooting Analyzing Discharge Pressure Determine the ice machine operating conditions: Air temp. entering condenser ______° Air temp. around ice machine ______° Water temp. entering sump trough ______° Refer to “Ice Machine Normal Operation Charts” on page 119 for ice machine being checked.
Page 51: Discharge Pressure High Checklist
Troubleshooting DISCHARGE PRESSURE HIGH CHECKLIST Improper Installation • Refer to “Installation/Visual Inspection Checklist” on page 42 Condenser Air Flow • High inlet air temperature • Condenser discharge air re-circulation • Dirty condenser fins • Defective fan cycling control • Defective fan motor Improper Refrigerant Charge •...
Page 52: Analyzing Suction Pressure
Troubleshooting Analyzing Suction Pressure The suction pressure gradually drops throughout the freeze cycle. The actual suction pressure (and drop rate) changes as the air and water temperature entering the ice machine changes. These variables also determine the 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.
Page 53 Troubleshooting Procedure Step 1. Determine the ice machine operating conditions. Example: Air temp. entering condenser: 90°F/32.2°C Air temp. around ice machine: 80°F/26.7°C 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 checked.
Page 54: Suction Pressure High Checklist
Troubleshooting SUCTION PRESSURE HIGH CHECKLIST Improper Installation • Refer to “Installation/Visual Inspection Checklist” on page 42 Discharge Pressure • Discharge pressure is too high and is affecting suction pressure, refer to “Discharge Pressure High Checklist” on page 51 Improper Refrigerant Charge •...
Page 55: Harvest Valve
Troubleshooting Harvest Valve General The harvest valve is an electrically operated valve that opens when energized, and closes when de-energized. Normal Operation The valve is de-energized (closed) during the freeze cycle and energized (open) during the harvest cycle. The valve is positioned between the compressor discharge line and the evaporator and performs two functions: Prevents refrigerant from entering the evaporator during the freeze cycle.
Page 56: Harvest Valve Analysis
Troubleshooting HARVEST VALVE ANALYSIS The valve can fail in two positions: • Valve will not open in the harvest cycle. • Valve remains open during the freeze cycle. VALVE WILL NOT OPEN IN THE HARVEST CYCLE: Although the circuit board has initiated a harvest cycle, the evaporator temperature remains unchanged from the freeze cycle.
Page 57 Troubleshooting Findings Comments The inlet of the harvest valve is cool enough This is normal as the discharge line should to touch and the compressor discharge line always be too hot to touch and the harvest is hot. valve inlet, although too hot to touch during harvest, should be cool enough to touch Cool &...
Page 58: Comparing Evaporator Inlet/Outlet Temperatures
Troubleshooting Comparing Evaporator Inlet/Outlet Temperatures The temperatures of the suction lines entering and leaving the evaporator alone cannot diagnose an ice machine. However, comparing these temperatures during the freeze cycle, along with the Refrigeration System Operational Analysis Table, can help diagnose an ice machine malfunction.
Page 59: Discharge Line Temperature Analysis
Troubleshooting Discharge Line Temperature Analysis GENERAL Knowing if the discharge line temperature is increasing, decreasing or remaining constant can be an important diagnostic tool. Maximum compressor discharge line temperature on a normally operating ice machine steadily increases throughout the freeze cycle. Comparing the temperatures over several cycles will result in a consistent maximum discharge line temperature.
Page 60: Refrigeration Component Diagnostics
Troubleshooting Refrigeration Component Diagnostics All electrical and water related problems must be corrected before these charts will work properly. These tables must be used with charts, checklists and other references to eliminate refrigeration components not listed and external items and problems that will cause good refrigeration components to appear defective.
Page 61: Final Analysis
Troubleshooting FINAL ANALYSIS The column with the highest number of check marks identifies the refrigeration problem. Column 1 – Harvest Valve Leaking A leaking harvest valve must be replaced. Column 2 – Low Charge/TXV Starving Normally, a starving expansion valve only affects the freeze cycle pressures, not the harvest cycle pressures.
Page 62: Refrigeration Component Diagnostic Chart
Troubleshooting Refrigeration Component Diagnostic Chart Operational Analysis Ice Production Published 24 hour ice production________________ Calculated (actual) 24 hour ice production_______________ NOTE: The ice machine is operating properly if the ice fill pattern is normal and ice production is within 10% of charted capacity.
Page 63 Troubleshooting Operational Analysis Freeze Cycle If suction pressure is High or Low refer to freeze cycle high Suction Pressure or low suction pressure problem checklist to eliminate ________ ______ ______ problems and/or components not listed on this table before 1 minute Middle proceeding.
Page 64 Troubleshooting THIS PAGE INTENTIONALLY LEFT BLANK Part Number: 000016427 Rev 00 08/2020...
Page 65: Pku0155 Model
Troubleshooting PKU0155 Model Troubleshooting an Ice Machine Will Not Run Warning High (line) voltage is applied to the control board (terminals #2 and #4) at all times. Removing control board fuse or moving the toggle switch to OFF will not remove the power supplied to the control board.
Page 66: Troubleshooting Ice Thickness Control Circuitry
Troubleshooting Troubleshooting Ice Thickness Control Circuitry ICE MACHINE DOES NOT CYCLE INTO HARVEST WHEN WATER CONTACTS THE ICE THICKNESS CONTROL PROBE Step 1 Bypass the freeze time lock-in feature by moving the ON/OFF/WASH switch to OFF and back to ON. Wait until the water starts to flow over the evaporator. Step 2 Clip the jumper wire to the ice thickness probe and any cabinet ground.
Page 67 Troubleshooting Step 3 Disconnect the ice thickness probe from the control board terminal. Clip the jumper wire to the terminal on the control board and any cabinet ground. Monitor the harvest light. PROBE ICE THICKNESS CONNECTION PROBE JUMPER WIRE GROUND BIN SWITCH EVAPORATOR HARVEST LIGHT...
Page 68: Ice Machine Cycles Into Harvest Before Water Contact With The Ice Thickness Probe
Troubleshooting ICE MACHINE CYCLES INTO HARVEST BEFORE WATER CONTACT WITH THE ICE THICKNESS PROBE Step 1 Bypass the freeze time lock-in feature by moving the ON/OFF/WASH switch to OFF and back to ON. Wait until the water starts to flow over the evaporator, then monitor the harvest light.
Page 69: Ice Production Check
Troubleshooting Ice Production Check The amount of ice a machine produces directly relates to the operating water and air temperatures. This means an ice machine with a 70°F (21.2°C) ambient temperature and 50°F (10.0°C) water produces more ice than the same ice machine with 90°F (32.2°C) ambient and 70°F (21.2°C) water.
Page 70: Installation And Visual Inspection Checklist
Troubleshooting Installation and Visual Inspection Checklist Ice machine is not level Level the ice machine Condenser is dirty • Clean the condenser Water filtration is plugged (if used) • Install a new water filter Water drains are not run separately and/or are not vented •...
Page 71 Troubleshooting Vent tube is not installed on water outlet drain • See Installation Instructions Hoses, fittings, etc., are leaking water • Repair/replace as needed Water float valve is stuck open or closed • Clean/replace as needed Water is spraying out of the sump trough area •...
Page 72: Ice Formation Pattern
Troubleshooting Ice Formation Pattern Evaporator ice formation pattern analysis is helpful in ice machine diagnostics. Analyzing the ice formation pattern alone cannot diagnose an ice machine malfunction. However, when this analysis is used along with the Refrigeration System Operational Analysis Table, it can help diagnose an ice machine malfunction. Any number of problems can cause improper ice formation.
Page 73 Troubleshooting Extremely Thin at Evaporator Outlet There is no ice, or a considerable lack of ice formation on the outlet of the evaporator. Examples: No ice at all at the outlet of the evaporator, but ice forms at the inlet half of the evaporator.
Page 74: Safety Limit Feature
Troubleshooting Safety Limit Feature In addition to the standard safety controls, your Koolaire® ice machine features built-in safety limits that will stop the ice machine if conditions arise which could cause a major component failure. Before calling for service, re-start the ice machine using the following procedure: Move the ON/OFF/WASH switch to OFF and then back to ON.
Page 75 Troubleshooting Determining Which Safety Limit Stopped the Ice Machine: When a safety limit condition causes the ice machine to stop, the harvest light on the control board continually flashes on and off. Use the following procedures to determine which safety limit has stopped the ice machine.
Page 76 Troubleshooting ANALYZING WHY SAFETY LIMITS MAY STOP THE ICE MACHINE According to the refrigeration industry, a high percentage of compressor failure is a result of external causes. These can include flooding or starving expansion valves, dirty condensers, water loss to the ice machine, etc. The safety limits protect the ice machine (primarily the compressor) from external failures by stopping ice machine operation before major component damage occurs.
Page 77: Safety Limit Checklist
Troubleshooting SAFETY LIMIT CHECKLIST The following checklists are designed to assist the service technician in analysis. However, because there are many possible external problems, do not limit your diagnosis to only the items listed. Safety Limit #1 Freeze time exceeds 60 minutes for 6 consecutive freeze cycles. Possible Cause Checklist Improper Installation •...
Page 78 Troubleshooting Refrigeration System • Restricted condenser air flow • Condenser discharge air re-circulation • Dirty condenser fins • Non-OEM components • Improper refrigerant charge • Defective compressor • TXV starving or flooding (check bulb mounting) • Non-condensible in refrigeration system •...
Page 79 Troubleshooting Safety Limit #2 Harvest time exceeds 3.5 minutes for 6 Consecutive harvest cycles. Possible Cause Checklist Improper Installation • Refer to “Installation and Visual Inspection Checklist” on page 70 Water System • Water area (evaporator) dirty • Dirty/defective water dump valve •...
Page 80: Analyzing Discharge Pressure
Troubleshooting Analyzing Discharge Pressure Determine the ice machine operating conditions: Air temp. entering condenser ______° Air temp. around ice machine ______° Water temp. entering sump trough ______° Refer to “Ice Machine Normal Operation Charts” on page 119 for ice machine being checked.
Page 81: Discharge Pressure High Checklist
Troubleshooting DISCHARGE PRESSURE HIGH CHECKLIST Improper Installation • Refer to “Installation and Visual Inspection Checklist” on page 70 Restricted Condenser Air Flow • High inlet air temperature • Condenser discharge air re-circulation • Dirty condenser fins • Defective fan cycling control •...
Page 82: Analyzing Suction Pressure
Troubleshooting Analyzing Suction Pressure The suction pressure gradually drops throughout the freeze cycle. The actual suction pressure (and drop rate) changes as the air and water temperature entering the ice machine changes. These variables also determine the 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.
Page 83 Troubleshooting Procedure Step 1. Determine the ice machine operating conditions. Example: Air temp. entering condenser: 90°F/32.2°C Air temp. around ice machine: 80°F/26.7°C 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 checked.
Page 84: Suction Pressure High Checklist
Troubleshooting SUCTION PRESSURE HIGH CHECKLIST Improper Installation • Refer to “Installation and Visual Inspection Checklist” on page 70 Discharge Pressure • Discharge pressure is too high, and is affecting suction pressure, refer to “Discharge Pressure High Checklist” on page 81 Improper Refrigerant Charge •...
Page 85: Harvest Valve
Troubleshooting Harvest Valve General The harvest valve is an electrically operated valve that opens when energized, and closes when de-energized. Normal Operation The valve is de-energized (closed) during the freeze cycle and energized (open) during the harvest cycle. The valve is positioned between the receiver and the evaporator and performs two functions: Prevents refrigerant from entering the evaporator during the freeze cycle.
Page 86: Harvest Valve Analysis
Troubleshooting HARVEST VALVE ANALYSIS The valve can fail in two positions: • Valve will not open in the harvest cycle. • Valve remains open during the freeze cycle. VALVE WILL NOT OPEN IN THE HARVEST CYCLE Although the circuit board has initiated a harvest cycle, the evaporator temperature remains unchanged from the freeze cycle.
Page 87 Troubleshooting Use the following procedure and table to help determine if a harvest valve is remaining partially open during the freeze cycle. Wait five minutes into the freeze cycle. Feel the inlet of the harvest valve. Important Feeling the harvest valve outlet or across the harvest valve itself will not work for this comparison.
Page 88 Troubleshooting Findings Comments The inlet of the harvest valve is cool enough This is normal as the discharge line should to touch and the compressor discharge line always be too hot to touch and the harvest is hot. valve inlet, although too hot to touch during harvest, should be cool enough to touch Cool &...
Page 89: Comparing Evaporator Inlet/Outlet Temperatures
Troubleshooting Comparing Evaporator Inlet/Outlet Temperatures The temperatures of the suction lines entering and leaving the evaporator alone cannot diagnose an ice machine. However, comparing these temperatures during the freeze cycle, along with using the Refrigeration System Operational Analysis Table, can help diagnose an ice machine malfunction.
Page 90: Discharge Line Temperature
Troubleshooting Discharge Line Temperature GENERAL Knowing if the discharge line temperature is increasing, decreasing or remaining constant can be an important diagnostic tool. Maximum compressor discharge line temperature on a normally operating ice machine steadily increases throughout the freeze cycle. Comparing the temperatures over several cycles will result in a consistent maximum discharge line temperature.
Page 91: Refrigeration Component Diagnostic Chart
Troubleshooting Refrigeration Component Diagnostic Chart All electrical and water related problems must be corrected before these charts will work properly. These tables must be used with charts, checklists and other references to eliminate refrigeration components not listed and external items and problems that will cause good refrigeration components to appear defective.
Page 92: Final Analysis
Troubleshooting FINAL ANALYSIS The column with the highest number of check marks identifies the refrigeration problem. Column 1 – Harvest Valve Leaking A leaking harvest valve must be replaced. Column 2 – Low Charge/TXV Starving Normally, a starving expansion valve only affects the freeze cycle pressures, not the harvest cycle pressures.
Page 93: Refrigeration Component Diagnostic Chart Pku0155
Troubleshooting REFRIGERATION COMPONENT DIAGNOSTIC CHART PKU0155 Operational Analysis Ice Production Published 24 hour ice production________________ Calculated (actual) 24 hour ice production_______________ NOTE: The ice machine is operating properly if the ice fill pattern is normal and ice production is within 10% of charted capacity.
Page 94 Troubleshooting Operational Analysis Freeze Cycle If suction pressure is High or Low refer to freeze cycle high Suction Pressure or low suction pressure problem checklist to eliminate ________ ______ _____ problems and/or components not listed on this table before 1 minute Middle proceeding.
Page 95: Ice Quality Is Poor - Cubes Are Shallow, Incomplete Or White
Troubleshooting ICE QUALITY IS POOR — CUBES ARE SHALLOW, INCOMPLETE OR WHITE Ice machine is dirty • Clean and sanitize the ice machine Water filtration is poor • Replace the filter Water softener is working improperly (if applicable) • Repair the water softener Poor incoming water quality •...
Page 96: Freeze Cycle Is Long, Low Ice Production
Troubleshooting FREEZE CYCLE IS LONG, LOW ICE PRODUCTION Water temperature is too high • Connect to a cold water supply, verify check valves in faucets and other equipment are functioning correctly Dirty Condenser • Clean condenser High air temperature entering condenser •...
Page 97: Ice Machine Runs And No Ice Is Produced
Troubleshooting ICE MACHINE RUNS AND NO ICE IS PRODUCED No water to ice machine • Correct water supply Incorrect incoming water pressure • Water pressure must be 20-80 psi (1.4-5.5 bar) Excessive mineral buildup • Clean and sanitize the ice machine Ambient temperature is too high or low •...
Page 98 Troubleshooting THIS PAGE INTENTIONALLY LEFT BLANK Part Number: 000016427 Rev 00 08/2020...
Page 99: Specifications
Specifications Main Fuse Function The control board fuse stops ice machine operation if electrical components fail causing high amp draw. Specifications • The main fuse is 250 Volt, 3.15 amp. Warning High (line) voltage is applied to the control board at all times. Removing the control board fuse or cycling the toggle switch Off/On will not remove the power supplied to the control board.
Page 100: Bin Switch
Specifications Bin Switch Function Bin switch operation is controlled by the movement of the water curtain. The bin switch has two main functions: Terminating the harvest cycle and returning the ice machine to the freeze cycle. This occurs when the bin switch is opened and closed again within 30 seconds of opening during the harvest cycle.
Page 101: Float Switch
Specifications Float Switch Function Open and close to indicate to the control board the level of water in the water trough. Specifications Normally closed, float operated magnetic reed switch. The float switch contacts are closed in the down position. When water raises the float to the up position the magnet in the float opens the contacts.
Page 102 Specifications If the control board light does not respond to the float, proceed with Step 1 below. Disconnect power to the ice machine and pull the float switch and connector through the ice machine base and disconnect. Attach an ohm meter lead to each float switch wire. Place the float in the down position - The float switch must be closed.
Page 103: Compressor Electrical Diagnostics
Specifications Compressor Electrical Diagnostics The compressor does not start or will trip repeatedly on overload. Check Resistance (Ohm) Values NOTE: Compressor windings can have very low ohm values. Use a properly calibrated meter. Perform the resistance test after the compressor cools. The compressor dome should be cool enough to touch (below 120°F/49°C) to ensure that the overload is closed and the resistance readings will be accurate.
Page 104 Specifications Compressor Drawing Locked Rotor The two likely causes of this are: • Defective starting component • Mechanically seized compressor To determine which you have: Install high and low side gauge. Try to start the compressor. Watch the pressures closely. •...
Page 105: Fan Cycle Control
Specifications PTCR Operation Check Visually inspect the PTCR. Check for signs of physical damage. NOTE: The PTCR case temperature may reach 210°F (100°C) while the compressor is running. This is normal. Do not change a PTCR just because it is hot. Wait at least 10 minutes for the PTCR to cool to room temperature.
Page 106 Specifications Check Procedure Disconnect electrical power to the ice machine at the electrical service disconnect. Verify fan motor windings are not open or grounded, and fan spins freely. Connect manifold gauge to ice machine. Hook voltmeter in parallel across the fan cycle control, leaving wires attached. Reconnect electrical power to the ice machine and Cycle the toggle switch On.
Page 107: High Pressure Cutout (Hpco) Control
Specifications High Pressure Cutout (HPCO) Control Function Stops the ice machine if subjected to excessive high-side pressure. The HPCO control is normally closed, and opens on a rise in discharge pressure. Specifications Cut-out: 600 psig ±10 / 4137 kPa ±10 Cut-in: 450 psig ±10 / 3103 kPa ±10 (Must be below 450 psig / 3103 kPa to reset).
Page 108: Refrigerant Recovery/Evacuation
Specifications Refrigerant Recovery/Evacuation DEFINITIONS Recover To remove refrigerant, in any condition, from a system and store it in an external container, without necessarily testing or processing it in any way. Recycle To clean refrigerant for re-use by oil separation and single or multiple passes through devices, such as replaceable core filter-driers, which reduce moisture, acidity and particulate matter.
Page 109: Refrigerant Re-Use Policy
Specifications REFRIGERANT RE-USE POLICY Proper handling, re-use, and disposal of refrigerants during service procedures require recapturing refrigerants, not venting them to the atmosphere. It is not necessary, in or out of warranty, to reduce or compromise the quality and reliability of your customers’ products to achieve this. Important Koolaire assumes no responsibility for use of contaminated refrigerant.
Page 110 Specifications Recovered refrigerant must come from a “contaminant-free” system. To decide whether the system is contaminant free, consider: • Type(s) of previous failure(s) • Whether the system was cleaned, evacuated and recharged properly following failure(s) • Whether the system has been contaminated by this failure •...
Page 111: Recovery And Recharging Procedures
Specifications RECOVERY AND RECHARGING PROCEDURES Do not purge refrigerant to the atmosphere. Capture refrigerant using recovery equipment. Follow the manufacturer’s recommendations. Important No responsibility is assumed for the use of contaminated refrigerant. Damage resulting from the use of contaminated refrigerant is the sole responsibility of the servicing company.
Page 112 Specifications CHARGING PROCEDURES Important The charge is critical on this equipment. Use a scale to ensure the proper charge is installed. Cycle the toggle switch Off. Isolate the vacuum pump valve, low side and high side access valves from the refrigeration system.
Page 113: System Contamination Cleanup
Specifications SYSTEM CONTAMINATION CLEANUP This section describes the basic requirements for restoring contaminated systems to reliable service. Important No responsibility is assumed for the use of contaminated refrigerant. Damage resulting from the use of contaminated refrigerant is the sole responsibility of the servicing company.
Page 114 Specifications Contamination/Cleanup Chart Symptoms/Findings Required Cleanup Procedure No symptoms or suspicion of contamination Normal evacuation/recharging procedure Moisture/Air Contamination symptoms Mild contamination cleanup procedure Refrigeration system open to atmosphere for longer than 15 minutes Refrigeration test kit and/or acid oil test shows contamination No burnout deposits in open compressor lines...
Page 115: Cleanup Procedure
Specifications CLEANUP PROCEDURE Mild System Contamination Replace any failed components. If the compressor is good, change the oil. Replace the liquid line drier. NOTE: If the contamination is from moisture, use heat lamps during evacuation. Position them at the compressor, condenser and evaporator prior to evacuation. Do not position heat lamps too close to plastic components, or they may melt or warp.
Page 116: Severe System Contamination Cleanup Procedure
Specifications SEVERE SYSTEM CONTAMINATION CLEANUP PROCEDURE Remove the refrigerant charge. Remove the compressor and inspect the refrigeration lines. If burnout deposits are found, install a new harvest valve, replace the manifold strainer, TXV and harvest pressure regulating valve. Wipe away any burnout deposits from suction and discharge lines at compressor. Sweep through the open system with dry nitrogen.
Page 117: Liquid Line Filter Driers
Specifications 10. Charge the system with the proper refrigerant to the nameplate charge. 11. Operate the ice machine for one hour. Then, check the pressure drop across the suction line filter-drier. A. If the pressure drop is less than 1 psig the filter-drier should be adequate for complete cleanup.
Page 118: Replacing Pressure Controls Without Removing Refrigerant Charge
Specifications REPLACING PRESSURE CONTROLS WITHOUT REMOVING REFRIGERANT CHARGE This procedure reduces repair time and cost. Use it when any of the following components require replacement, and the refrigeration system is operational and leak-free. • Fan cycle control • High pressure cut-out control •...
Page 119: Refrigerant Amount
Specifications Refrigerant Amount NOTE: All models charged with R410A refrigerant. Nameplate information overrides all data in this chart. Model Air-Cooled PKU0155 14 oz - 397 g PKM0335 15 oz - 425 g PKM0425 16 oz - 454 g PKM0535 18 oz - 510 g Ice Machine Normal Operation Charts These charts are used as guidelines to verify correct ice machine operation.
Page 120: Pku0155 Self Contained Ice Machine
Specifications PKU0155 SELF CONTAINED ICE MACHINE NOTE: These characteristics may vary depending on operating conditions. CYCLE TIMES Freeze Time + Harvest Time = Total Cycle Time Freeze Time Air Temp. Entering Harvest Water Temperature °F/°C Condenser °F/°C Time 50/10 70/21...
Page 121: Pkm0335 Modular Ice Machine
Specifications PKM0335 MODULAR ICE MACHINE NOTE: These characteristics may vary depending on operating conditions. CYCLE TIMES Freeze Time + Harvest Time = Total Cycle Time Freeze Time Air Temp. Entering Harvest Water Temperature °F/°C Condenser °F/°C Time 50/10 70/21 90/32 70/21 13.3-15.5 16.0-18.6...
Page 122: Pkm0425 Modular Ice Machine
Specifications PKM0425 MODULAR ICE MACHINE NOTE: These characteristics may vary depending on operating conditions. CYCLE TIMES Freeze Time + Harvest Time = Total Cycle Time Freeze Time Air Temp. Entering Harvest Water Temperature °F/°C Condenser °F/°C Time 50/10 70/21 90/32 70/21 11.7-13.7 12.5-14.5...
Page 123: Pkm0535 Modular Ice Machine
Specifications PKM0535 MODULAR ICE MACHINE NOTE: These characteristics may vary depending on operating conditions. CYCLE TIMES Freeze Time + Harvest Time = Total Cycle Time Freeze Time Air Temp. Entering Harvest Water Temperature °F/°C Condenser °F/°C Time 50/10 70/21 90/32 70/21 10.0-11.8 12.5-14.6...
Page 124: Wiring Diagram
Specifications Wiring Diagram Warning Always disconnect power before working on electrical circuitry. Wiring Diagram Legend The following symbols are used on all of the wiring diagrams: Internal Compressor Overload (Some models have external compressor overloads) Fan Motor Run Capacitor (Some models do not incorporate fan motor run capacitor) Wire Number Designation (The number is marked at each end of the wire) —>>—...
Page 125: Pku0155 Wiring Diagram
Specifications PKU0155 WIRING DIAGRAM PKU0155 Control Board Fuse (22) Transformer (24) On/Off /Clean Switch Bin Switch (23) Bin Thermostat (20) (10) (11) High Pressure Cut Out Harvest Solenoid Valve (21) Contactor Coil Contactor Contacts Compressor Compressor Relay Compressor Start Capacitor...
Page 126: Pkm0335/Pkm0425/Pkm0535 Wiring Diagram
Specifications PKM0335/PKM0425/PKM0535 WIRING PKM0335/PKM0425/PKM0535 DIAGRAM Number Component Bin Switch Compressor Compressor Overload (20) WHT (99) (21) BLU (22) Compressor Run Capacitor (61) RED Condenser Fan Motor (77) RED (80) Condenser Fan Motor Run (60) BLK Capacitor (76) BLK Contactor Coil (57) GRY Contactor Contacts (98) GRY...
Page 127: Electronic Control Board
Specifications Electronic Control Board CONTROL BOARD SCHEMATIC Electronic Control Board PKM0335/ PKM0335/PKM0425/PKM0535 PKM0425/PKM0535 Number Component LED Water Pump Relay LED Compressor Relay LED Water Dump Valve Relay LED Harvest Solenoid Valve LED Clean Thermistor Thermistor Thermistor LED Water Fill Valve LED Harvest Float LED Water Level Float LED Bin Switch...
Page 128: Control Board Schematic Pku0155
Specifications CONTROL BOARD SCHEMATIC PKU0155 Number Component Ice Thickness Probe Connector DC Low Voltage Electrical Connector Bin Switch Light Harvest Light Transformer Component Relays AC Line Voltage Electrical Connector 10 Amp Fuse Part Number: 000016427 Rev 00 08/2020...
Page 129: Refrigeration Tubing Schematic
Specifications Refrigeration Tubing Schematic PKU0155/PKM0335/PKM0425/PKM0535 Number Component Compressor Condenser-Air or Water cooled Receiver - Water Cooled Only Liquid Line Filter Drier Heat Exchanger TXV - Thermostatic Expansion Valve Evaporator Strainer Harvest Solenoid Valve Part Number: 000016427 Rev 00 08/2020...
Page 130 Specifications THIS PAGE INTENTIONALLY LEFT BLANK Part Number: 000016427 Rev 00 08/2020...
Page 132 Katom - 305 Katom Drive, Kodak, Tennessee 37764 Part Number: 000016427 Rev 00 08/2020...

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