Manitowoc MD0420A Technician'S Handbook Download Page 103

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Part Number 040005626 5/17

103

WATER REGULATING VALVE

Water-Cooled Models Only

FUNCTION

The water regulating valve maintains the freeze cycle
discharge pressure.

CHECK PROCEDURE

1. Determine if the head pressure is high or low

(refer to cycle time/24 hour ice production and
operational pressure chart for the model you are
servicing).

2. Verify the condenser water meets specifications.

3. Adjust valve to increase or decrease discharge

pressure.

4. Determine the temperature of the liquid line

entering the receiver by feeling it. This line is
normally warm; body temperature.

5. Using the information gathered, refer to the list for

diagnosis.

Problem (Freeze Cycle)

Valve not maintaining discharge pressure.

•

Valve incorrectly set, dirty or defective. Adjust,
clean or replace valve.

Discharge pressure extremely high; Liquid line
entering receiver feels hot.

•

Water regulating valve incorrectly set or not
opening.

Discharge pressure low, Liquid line entering
receiver feels warm to hot.

•

Ice machine low on charge. Verify Total System
Refrigerant Charge.

Summary of Contents for MD0420A

Page 1: ...Technician s Handbook This manual is updated as new information and models are released Visit our website for the latest manual www welbilt cn M series Ice Machines Part Number 040005626 5 17 Manitowoc ...

Page 2: ......

Page 3: ... Throughout this handbook you will see the following types of safety notices Warning Text in a Warning box alerts you to a potential personal injury situation Be sure to read the Warning statement before proceeding and work carefully Caution Text in a Caution box alerts you to a situation in which you could damage the equipment Be sure to read the Caution statement before proceeding and work caref...

Page 4: ...andbook you will see the following types of procedural notices NOTE Text set off as a Note provides you with simple but useful extra information about the procedure you are performing Important Text in an Important box provides you with information that may help you perform a procedure more efficiently Disregarding this information will not cause damage or injury but it may slow you down as you wo...

Page 5: ...ine adjustments and maintenance procedures outlined in this handbook are not covered by the warranty Warning 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 Warning Do not use electrical appliances or accessories other than those supplied by Manitowoc for your ...

Page 6: ...he refrigeration circuit when installing maintaining or servicing the unit Warning Do not operate equipment that has been misused abused neglected damaged or altered modified from that of original manufactured specifications This appliance is not intended for use by persons including children with reduced physical sensory or mental capabilities or lack of experience and knowledge unless they have ...

Page 7: ...nity of this or any other appliance Warning Do not clean with water jet Warning It is the responsibility of the equipment owner to perform a Personal Protective Equipment Hazard Assessment to ensure adequate protection during maintenance procedures Warning Two or more people are required to move this equipment to prevent tipping ...

Page 8: ...included Do not unplug by pulling on cord To unplug grasp the plug not the cord Unplug from outlet when not in use and before servicing or cleaning Do not operate any appliance with a damaged cord or plug or after the appliance malfunctions or is dropped or damaged in any manner Contact the nearest authorized service facility for examination repair or electrical or mechanical adjustment g Follow a...

Page 9: ...ce Machine Heat of Rejection 23 Leveling the Ice Machine 23 Electrical Requirements 24 Water Service Drains 25 Water Supply 25 Water Inlet Lines 25 Drain Connections 26 Cooling Tower Applications 26 MAINTENANCE Interior Cleaning and Sanitizing 29 General 29 Cleaning and Sanitizing Procedure 29 Toggle switch Operation 30 Remove Parts for Cleaning 34 Preventative Maintenance Cleaning 36 Ice Machine ...

Page 10: ...ontact with the Harvest Float Switch 51 Ice Machine Cycles Into Harvest Before Water loses Contact with the Harvest Float Switch 53 Ice Production Check 54 Installation Visual Inspection Checklist 55 Water System Checklist 56 Ice Formation Pattern 57 Safety Limits 60 Analyzing Discharge Pressure 67 Analyzing Suction Pressure 69 Harvest Valve 73 Comparing Evaporator Inlet Outlet Temperatures 77 Dis...

Page 11: ... Recharging Procedures 107 System Contamination Cleanup 110 Determining Severity of Contamination 110 Mild System Contamination Cleanup Procedure 112 Severe System Contamination Cleanup Procedure 113 Replacing Pressure Controls without Removing Refrigerant Charge 114 Refrigerant Amount 116 CHARTS Cycle Times 24 Hr Ice Production and Refrigerant Pressure Charts 117 M0420A Self contained Air cooled ...

Page 12: ... 17 DIAGRAMS Wiring Diagrams 127 Wiring Diagram Legend 127 M0420 M0500 M0700 M1000 1 PH Self contained Air Water cooled 128 Electronic Control Board 129 Refrigeration Tubing Schematics 130 Self contained Air or Water cooled 130 ...

Page 13: ...eral Information Model Numbers This manual covers the following models Self Contained Air Cooled Self Contained Water Cooled Remote MD0420A MY0420A MD0500A MY0500A MD0500W MD0700A MY0700A MD0600W MD1000A MY1000A MD1000W MY1000W MD1400A ...

Page 14: ...ty and refrigerant charge Repairs are to be performed by properly trained refrigeration technicians aware of the dangers of dealing with high voltage electricity and refrigerant under pressure A Air cooled W Water cooled Series Condenser Type Model M D 0500 A E R Regular D Dice Y Half dice Cube Size E WRAS 50Hz ...

Page 15: ...r workmanship under normal and proper use and maintenance as specified by the COMPANY and upon proper installation and start up in accordance with the instruction manual supplied with the ice machine The COMPANY s warranty hereunder with respect to the compressor and evaporator shall apply for an additional twenty four months excluding all labor charges The obligation of the COMPANY under this war...

Page 16: ...been subjected to misuse abuse neglect or accidents 3 any ice machine that has been installed and or maintained inconsistent with the technical instructions provided by the COMPANY or 4 any ice machine initially installed more than five years from the serial number production date This warranty shall not apply if the Ice Machine s refrigeration system is modified with a condenser heat reclaim devi...

Page 17: ...s from the installation date Authorized Warranty Service To comply with the provisions of the warranty a refrigeration service company qualified and authorized by your M series distributor or a Factory Authorized Servicer must perform the warranty repair Service Calls Normal maintenance adjustments and cleaning as outlined in this manual are not covered by the warranty ...

Page 18: ...AT ARE WELBILT S OBLIGATIONS UNDER THIS LIMITED WARRANTY If a defect arises and Welbilt receives a valid warranty claim prior to the expiration of the warranty period Welbilt shall at its option 1 repair the Product at Welbilt s cost including standard straight time labor charges 2 replace the Product with one that is new or at least as functionally equivalent as the original or 3 refund the purch...

Page 19: ...ized alterations modifications or changes and 5 defects or damage to any Product that has not been installed and or maintained in accordance with the instruction manual or technical instructions provided by Welbilt To the extent that warranty exclusions are not permitted under some state laws these exclusions may not apply to you Except As Stated In The Following Sentence This Limited Warranty Is ...

Page 20: ...t Tort Or Any Other Theory Of Liability Some states do not allow the exclusion or limitation of incidental or consequential damages so the above limitation or exclusion may not apply to you HOW STATE LAW APPLIES This limited warranty gives you specific legal rights and you may also have rights that vary from state to state or from one jurisdiction to another REGISTRATION CARD To secure prompt and ...

Page 21: ...heat generating equipment or in direct sunlight The location must be capable of supporting the weight of the ice machine and a full bin of ice The location must allow enough clearance for water drain and electrical connections in the rear of the ice machine The location must not obstruct airflow through or around the ice machine condenser air flow is in the back and out the sides Refer to the char...

Page 22: ...er Cooled and Remote Top Sides 8 20 3 cm 8 20 3 cm Back 5 12 7 cm 5 12 7 cm There is no minimum clearance required for water cooled or remote ice machines This value is recommended for efficient operation and servicing only Caution The ice machine must be protected if it will be subjected to temperatures below 32 F 0 C Failure caused by exposure to freezing temperatures is not covered by the warra...

Page 23: ...tion 1 1 B T U Hour Air Conditioning 2 2 Because the heat of rejection varies during the ice making cycle the figure shown is an average Ice machines like other refrigeration equipment reject heat through the condenser It is helpful to know the amount of heat rejected by the ice machine when sizing air conditioning equipment where self contained air cooled ice machines are installed Peak M0420 540...

Page 24: ...pacity The total circuit ampacity is used to help select the wire size of the electrical supply The wire size or gauge is also dependent upon location materials used length of run etc so it must be determined by a qualified electrician Refer to ice machine data plate for electrical requirements The ice machine data plate information overrides all other published data Warning All wiring must confor...

Page 25: ...stalled for other equipment are working Check valves on sink faucets dishwashers etc If water pressure exceeds the maximum recommended pressure 80 psig 5 5 bar obtain a water pressure regulator from your Manitowoc distributor Install a water shut off valve for ice making potable water Insulate water inlet lines to prevent condensation Important If you are installing a water filter system refer to ...

Page 26: ...water cooling tower installation does not require modification of the ice machine The water regulator valve for the condenser continues to control the refrigeration discharge pressure It is necessary to know the amount of heat rejected and the pressure drop through the condenser and water valves inlet to outlet when using a cooling tower on an ice machine Water entering the condenser must not exce...

Page 27: ...ter 3 8 9 5 mm min inside diameter Ice Machine Fitting 3 8 Female Pipe Thread 3 8 Female Pipe Thread 3 8 Female Pipe Thread Water Pressure 20 psi 1 38 bar min 80 psi 5 5 bar max 20 psi 1 38 bar min 150 psi 10 3 bar max Water Temperature 33 F 0 6 C min 90 F 32 2 C max 33 F 0 6 C min 90 F 32 2 C max Location Ice Making Water Inlet Condenser Water Inlet Condenser Water Drain ...

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Page 29: ...er treatment The ice machine must be taken apart for cleaning and sanitizing CLEANING AND SANITIZING PROCEDURE Ice machine cleaner is used to remove lime scale and mineral deposits Ice machine sanitizer disinfects and removes algae and slime Caution Use only Manitowoc approved Ice Machine Cleaner part number 94 0546 3 and Sanitizer part number 94 0565 3 It is a violation of Federal law to use thes...

Page 30: ...tting the ice machine to start ice making after the clean cycle Place the toggle switch in the Ice position more than 2 minutes into the clean cycle Step 1 Place the toggle switch in the clean position after ice falls from the evaporator at the end of a Harvest cycle Or place the toggle switch in the off position and allow the ice to melt off the evaporator Step 2 Remove all ice from the bin Cauti...

Page 31: ... minutes then place the toggle switch in the off position and disconnect power and water supplies to the ice machine Step 5 Remove parts for cleaning Refer to the proper parts removal for your machine Continue with step 6 when the parts have been removed Caution Do not mix Ice Machine Cleaner and Sanitizer solutions together It is a violation of Federal law to use these solutions in a manner incon...

Page 32: ...e foaming stops use a soft bristle brush sponge or cloth not a wire brush to carefully clean the parts Soak the parts for 5 minutes 15 20 minutes for heavily scaled parts Rinse all components with clean water Step 8 While components are soaking use half of the cleaner water solution to clean all foodzone surfaces of the ice machine and bin Use a nylon brush or cloth to thoroughly clean the followi...

Page 33: ...wing areas Evaporator plastic parts including top bottom and sides Bin bottom sides and top Do not rinse the sanitized areas Step 12 Replace all removed components Step 13 Wait 25 minutes Step 14 Reapply power and water to the ice machine and place the toggle switch in the ice position Step 15 Water will flow through the water dump valve and down the drain Wait until the water trough refills then ...

Page 34: ...ector is visible Disconnect the wire lead from the float switch Remove the float switch from the ice machine 4 Remove the water distribution tube NOTE Distribution tube thumbscrews are retained to prevent loss Loosen thumbscrews but do not pull thumbscrews out of distribution tube Loosen the two outer screws do not remove screws completely they are retained to prevent loss and pull forward on the ...

Page 35: ...5626 5 17 35 5 Remove the Water Trough Depress tabs on right and left side of the water trough Allow front of water trough to drop as you pull forward to disengage the rear pins Remove the water trough from the bin area ...

Page 36: ...t a cleaning cycle place the toggle switch in the clean position Water will flow through the water dump valve and down the drain Wait until the water trough refills then add the proper amount of ice machine cleaner to the water trough Step 3 Wait until the clean cycle is complete approximately 24 minutes then place the toggle switch in the off position Caution Never use anything to force ice from ...

Page 37: ... be adequate airflow through and around the ice machine to maximize ice production and ensure long component life Exterior Cleaning Clean the area around the ice machine as often as necessary to maintain cleanliness and efficient operation Sponge any dust and dirt off the outside of the ice machine with mild soap and water Wipe dry with a clean soft cloth Cleanup any fallen ice or water spills as ...

Page 38: ...hine a flashlight through the condenser to check for dirt between the fins Blow compressed air or rinse with water from the inside out opposite direction of airflow If dirt still remains call a service agent to clean the condenser Warning Disconnect electric power to the ice machine head section and the remote condensing unit at the electric service switches before cleaning the condenser Warning T...

Page 39: ...d the drain openings in the rear of the ice machine to remove all water 5 Place the toggle switch in the off position and disconnect the electric power at the circuit breaker or the electric service switch 6 Fill spray bottle with sanitizer and spray all interior food zone surfaces Do not rinse and allow to air dry 7 Replace all panels WATER COOLED MODELS 1 Perform steps 1 6 under Air Cooled Model...

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Page 41: ...ce thickness float switch is satisfied Freeze Water flowing across the evaporator freezes and builds ice on the evaporator After a sheet of ice has formed the Harvest float switch signals the control board to start a harvest cycle Harvest Cycle Any remaining water is purged down the drain as refrigerant gas warms the evaporator When the evaporator warms the sheet of cubes slides off the evaporator...

Page 42: ...nds during the start of a freeze cycle a harvest sequence is initiated The maximum freeze time is 60 minutes at which time the control board automatically initiates a harvest sequence The maximum harvest time is 3 5 minutes The control board automatically initiates a freeze sequence when these times are exceeded The ice machine will continue to fill with with water for up to six minutes or until t...

Page 43: ...cles control board light SL 1 light will flash on off at 1 second intervals If 6 consecutive 60 minute freeze cycles occur the ice machine stops and the SL 1 light on the control board will be on continuously 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 ...

Page 44: ... machine stops for 30 minutes when the water inlet valve is energized for 4 minutes and the harvest float valve didn t open Control board lights SL 1 and SL 2 will flash on off at 1 second intervals The ice machine automatically restarts at the end of the 30 minute delay period and stops flashing the control board lights If 100 consecutive failures occur the ice machine stops and the SL 1 SL 2 lig...

Page 45: ...ss Float Switch Length of Time Initial Start up 1a Water purge 1b Delay period ON ON OFF ON OFF CLOSED CLOSED 45 seconds OFF OFF OFF OFF OFF CLOSED CLOSED 5 seconds 2 Refrigeration System Start up 2a Equalize Pressure 2b Compressor Start up OFF ON OFF OFF OFF CLOSED CLOSED 5 seconds OFF ON OFF OFF ON CLOSED CLOSED 5 seconds Freeze Sequence 3 Pre chill OFF OFF ON OFF ON OPEN CLOSED 120 Seconds init...

Page 46: ... off 4 Freeze ON OFF ON OFF ON OPEN THEN CLOSED CLOSED THEN OPEN Until Harvest Float Switch closes for 10 continual seconds Harvest Sequence 5 Water Purge ON ON OFF ON ON CLOSED CLOSED 45 seconds 6 Harvest OFF ON OFF OFF ON CLOSED CLOSED Bin switch activation 7 Automatic Shut off OFF OFF OFF OFF OFF CLOSED CLOSED Until bin switch re closes ...

Page 47: ...kness at 1 8 3 mm NOTE Make sure the water curtain is in place when performing this check It prevents water from splashing out of the water trough 1 Inspect the bridge connecting the cubes It should be about 1 8 3 mm thick 2 If adjustment is necessary turn the ice thickness float switch clockwise to increase bridge thickness counterclockwise to decrease bridge thickness Adjust to achieve a 1 8 3 m...

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Page 49: ... board for 3 seconds The control board test mode performs the following functions for a 2 minute time period Energizes all control board relays Energizes all control board lights After 2 minutes the control board will automatically initiate and complete one ice making cycle then stop Canceling a test cycle To cancel a test cycle press the test button a second time Restarting a test cycle The test ...

Page 50: ...ull bin of ice 4 Verify toggle switch functions properly A defective toggle switch may keep the ice machine in the OFF mode Refer to toggle switch diagnostics when steps 1 3 test good 5 Be sure Steps 1 4 were followed thoroughly Intermittent problems are not usually related to the control board Replace control board if toggle switch operation is correct Warning High line voltage is applied to the ...

Page 51: ...efore the ice releases Remove all ice from the evaporator before starting diagnostic procedures 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 To a...

Page 52: ... On to cycle the ice machine on Wait until water flows over the evaporator then refer to chart Result Correction 10 seconds into the freeze cycle the ice machine cycles from freeze to harvest and the control board harvest light energizes The ice thickness float switch connectors or wiring are causing the malfunction The harvest light comes on but the ice machine remains in the freeze cycle The ice...

Page 53: ...he toggle switch to ice to bypass the freeze time lock in feature Wait until water flows over the evaporator then refer to chart Result Correction The harvest light does not come on and the ice machine stays in freeze The ice thickness float switch connectors or wiring are causing the malfunction Refer to float switch diagnostics 10 seconds into the freeze cycle the ice machine cycles from freeze ...

Page 54: ... in minutes Example 1 min 15 sec converts to 1 25 min 15 seconds 60 seconds 25 minutes Weights are in pounds Example 2 lb 6 oz converts to 2 375 lb 6 oz 16 oz 375 lb 3 Perform an ice production check using the formula below Weighing the ice is the only 100 accurate check 4 Compare the results of step 3 with step 2 Ice production is normal when these numbers match closely If they match closely dete...

Page 55: ...list 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 Run and vent drains according to the Installation Manual ...

Page 56: ... increase the water pressure Incoming water temperature is not between 35 F 1 7 C and 90 F 32 2 C If too hot check the hot water line check valves in other store equipment Water filtration is plugged if used Install a new water filter Vent tube is not installed on water outlet drain See Installation Instructions Hoses fittings etc are leaking water Repair replace as needed Water valve is stuck ope...

Page 57: ...mal Ice Formation Ice forms across the entire evaporator surface At the beginning of the Freeze cycle it may appear that more ice is forming on the inlet of the evaporator than at the outlet At the end of the Freeze cycle ice formation at the outlet will be close to or just a bit thinner than ice formation at the inlet The dimples in the cubes at the outlet of the evaporator may be more pronounced...

Page 58: ...ter loss low on refrigerant starving TXV faulty water inlet valve etc Extremely Thin at Evaporator Inlet There is no ice or a considerable lack of ice formation at the inlet of the evaporator Examples The ice at the outlet of the evaporator reaches the correct thickness but there is no ice formation at all at the inlet of the evaporator Possible cause Insufficient water flow flooding TXV etc No Ic...

Page 59: ...The evaporator outlet tubing does not exit directly at the top of the evaporator but exits several inches below the top of the evaporator Extremely Thin at the Evaporator Outlet will first be visible several inches below the top of the evaporator Extremely Thin at Evaporator Inlet will first be visible at the bottom of the evaporator Outlet Inlet Thin at Outlet Thin at Inlet ICE ICE ...

Page 60: ...cles control board light SL 1 light will flash on off at 1 second intervals If 6 consecutive 60 minute freeze cycles occur the ice machine stops and the SL 1 light on the control board will be on continuously 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 ...

Page 61: ... machine stops for 30 minutes when the water inlet valve is energized for 4 minutes and the harvest float valve didn t open Control board lights SL 1 and SL 2 will flash on off at 1 second intervals The ice machine automatically restarts at the end of the 30 minute delay period and stops flashing the control board lights If 100 consecutive failures occur the ice machine stops and the SL 1 SL 2 lig...

Page 62: ... 3 is indicated by both SL 1 SL 2 flashing After safety limit indication the ice machine will restart and run until a safety limit is exceeded again Safety Limit Notes A continuous run of 100 harvests automatically erases the safety limit code The control board will store and indicate only one safety limit the last one exceeded If the toggle switch is cycled OFF and then ON prior to reaching the 1...

Page 63: ... Inspection Checklist on page 55 Water System Float switch or water escaping water trough Low water pressure 20 psig min High water pressure 80 psig max High water temperature 90 F 32 2 C max Clogged water distribution tube Dirty defective water inlet valve Defective water pump Electrical System Harvest cycle not initiated electrically Contactor not energizing Compressor electrically non operation...

Page 64: ...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 ...

Page 65: ...System Water area evaporator dirty Dirty defective water dump valve Vent tube not installed on water outlet drain Water freezing behind evaporator Plastic extrusions and gaskets not securely mounted to the evaporator Electrical system Bin switch defective Premature harvest Refrigeration system Non OEM components Improper refrigerant charge Defective harvest valve TXV flooding check bulb mounting D...

Page 66: ...e Checklist Improper installation Refer to Installation Visual Inspection Checklist on page 55 Water System Water dump valve Harvest float valve dirty or defective Low water pressure 20 psig min Dirty defective water filter when used Loss of water from sump area Dirty defective water inlet valve Electrical system Water inlet valve coil defective Harvest float valve defective ...

Page 67: ...ssures Freeze Cycle ______ Harvest Cycle ______ 3 Perform an actual discharge pressure check 4 Compare the actual discharge pressure step 3 with the published discharge pressure step 2 The discharge pressure is normal when the actual pressure falls within the published pressure range for the ice machine s operating conditions It is normal for the discharge pressure to be higher at the beginning of...

Page 68: ...ensible in system Wrong type of refrigerant Other Non OEM components in system High side refrigerant lines component restricted before mid condenser Freeze Cycle Discharge Pressure Low Checklist Improper Installation Refer to Installation Visual Inspection Checklist on page 55 Improper Refrigerant Charge Undercharged Wrong type of refrigerant Other Non OEM components in system High side refrigeran...

Page 69: ...mperature 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 NOTE Analyze discharge pressure before analyzing suction pressure High or low discharge pressure may be causing high or low suction pressure ...

Page 70: ...eeze Cycle Suction Pressure psig In the example the proper suction pressure should be approximately 39 psig at 7 minutes 30 psig at 12 minutes etc 3 Perform an actual suction pressure check at the beginning middle and end of the freeze cycle Note the times at which the readings are taken Example Manifold gauges were connected to the example ice machine and suction pressure readings taken as follow...

Page 71: ...55 Discharge Pressure Discharge pressure is too high and is affecting suction pressure refer to Discharge Pressure High Checklist on page 68 Improper Refrigerant Charge Overcharged Wrong type of refrigerant Non condensible in system Other Non OEM components in system Harvest valve leaking TXV flooding check bulb mounting Defective compressor ...

Page 72: ... Pressure Low Checklist Improper Refrigerant Charge Undercharged Wrong type of refrigerant Other Non OEM components in system Improper water supply over evaporator refer to Water System Checklist on page 56 Loss of heat transfer from tubing on back side of evaporator Restricted plugged liquid line drier Restricted plugged tubing in suction side of refrigeration system TXV starving NOTE Do not limi...

Page 73: ...cycle The harvest valve is not used during the freeze cycle The harvest valve is de energized closed preventing refrigerant flow from the receiver into the evaporator 2 Allows refrigerant vapor to enter the evaporator in the harvest cycle During the harvest cycle the harvest valve is energized open allowing refrigerant gas from the discharge line of the compressor to flow into the evaporator The h...

Page 74: ...valve remaining partially open during the freeze cycle can be similar to symptoms of an expansion valve or compressor problem Symptoms are dependent on the amount of leakage in the freeze cycle A small amount of leakage will cause increased freeze times and an ice fill pattern that is Thin at the Outlet but fills in at the end of the cycle As the amount of leakage increases the length of the freez...

Page 75: ...pare the temperature of the inlet of the harvest valves to the temperature of the compressor discharge line 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 Warning The inlet of the harvest valve and the compress...

Page 76: ...st valve is hot and approaches the temperature of a hot compressor discharge line Hot Hot This is an indication something is wrong as the harvest valve inlet did not cool down during the freeze cycle If the compressor dome is also entirely hot the problem is not a harvest valve leaking but rather something causing the compressor and the entire ice machine to get hot Both the inlet of the harvest v...

Page 77: ...se temperatures must be within 7 F 4 C of each other Use this procedure to document freeze cycle inlet and outlet temperatures 1 Use a quality temperature meter capable of taking temperature readings on curved copper lines 2 Attach the temperature meter sensing device to the copper lines entering and leaving the evaporator 3 Wait five minutes into the freeze cycle 4 Record the temperatures below a...

Page 78: ...ir temperatures affect the maximum discharge line temperature Higher ambient air temperatures at the condenser higher discharge line temperatures at the compressor Lower ambient air temperatures at the condenser lower discharge line temperatures at the compressor Regardless of ambient temperature the freeze cycle discharge line temperature will be higher than 150 F 66 C on a normally operating ice...

Page 79: ...n valve sensing bulb is positioned and secured correctly Discharge Line Temperature Below 150 F 66 C at End of Freeze Cycle Ice machines that have a flooding expansion valve will have a maximum discharge line temperature that decreases each cycle Verify the expansion valve sensing bulb is 100 insulated and sealed airtight Condenser air contacting an incorrectly insulated sensing bulb will cause ov...

Page 80: ...rts checklists and other references to eliminate refrigeration components not listed and external items and problems that will cause good refrigeration components to appear defective The tables list four different defects that may affect the ice machine s operation NOTE A low on charge ice machine and a starving expansion valve have very similar characteristics and are listed under the same column...

Page 81: ...k all information listed Each item in this column has supporting reference material While analyzing each item separately you may find an external problem causing a good refrigerant component to appear bad Correct problems as they are found If the operational problem is found it is not necessary to complete the remaining procedures Step 2 Add the check marks listed under each of the four columns No...

Page 82: ...rge of refrigerant If the problem is corrected the ice machine is low on charge Find the refrigerant leak The ice machine must operate with the nameplate charge If the leak cannot be found proper refrigerant procedures must still be followed Change the liquid line drier evacuate the system and weigh in the proper charge If the problem is not corrected by adding charge the expansion valve is faulty...

Page 83: ...ed problems must be corrected before proceeding with chart Ice formation is normal or No ice formation on entire evaporator 3 Ice formation is normal or ice formation is extremely thin on the bottom of the evaporator or No ice formation on evaporator 2 Ice formation is extremely thin on outlet of evaporator or No ice formation on entire evaporator 1 Ice formation is extremely thin on outlet of eva...

Page 84: ... checklist to eliminate problems and or components not listed on this table before proceeding Suction pressure is High 3 Stops on safety limit 1 or 2 Suction pressure is High 2 Stops on safety limit 1 Suction pressure is Low 1 Stops on safety limit 1 or 2 Suction pressure is High Operational Analysis Safety limits Refer to Analyzing Safety Limits to eliminate all non refrigeration problems Freeze ...

Page 85: ...Flooding 2 The harvest valve inlet is COOL and The compressor discharge line is HOT Discharge line temp 150 F 66 C or higher at the end of freeze cycle Low On Charge or TXV Starving 1 The harvest valve inlet is HOT and The compressor discharge line is HOT Discharge line temp 150 F 66 C or higher at the end of freeze cycle Harvest Valve Leaking Operational Analysis Harvest Valve Discharge Line Temp...

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Page 87: ...light is on with the water curtain closed the fuse is good 2 Remove the fuse Check the resistance across the fuse with an ohmmeter 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 Warning Disconnect electrical power to the entire ice machine before proce...

Page 88: ...wn for 30 seconds the ice machine shuts off The ice machine remains off until enough ice is removed from the storage bin to allow the sheet of cubes to drop clear of the water curtain As the water curtain swings back to the operating position the bin switch closes and the ice machine restarts Check Procedure 1 Cycle the toggle switch OFF 2 Watch the curtain light on the control board 3 Move the wa...

Page 89: ...h 3 Cycle the bin switch open and closed numerous times by opening and closing the water curtain NOTE To prevent misdiagnosis Always use the water curtain magnet to cycle the switch a larger or smaller magnet will affect switch operation Watch for consistent readings when the bin switch is cycled open and closed bin switch failure could be erratic ...

Page 90: ...achine uses two float switches Ice Thickness Float Indicates the water level has been reached Harvest Float Indicates a harvest cycle needs to be initiated Initial testing can be performed by viewing the control board light s while raising and lowering the float The corresponding control board light must turn on and off when the float is raised and lowered Harvest Float switch A The light must be ...

Page 91: ... float switch wire 3 Place the float in the down position The float switch must be closed 4 Place the float in the up position The float switch must be open 5 If the float tests good ohm the interconnecting wires to the control board and inspect connectors NOTE Make adjustments with the ice machine in the off position Making adjustments during the freeze cycle may produce an initial sheet of ice t...

Page 92: ...om the compressor terminals 2 The resistance values between C and S and between C and R when added together should equal the resistance value between S and R 3 If the overload is open there will be a resistance reading between S and R and open readings between C and S and between C and R Allow the compressor to cool then check the readings again Check Motor Windings to Ground Check continuity betw...

Page 93: ... pressures do not move the compressor is seized Replace the compressor If the pressures move the compressor is turning slowly and is not seized Check the start components Compressor Drawing High Amps The continuous amperage draw on start up should not be near the maximum fuse size indicated on the serial tag The wiring must be correctly sized to minimize voltage drop at compressor start up The vol...

Page 94: ...ctrical 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 Wait until water flows over the evaporator then refer to chart below Cut In Close Cut Out Open 335 psig 5 2...

Page 95: ...CO leaving wires attached 4 On water cooled models close the water service valve to the water condenser inlet On self contained air cooled models disconnect the fan motor 5 Move toggle switch to ON 6 No water or air flowing through the condenser will cause the HPCO control to open because of excessive pressure Watch the pressure gauge and record the cut out pressure Replace the HPCO control if it ...

Page 96: ...unctions at night and or fails whenever the outdoor temperature drops A Safety limit is stored in control board memory Refrigerant loss and ambient temperature are directly related to each other As the ambient temperature drops more refrigerant is stored in the condenser When the refrigerant charge and ambient temperature create an undercharge of refrigerant in the freeze cycle the receiver dip tu...

Page 97: ...directly to the receiver HARVEST CYCLE OPERATION Remote Condenser Models The head pressure control cycles into full bypass due to the pressure drop when the harvest valve opens Refrigerant flows from the compressor to the evaporator through the harvest valve and the head pressure valve is out of the circuit Diagnostics FREEZE CYCLE REMOTE CONDENSER 1 Determine if the coil is clean 2 Determine the ...

Page 98: ...s and the ice machine malfunctions Lower ambient conditions can be simulated by rinsing the condenser with cool water during the freeze cycle Condition Probable Cause Corrective Measure Discharge Pressure High Liquid Line Temperature Hot Valve stuck in bypass Replace valve Discharge Pressure Low Liquid Line Temperature Cold Valve not bypassing Replace valve Discharge Pressure Low Liquid Line Tempe...

Page 99: ...re is low Harvest cycle discharge pressure is low Liquid line entering receiver feels warm to hot in the freeze cycle Overcharge Symptoms Safety limit 2 in control board memory a flashing triangle alert and after pressing left arrow long harvest is displayed Harvest cycle discharge pressure is normal Freeze cycle time suction and discharge pressure are normal and the ice machine will not harvest T...

Page 100: ...cally operated valve which opens when energized and closes when de energized Harvest pressure regulating valve HPR valve This is a pressure regulating valve which modulates open and closed based on the refrigerant pressure at the outlet of the valve The valve closes completely and stops refrigerant flow when the pressure at the outlet rises above the valve setting INLET OUTLET FLOW HPR SOLENOID SV...

Page 101: ...o liquid in the evaporator In general harvest cycle suction pressure rises then stabilizes Exact pressures vary from model to model Refer to cycle time 24 hour ice production and operational pressure charts HPR DIAGNOSTICS Steps 1 through 5 can be quickly verified without attaching a manifold gauge set or thermometer All questions must have a yes answer to continue the diagnostic procedure 1 Liqui...

Page 102: ...ischarge pressure and freeze harvest cycle times Refer to Freeze Cycle Refrigeration System Operational Analysis Tables for data collection detail 7 Freeze cycle Head Pressure is in the range indicated in the cycle time 24 hour ice production and operational pressure chart If the head pressure is low refer to head pressure control valve diagnostics 8 Freeze cycle Suction Pressure normal Refer to a...

Page 103: ...crease discharge pressure 4 Determine the temperature of the liquid line entering the receiver by feeling it This line is normally warm body temperature 5 Using the information gathered refer to the list for diagnosis Problem Freeze Cycle Valve not maintaining discharge pressure Valve incorrectly set dirty or defective Adjust clean or replace valve Discharge pressure extremely high Liquid line ent...

Page 104: ...eclaim To reprocess refrigerant to new product specifications see below by means which may include distillation A chemical analysis of the refrigerant is required after processing to be sure that product specifications are met This term usually implies the use of processes and procedures available only at a reprocessing or manufacturing facility Chemical analysis is the key requirement in this def...

Page 105: ...Must be of original nameplate type Must meet ARI Standard 700 latest edition specifications 3 Recovered or Recycled Refrigerant Must be recovered or recycled in accordance with current local state and federal laws Must be recovered from and re used in the same Manitowoc product Re use of recovered or recycled refrigerant from other products is not approved Recycling equipment must be certified to ...

Page 106: ...evacuated and recharged properly following failure s Whether the system has been contaminated by this failure Compressor motor burnouts and improper past service prevent refrigerant re use Refer to System Contamination Cleanup on page 110 to test for contamination 5 Substitute or Alternative Refrigerant Must use only Manitowoc approved alternative refrigerants Must follow Manitowoc published conve...

Page 107: ... the suction service valve 2 Discharge side of the compressor through the discharge service valve Important Manitowoc assumes no responsibility for the use of contaminated refrigerant Damage resulting from the use of contaminated refrigerant is the sole responsibility of the servicing company Important Replace the liquid line drier before evacuating and recharging Use only a Manitowoc O E M liquid...

Page 108: ...very unit or two stage vacuum pump 2 Perform recovery or evacuation A Recovery Operate the recovery unit as directed by the manufacturer s instructions B Evacuation prior to recharging Pull the system down to 500 microns Then allow the pump to run for an additional half hour Turn off the pump and perform a standing vacuum leak check ...

Page 109: ...emoved properly to ensure that no refrigerant contamination or loss occurs 8 Make sure that all of the vapor in the charging hoses is drawn into the ice machine before disconnecting the charging hoses A Run the ice machine in freeze cycle B Open the high and low side valves on the manifold gauge set Any refrigerant in the lines will be pulled into the low side of the system C Disconnect the low lo...

Page 110: ... or a similar diagnostic tool These devices sample refrigerant eliminating the need to take an oil sample Follow the manufacturer s directions If a refrigerant test kit indicates harmful levels of contamination or if a test kit is not available inspect the compressor oil 1 Remove the refrigerant charge from the ice machine 2 Remove the compressor from the system 3 Check the odor and appearance of ...

Page 111: ...r acid oil test shows contamination No burnout deposits in open compressor lines Mild contamination cleanup procedure Mild Compressor Burnout symptoms Oil appears clean but smells acrid Refrigeration test kit or acid oil test shows harmful acid content No burnout deposits in open compressor lines Mild contamination cleanup procedure Severe Compressor Burnout symptoms Oil is discolored acidic and s...

Page 112: ...ace the evacuation step with the following A Pull vacuum to 1000 microns Break the vacuum with dry nitrogen and sweep the system Pressurize to a minimum of 5 psig B Pull vacuum to 500 microns Break the vacuum with dry nitrogen and sweep the system Pressurize to a minimum of 5 psig C Change the vacuum pump oil D Pull vacuum to 500 microns Run the vacuum pump for 1 2 hour on self contained models 1 ...

Page 113: ...k the vacuum with dry nitrogen and sweep the system Pressurize to a minimum of 5 psig B Change the vacuum pump oil C Pull vacuum to 500 microns Break the vacuum with dry nitrogen and sweep the system Pressurize to a minimum of 5 psig D Change the vacuum pump oil E Pull vacuum to 500 microns Run the vacuum pump for 1 additional hour 10 Charge the system with the proper refrigerant to the nameplate ...

Page 114: ... feasible See the figure on next page Clamp down on the tubing until the pinch off is complete 3 Cut the tubing of the defective component with a small tubing cutter 4 Solder the replacement component in place Allow the solder joint to cool 5 Remove the pinch off tool 6 Re round the tubing Position the flattened tubing in the proper hole in the pinch off tool Tighten the wing nuts until the block ...

Page 115: ...Part Number 040005626 5 17 115 Using Pinch Off Tool SV1406 FIG A PINCHING OFF TUBING FIG B RE ROUNDING TUBING ...

Page 116: ... 040005626 5 17 Refrigerant Amount NOTE All models charged with R410A refrigerant Model Air Cooled Water Cooled M420 50 Hz 16oz 14oz M500 50 Hz 18oz 14oz M700 50 Hz 24oz 18oz M1000 50Hz 44oz 24oz M1400 50Hz 42oz 24oz ...

Page 117: ... are within 10 of the chart are considered normal This is due to variances in water and air temperature Actual temperatures will seldom match the chart exactly Refer to Operational Analysis Chart for the list of data that must be collected for refrigeration diagnostics Zero out manifold gauge set before obtaining pressure readings to avoid mis diagnosis Discharge and suction pressure are highest a...

Page 118: ...3 6 15 8 1 0 2 5 80 27 12 9 15 0 13 8 16 1 15 4 17 9 90 32 14 0 16 3 14 6 16 9 16 6 19 3 100 38 15 7 18 2 17 0 19 7 18 1 21 0 110 43 17 7 20 5 18 9 21 9 20 3 23 5 Air Temp Entering Condenser F C Water Temperature F C 50 10 70 21 90 32 70 21 370 350 325 80 27 340 320 290 90 32 315 305 270 100 38 285 265 250 110 43 255 240 225 Air Temp Entering Condenser F C Freeze Cycle Harvest Cycle Discharge Pres...

Page 119: ... 7 17 9 1 0 2 5 80 27 13 6 15 5 15 1 17 2 16 6 19 0 90 32 14 9 17 0 15 5 17 7 17 7 20 2 100 38 16 6 19 0 18 3 20 9 20 2 23 1 110 43 18 9 21 5 19 5 22 3 20 6 23 5 Air Temp Entering Condenser F C Water Temperature F C 50 10 70 21 90 32 70 21 495 425 385 80 27 440 400 365 90 32 405 390 345 100 38 365 335 305 110 43 325 315 300 Air Temp Entering Condenser F C Freeze Cycle Harvest Cycle Discharge Press...

Page 120: ...r Temperature F C 50 10 70 21 90 32 70 21 10 7 13 7 13 6 15 5 15 7 17 7 1 0 2 5 80 27 12 0 13 8 13 7 15 7 15 5 17 9 90 32 12 4 14 3 13 9 15 9 16 4 18 7 100 38 12 7 14 6 14 5 16 5 16 6 19 0 110 43 13 1 15 0 14 7 16 8 16 9 19 3 Air Temp Around Ice Machine F C Water Temperature F C 50 10 70 21 90 32 70 21 545 440 390 80 27 490 435 385 90 32 475 430 370 100 38 465 415 365 110 43 455 410 360 Air Temp A...

Page 121: ... 4 14 3 1 0 2 5 80 27 10 5 12 1 12 0 13 8 12 7 14 6 90 32 11 7 13 5 12 2 13 9 13 9 15 9 100 38 12 9 14 8 13 2 15 1 14 1 16 1 110 43 13 6 15 5 14 1 16 1 14 5 16 5 Air Temp Entering Condenser F C Water Temperature F C 50 10 70 21 90 32 70 21 600 510 475 80 27 550 490 465 90 32 500 485 430 100 38 460 450 425 110 43 440 425 415 Air Temp Entering Condenser F C Freeze Cycle Harvest Cycle Discharge Press...

Page 122: ...er Temperature F C 50 10 70 21 90 32 70 21 9 5 11 0 10 9 12 5 11 5 13 2 1 0 2 5 80 27 9 8 11 3 11 1 12 8 11 7 13 5 90 32 10 9 12 5 11 2 12 9 12 7 14 6 100 38 11 9 13 6 12 2 13 9 12 9 14 8 110 43 12 4 14 3 12 9 14 8 13 2 15 1 Air Temp Around Ice Machine F C Water Temperature F C 50 10 70 21 90 32 70 21 600 535 510 80 27 585 525 500 90 32 535 520 465 100 38 495 485 460 110 43 475 460 450 Air Temp Ar...

Page 123: ...6 12 6 1 0 2 5 80 27 9 4 11 1 10 2 12 1 10 9 12 9 90 32 10 2 12 1 11 0 13 0 12 0 14 2 100 38 11 1 13 1 12 6 14 8 13 1 15 5 110 43 12 1 14 3 13 0 15 4 13 9 16 4 Air Temp Entering Condenser F C Water Temperature F C 50 10 70 21 90 32 70 21 895 785 735 80 27 820 765 720 90 32 765 715 660 100 38 710 635 610 110 43 655 615 580 Air Temp Entering Condenser F C Freeze Cycle Harvest Cycle Discharge Pressur...

Page 124: ...ater Temperature F C 50 10 70 21 90 32 70 21 8 3 9 8 8 8 10 4 9 7 11 5 1 0 2 5 80 27 9 0 10 7 9 7 11 5 10 8 12 8 90 32 9 9 11 8 10 7 12 7 11 0 13 0 100 38 10 2 12 1 11 1 13 1 11 4 13 5 110 43 10 8 12 8 11 3 13 4 11 8 14 0 Air Temp Around Ice Machine F C Water Temperature F C 50 10 70 21 90 32 70 21 915 870 800 80 27 850 800 725 90 32 780 730 715 100 38 765 710 690 110 43 725 695 670 Air Temp Aroun...

Page 125: ...14 1 16 0 20 9 23 6 16 4 18 6 Air Temp Entering Condenser F C Water Temperature F C12 1 Base on average ice slab weight of 10 25 11 50lb 2 230 50 1 is approximately 12 lower than 230 60 1 50 10 70 21 90 32 70 21 1350 1245 1110 80 27 1245 1145 975 90 32 1175 975 910 100 38 1055 820 840 110 43 945 660 825 Air Temp Entering Condenser F C Freeze Cycle Harvest Cycle Discharge Pressure PSIG Suction Pres...

Page 126: ...126 Part Number 040005626 5 17 This Page Intentionally Left Blank ...

Page 127: ...he 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 Multi pin Connection Electrical Box Side Compressor Compartment Side Warning Always disconnect power before working ...

Page 128: ...128 Part Number 040005626 5 17 M0420 M0500 M0700 M1000 1 PH SELF CONTAINED AIR WATER COOLED ...

Page 129: ...040005626 5 17 129 ELECTRONIC CONTROL BOARD ICE LVL FLT BIN LEVEL TEST MODE HARVEST SAFETY 1 SAFETY 2 BIN LEVEL WTR LVL FLT WTR FLT ICE FLT TEST SW WTR PUMP COMPRESSOR WTR DUMP HARVEST CLEAN WATER FILL FUSE 3 15 A ...

Page 130: ...005626 5 17 Refrigeration Tubing Schematics SELF CONTAINED AIR OR WATER COOLED X HEAT EXCHANGER STRAINER DRIER EVAPORATOR HARVEST SOLENOID VALVE AIR OR WATER CONDENSER EXPANSION VALVE RECEIVER WATER COOLED ONLY COMPRESSOR ...

Page 131: ......

Page 132: ...Welbilt No 151 Jianye Road Binjiang District Hangzhou China 310011 Website www welbilt cn 2017 Manitowoc Part Number 040005626 5 17 ...

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Manitowoc MD0420A, Technician'S Handbook

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