Merco MHU63SST2N Service Manual Download

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Table of Contents

(continued)

Instructions For Replacing an IO Board ......................................................................................4-6

I/O Board Switch and Jumper Settings.......................................................................................4-6

I/O Board ...............................................................................................................................................4-7

Section 5

Troubleshooting

Troubleshooting ..............................................................................................................5-1

Zone Diagnostics ................................................................................................................................5-1

Power Issues Troubleshooting .......................................................................................................5-2

Communication Issues Troubleshooting ...................................................................................5-3

Temperature Too Low/Self Temp Low Issues Troubleshooting .........................................5-4

Temperature Too High Issues Troubleshooting .......................................................................5-5

Display Issues Troubleshooting .....................................................................................................5-6

ID Connector Issues Troubleshooting .........................................................................................5-7

Heater/Thermocouple Troubleshooting ....................................................................................5-8

Section 6

Wiring Diagrams

MHU63 -6x3 .....................................................................................................................6-1

Summary of Contents for MHU63SST2N

Page 1: ...Holding Cabinet MHU Service Manual This manual is updated as new information and models are released Visit our website for the latest manual Serving Quality on Demand Part Number MER_SM_8197925 09 2020 8197925 ...

Page 2: ...harm Operation installation and servicing of this product could expose you to airborne particles of glasswool or ceramic fibers crystalline silica and or carbon monoxide Inhalation of airborne particles of glasswool or ceramic fibers is known to the State of California to cause cancer Inhalation of carbon monoxide is known to the State of California to cause birth defects or other reproductive har...

Page 3: ...Screens 3 6 Setting Screens 3 9 Preferences Screen 3 10 Date Time Screen 3 10 Language Screen 3 11 Cabinet Names Screen 3 11 Zone Diagnostics Screens 3 12 Sound Screen Tests 3 12 Errors Log Screen 3 13 Password Settings Screen 3 13 System Information Screen 3 14 Utilities Screen 3 14 Load New Software Via USB 3 15 UI board Update 3 15 I O board Update 3 15 Section 4 Maintenance Cleaning and Saniti...

Page 4: ...ting 5 1 Zone Diagnostics 5 1 Power Issues Troubleshooting 5 2 Communication Issues Troubleshooting 5 3 Temperature Too Low Self Temp Low Issues Troubleshooting 5 4 Temperature Too High Issues Troubleshooting 5 5 Display Issues Troubleshooting 5 6 ID Connector Issues Troubleshooting 5 7 Heater Thermocouple Troubleshooting 5 8 Section 6 Wiring Diagrams MHU63 6x3 6 1 ...

Page 5: ...Qualified service personnel are those who are familiar with Merco equipment and who have been authorized by Merco to perform service on the equipment All authorized service personnel are required to be equipped with a complete set of service and parts manuals and to stock a minimum amount of parts for Merco equipment A list of Merco Factory Authorized Servicers FAS s is located on the Merco websit...

Page 6: ...ppliance without depending on or transmitting stress to the electrical conduit nWarning To avoid instability the installation area must be capable of supporting the combined weight of the equipment and product Additionally the equipment must be level side to side and front to back nWarning This equipment is intended for indoor use only Do not install or operate this equipment in outdoor areas The ...

Page 7: ...me loose during shipment and installation DANGER Copper wire suitable for at least 167 F 75 C must be used for power connections nWarning This appliance must be grounded and all field wiring must conform to all applicable local and national codes Refer to rating plate for proper voltage It is the responsibility of the end user to provide the disconnect means to satisfy the authority having jurisdi...

Page 8: ...ldingcabinetsurfaces may become hot during or after use Use utensils or protective clothing like pan grips or dry oven mitts when necessary to avoid burns nWarning DO NOT use the cavity for storage DO NOT leave paper products cooking utensils or food in the cavity when not in use Caution DO NOT cover racks or any other part of the holding cabinet with metal foil The Merco Visual Holding Cabinet ha...

Page 9: ... on zone pre heating will begin The press and go screen will be displayed Press Go Screen Pre Heating The unit will beep signaling that all holding zones are pre heated and ready for use Press Go Screen Each product tray must be wrapped with the correct identification band As the trays are loaded and recognized they will be highlighted in green and the product timer will start Press Go Screen with...

Page 10: ...e times runs out the corresponding tray timer will turn red and the alarm will beep Red Top Left Zone 9 Runs out of Hold Time The alarm will beep for 10 seconds The timer will display time the product is being held past programmed hold time Tray and food should be removed Reset the expired tray timer by selecting it Red Top Left Zone Runs Over Hold Time When necessary select a tray timer to reset ...

Page 11: ...equirements No line below the product name means no false bottom or a trivet is in the tray A dashed line below the product name means to use a false bottom A Group in the Menu A product in the menu is part of a group if there are dots underneath it or arrow heads on either side of it Select the menu item with the dots and the other items in the group will pop up and can be selected Swipe a produc...

Page 12: ...ll an active timer in the zone at the old temperature The shelf is waiting to warm up to the new temperature until all active timers at the old temperature are cleared New Menu with Active Timers from Last Menu Highlighted On press and go screen the lock icon disables the touch screen for 10 seconds The lock icon must be held for 1 second to disable the screen In the center of the lock graphic the...

Page 13: ...roduct and then the delete icon X A confirmation widow will pop up Select the green check to delete the product Select the red X to return to the menu screen Delete Product Confirmation Window When a product is edited or added required specifications include Name Hold Temp tray temperature maintained 5 F Product temp reference only not measured Hold time maximum time product can be held served War...

Page 14: ...e and product temp and can vary within a group From the menu screen select the group icon The group page lists programmed groups For the highlighted group group ID group name hold temperature zone split lid type and products included in the group are listed Group Icon Zone Splits 2 Group Screen If the group page is unlocked the delete edit and add icons will display on the group screen Unlocked De...

Page 15: ...k in to create the desired order When the edits are compete return to the group screen by selecting the X in the top left corner Zone Splits 1 To add a group select the group page add icon A pop up window will appear Click inside the name box and use the keyboard to enter the group name Select the return key bottom right and the keyboard will close NOTE Name groups so they are recognizable as grou...

Page 16: ...d to the zone Groups can also be added Zone split and zone temperatures will eliminate certain products Products not available will be grayed out Select the green check to save and return Zone Splits 2 Selecting A Product For Breakfast Zone 3 SETTING SCREENS From the home screen selecting the settings icon brings up the preferences screen This is the first of eleven setting screens There are eleve...

Page 17: ... If unchecked switching day parts in the press go screen from either display will switch the entire holding cabinet Font size can be adjusted between 24 48 Volume can be adjusted between 10 100 DATE TIME SCREEN To make changes on the this screen a passcode must be entered Select the lock on the bottom left of the screen Enter a passcode on the pop up number pad If the passcode is accepted there wi...

Page 18: ... language Only the headings and descriptions will change to the new language i e service page titles calendar month names product parameters and menu page titles CABINET NAMES SCREEN To make changes on the this screen a passcode must be entered Select the lock on the bottom left of the screen Enter a passcode on the pop up number pad If the passcode is accepted there will be a yellow ring around t...

Page 19: ...peratures The screen will have a red border while the testing Select Service Test to change the set temperatures to factory determined test temperatures OR Touch the a zone set temperature highlighted in white On the displayed numeric key pad enter the desired temperature then touch the green check Note Entering a temperature of 360 deg F or higher will cause the heating element to be ON all the t...

Page 20: ...D SETTINGS SCREEN Password Settings Screen There is a factory default manager passcode It can be changed on the password service screen Select the open box after Manager s and a new pin number pad will pop up Enter the new manager s passcode and the green check to confirm New Pin Number Pad To reset the passcode back to the factory default quickly touch the easy touch logo 10 times in a row At the...

Page 21: ...il returned to normal operation via this screen regardless of being powered off and on Export Menu Files Remove the USB port cover Plug a USB drive into your master external port Press the Export Menu Files button Restart unit Import Menu Files Remove the USB port cover Plug a USB drive with exported menu files into your master external port Press the Import Menu Files button Unit will only look f...

Page 22: ...date is complete 8 Remove the flash drive 9 Model MHU63 remove the cover of the unit insert UI USB into the secondary UI receptacle on the right side from the front in the top of the UI Then complete steps 6 8 10 Reinstall USB port cover and unit cover I O BOARD UPDATE The likelihood that the I O software will need to be updated is low 1 Turn the MHU on and wait until the power up sequence is comp...

Page 23: ...EXTERIOR CLEANING nWarning Never use a high pressure water jet for cleaning or hose down or flood interior or exterior of units with water Do not use power cleaning equipment steel wool scrapers or wire brushes on stainless steel or painted surfaces Caution Never use an acid based cleaning solution on exterior panels Many food products have an acidic content which can deteriorate the finish Be sur...

Page 24: ...cur proper dilution and rinsing per detergent manufacturers directions are mandatory Food approved detergents can be used if they are diluted per manufacturers directions and adequately rinsed away prior to high temp drying cycle Basic alcohols such as isopropyl are acceptable for hard to remove stains Otherwise do not use organic solvents DAILY CLEANING INSTRUCTIONS 1 You will need a damp cloth a...

Page 25: ...ot sudsy water non abrasive may be used 9 Wipe the interior with a damp cloth clean from the front and the back to reach all surfaces Pay attention to the ledges that support the trays If an excessive amount of food particles grease has collected hot sudsy water non abrasive may be used 10 Allow holding cabinet and trays to dry 11 Reinstall the cleaned trays 12 Plug the unit in ...

Page 26: ...4 4 Maintenance Section 4 Component Identification Power Supply Speaker Rear Controller Slave 2 I O board Slave 1 I O board I O Board Master Relay Front Controller Circuit Breaker Power Switch ...

Page 27: ... cabinet INSTRUCTIONS FOR REPLACING A TOUCH SCREEN 1 Disconnect the power 2 Remove the top of the cabinet 3 Disconnect any cables or wires from the rear of the touch screen marking their position for reassembly 4 Remove and replace the faulty touch screen 5 Remove the SD card from the failed controller by gently pushing in on the SD card and releasing until it is SD card is ejected The SD card is ...

Page 28: ...moved IO board see illustrations to the right and below and the on the following page 7 Carefully reattach all wires and harnesses 8 Replace the cabinet top and reconnect to power to return to service SW1 and J5 settings together define the system address I O Board Switch and Jumper Settings J5 Jumper Setting SW1 Setting ON 1 2 3 ON 1 2 3 ON 1 2 3 3 2 1 3 2 1 3 2 1 SW1 SW1 SW1 J5 J5 J5 Master IO S...

Page 29: ...ust be loaded with software A sticker will indicate when software is loaded and part number to indicate software version Thermocouple terminals Power to Heaters DIP switches Jumper switch To Slave IO Board From Master IO Board To Controller To Power Supply ...

Page 30: ...ture errors are displayed with on the affected zone see Figure 5 6 Press the return arrow to return to the home screen see Figure 6 7 Press the Press Go button to view the products see Figure 1 Section 5 Troubleshooting The software shall track the state of each thermocouple and the state of the thermocouple reading compared to the set point If the software finds an error it will begin to time it ...

Page 31: ... at the power cable connected to the relay power cord side 120V detected Replace the power cable N FAS ONLY Replace the power supply Y Turn on the unit and check if there is 120V at the switch connected to the relay switch side Y 120V detected Replace the switch N N Power Issues Troubleshooting Y Is 120V on the power supply side of the relay N Replace the relay ...

Page 32: ...s Page Y Issue exists Y Issue exists Y Y FAS ONLY Y IO board communication loss Y System Error Secondary UI communication loss Y FAS ONLY Change CANBus cable CANbus cable inserted Primary UI display active Issue exists See Display Issues Page Y Insert CANbus cable N N Y Issue exists Y Y System Error Primary UI communication loss Y FAS ONLY Communication Issues Troubleshooting See B on Display Issu...

Page 33: ... zones display N Y Thermocouple short error Unplug each thermocouple connected to the I O board one at a time If issue goes away note the heater position and replace the heater Verify 2 zones display Y Measured temp actual shelf temp 35F Remove shelf and press against the thermocouple and re install the shelf Measure the shelf temperature of the heater with an external temperature sensor Resistanc...

Page 34: ...r good N Wiring correct Y Y Y Replace heater N Replace I O board N Y Correct the wiring N Zone error Temperature too high FAS ONLY Multiple zones display N Y Thermocouple short error Unplug each thermocouple connected to the I O board one at a time If issue goes away note the heater position and replace the heater Verify 2 zones display Y Temperature Too High Issues Troubleshooting Y Y Insert the ...

Page 35: ...are Replace SD card with the latest SW Issue goes away after a reboot Replace the UI and reuse old SD card N N Y Touchscreen is black Touchscreen looks white with multiple colored lines Touchscreen responds very slowly or does not respond to touch B Issue exists Replace the touchscreen and reuse the old SD card Y Y Y Y Touchscreen is stuck on the Merco screen Replace SD card with the latest SW Iss...

Page 36: ...Change ID connector and reboot ID connector inserted Issue exists Y Insert ID connector and reboot N Y Issue exists Y Replace the touchscreen and reuse the SD card Invalid ID connector Y ID Connector Issues Troubleshooting FAS ONLY ...

Page 37: ...I O board triac could be shorted or open An orange LED is associated with each triac it signals if the triac should be on or off 6 Isolate each triac wire and check the amperage If the triac is supposed to be open and there is no current the problem could be a heater Check continuity through heating element If the triac light does not match the amperage the triac is failing and the I O board needs...

Page 38: ...6 1 Section 6 Wiring Diagrams MHU63 6x3 Wiring ...

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Page 40: ...g equipment and solutions Our cutting edge designs and lean manufacturing tactics are powered by deep knowledge operator insights and culinary expertise All of our products are backed by KitchenCare our aftermarket repair and parts service CLEVELAND CONVOTHERM DELFIELD FITKITCHEN FRYMASTER GARLAND KOLPAK LINCOLN MANITOWOC MERCO MERRYCHEF MULTIPLEX WWW WELBILT COM MERCO 8700 LINE AVENUE SHREVEPORT ...

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