PARTS & SERVICE MANUAL
Contents
1. 20 Universal Tray Seal Panel o wo 840021 Upper Heater Subassembly x 640027 luminated Green Rooker Swich i 340023 Caution Hot Label IIQ nim ZIZrIxIS lt Xx E lt C H O0 8 MHC 1 Service Manual EXPLODED VIEW MODEL 86009 MHC 1 CONTROL PANEL O Timer Start Stop Button TIMER STARTS TOP Display Top Heating Element Indicator Light Green Indicator Light Green Time Button Temperature Button Bottom Heating Element Indicator Light Green Down Arrow Button Up Arrow Button NOTE For additional information concerning Menu and Product programming please refer to MHC 1 Operator Manual 10 MHC 1 Service Manual WIRING DIAGRAM Y 2000002 EYJU WOUJ CINTIA 15 ve 2 az YOSNIS JUNIVUIAMIHL COLH ICLH KIYM HOLINS IS vd 431Y3H ZH IH 014 WOLLOS 2018 018 dOL 1018 378Y9 NOBBIE HJIY3H H01108 YILVIH dOL O4WOB 1081 NO G4Y00 8 3INOd QUI SESSVHS 11 MHC 1 Service Manual Pom i Merco y y anitowoc STAR SERI RE PARK2. 40021 Upper Heater Subassembly 27T DD 840019 Lower Heater Subassemb DE 64000 ar Cover Pan O O O OOOO F 840008 Corset 6 0001708P Heyco Strain Relief Grommet H 340004 Rear Retention Rod tooo 340001 Heater Insulation Plate u o o Hex Washer SSS ore Top Bottominsuation bt 77 Leg w saoot4 ESE External Retaining Ring DON E Plasio Tray OOOO S DO 940016 Front Retention Rod SS SE o e a oons heater Piate Bracket O R 840107 Control Panel Label SSCS 8 640008 Side insulation To 540008 Ribbon Cable Subassembly u 8007 Side CoverPand SS DO v 540008 Power Conroe SSS w 640008 System Conroe SSS x 64002 iluminated Green Rooker Switch i 340023 Caution Hot Label TIOITIM ZISITIAR O lt x S lt lc ialow 6 MHC 1 Service Manual PARTS BREAKDOWN MODEL 86009 BB 340001 Heater Insulation Plate p 340008 Coms SSS S TE 00o1708P Heyco Strain Relief Grommet pF 340004 Rear Retention Rod e 340005 sensin OOOO Ho 84006 Power Control 7777S DO 84007 Side Cover Panel SSS u 840008 Ribbon Cable Subassembly kK 640008 System Contraer O SSS 1 640070 Control Panel Label SSS Du eela eg SSS DON 840012 Top Bottom insulation OOOO DO NC HexWashr OOOO p 540018 ES yo External Retaining ing a 400 Plate Ta OOOO DOR 640016 Front RetentionRod SSS DS som ig O DT 540018 Heater Plate Bracket u 640018 Lower Heater Subassemb DO v 8800
3. ee Merco PARTS amp SERVICE MANUAL MHC 1 Holding Cabinet Models 86007 amp 86009 Model 86009 shown P N L340134 REV 5 13 08 Merco LLC 1111 North Hadley Road Fort Wayne Indiana 46804 Telephone 260 459 8200 Fax 888 790 8193 Technical Support 800 678 9511 mercosavory com UNIT SPECIFICATIONS 86007 Left Side Control 120 VAC ME pot 6 NEMA 5 15P 86009 Right Side Control 120 VAC 60 41 6 NEMA 5 15P 2 MHC 1 Service Manual SEQUENCE OF OPERATIONS Power Supply Heating Circuit MHC 1 Service Manual Electrical power is supplied to the unit by a 3 conductor service for single phase 120VAC Black conductor is hot White conductor is neutral Green and yellow conductor is ground Power is permanently supplied to the main power switch Closing the main power switch supplies voltage to the power board and control board The control is set to the desired temperature The control then intermittently supplies 120VAC through the power board to the heater plates Temperature is then controlled by the two temperature sensors sending a reference signal back to the control board TROUBLESHOOTING GUIDE SYMPTOM POSSIBLE CAUSE EVALUATION Holding Cabinet will not heat Incoming Power Supply Verify power cord is secured firmly in receptacle Measure the incoming voltage Check circuit breakers Reset if required Call power company if needed Power Switch Check continuity between
4. page 2 for rating information If the amp draw is high or low check the individual elements for opens shorts and proper resistance WITH POWER OFF To check resistance of the elements remove all leads from the elements and use a digital multimeter The element resistance should be as follows 120V 87 ohms Replace heating element shelf as needed A i SS r 4 MHC 1 Service Manual TROUBLESHOOTING GUIDE CONT D iO G 6 Display reads Make sure wires are connected properly unusual characters grounded If wires are grounded properly new control board is needed On Off switch doesn t Power Switch Check wiring to switch light but unit works properly HEAT SHELF REPLACEMENT Disconnect power Take out screws holding L Brackets in cavity Disconnect thermocouple and all power connections to board Mark all wires for reassembly Take out power board Take out shelf mounting screws from both sides Remove shelves and feed wiring out of unit NPD i Be careful to avoid tearing the aluminum foil while working with wire MN WARNI NG connections 7 Reassemble in reverse order CONTROL BOARD REPLACEMENT Remove four 4 screws Disconnect ribbon cable Remove board When replacing U l board be sure ribbon cable is connected so that blue wire is facing towards interior of unit Reassemble in reverse order mar MHC 1 Service Manual 5 PARTS BREAKDOWN MODEL 86007 B 3
5. switch terminals Replace switch as needed Power Board Make sure wires are connected properly including ribbon cable Check ground wire green wires including main power cable Make sure the unit is grounded properly If everything is right replace TO O CSS control board JESS ag doesn t reach hereu a for continuity in circuit desired temperature Heat Element Compare cavity temperature with display reading Insert temperature probe into center of cavity Acceptable temperature variation is 20 from display reading Check for loose connection Check the Amp draw on each element for proper load Check page 2 for rating information If the amp draw is high or low check the individual elements for opens shorts and proper resistance WITH POWER OFF To check resistance of the elements remove all leads from the elements and use a digital multimeter The element resistance should be as follows 120V 87 ohms Replace heating element shelf as needed 2 thermostat common wire Please note if thermostat is pr m both circuits will be bad memso is too here a y ed rm for incorrectly wired thermocouple high Thermocouple wire polarities are reversed Heat Element Compare cavity temperature with display reading Insert temperature probe into center of cavity Acceptable temperature variation is 20 from display reading Check for loose connection Check the Amp draw on each element for proper load Check
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