Vulcan-Hart VHX24G5, MHB24G manual Cooking Compartment Controls

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VHX SERIES STEAMER - ELECTRICAL OPERATION

upper and lower set point limits. The cycling pressure switch continues to energize and de-energize the heating circuit to cycle the burner ON and OFF.

This sequence continues until one of the following occurs:

1)Power switch is turned OFF.

2)Boiler water level drops below the LLCO probes for the main water level control and the auxiliary low level cut- off control

3)Boiler pressurizes to 15 PSI, causing the high limit pressure switch to OPEN.

Water Refill (After Initial Fill)

1.Water level drops below low level probe (LL).

A.HL relay is energized.

1)HL N.O. contacts CLOSE, fill solenoid is energized and HL LED comes ON.

2.Water reaches LL (low level) probe.

3.Water reaches high level probe.

A.HL relay is de-energized.

1)HL N.O. contacts OPEN, fill solenoid is de-energized and HL LED goes out.

4.The water refill cycle will occur whenever the water level is below the low level probe and will not affect the operation of either the preheat or cook cycle.

Boiler Blowdown/Drain

1.Power switch turned OFF.

A.Boiler blowdown sequence starts.

B.The automatic blowdown solenoid valve (N.O.) is de-energized and valve OPENS to drain the boiler.

C.Power is removed from all components except cold water condenser (CWC) thermostat and solenoid valve. The CWC thermostat cycles as necessary to lower the discharge temperature of the water and condense steam going into the drain.

COOKING COMPARTMENT CONTROLS

1.Conditions.

A.Doors shut (closes the N.O. door switch contacts).

B.Cooking timers OFF.

C.Compartment pressure switch contacts OPEN.

2.With boiler at operating pressure.

A.Cooking compartment pressure switch CLOSES (approx. 3 PSI).

1)Cooking compartment ready light (green) comes ON.

3.Start a cook cycle.

A.Insert product into steamer and close door.

B.Set a cook time.

NOTE: On initial startup, if a cooking timer is set immediately after the ready light comes on, steam solenoid chattering will be heard (oil canning) and the ready lights will flash for several seconds. This condition is caused by the manifold steam pressure being on the "fringe" of the pressure switch set point. When a cook timer is set, the compartment steam solenoid valve opens causing the manifold steam pressure to drop, slightly below the pressure switch set point. At the same time, steam pressure is still increasing in the boiler. This opposing condition causes a pressure "bounce" to occur. After the steam pressure passes approximately 4 psi this condition subsides. During normal operation, this condition will not be seen.

C.Contacts 1/3 of cook timer CLOSE and timer motor is energized.

1)Compartment steam solenoid valve energized and steam begins to enter the compartment.

2)Ready light (green) goes out and Cooking light (red) comes ON.

NOTE: Steam should not be seen entering either compartment until a cook time is set. This energizes the steam solenoid valve of the cooking compartment to allow steam flow.

4.Time expires on timer.

A.Timer contacts 1/3 OPEN, timer motor de- energized.

B.Steam solenoid valve de-energizes, stopping the flow steam into compartment.

C.Timer contacts 4/1 CLOSE and energize buzzer until manually turned OFF.

D.Cooking light (red) goes out and Ready light (green) comes ON.

5.Timer manually turned OFF.

A.Contacts 1/4 OPEN

B.Alarm Buzzer de-energized and stops buzzing.

6.Steamer reverts to preheat cycle until time is dialed on timer and the door is shut, water level drops below low level cut-off probe or the power switch is turned OFF.

F24700 (October 2001)

 

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Contents VHX Boiler Base Series High Efficiency GAS Steamers VHX24G ShownTable of Contents VHX Series Steamers General InstallationMaintenance Cleaning Introduction Boiler Control Styles Water Supply Water Conditioning SpecificationsSystem ElectricalStandard ToolsGas Supply SpecialCooking Compartment Controls Steamer OperationCabinet Base Boiler VHX Series Steamers OperationBoiler Blowdown Steamer Shut OFF Blowdown/Drain Component FunctionVHX Series Steamers Component Function Ignition Control ModuleWater Inlet Valve manual Steam Header AssemblyWater Level Pressure Relief ValveManifold Pressure Gauge Compartment Pressure SwitchSteam Solenoid Valve Steam Supply ManifoldComponent Locations Removal and Replacement of PartsVHX Series Steamers Removal and Replacement of Parts Cabinet Base Boiler ControlsCabinet Base Boiler Controls Cooking Compartment Controls Water Level Controls Main or Auxiliary LlcoRelay Board Boiler Assembly Water Level Gauge AssemblyPressure Switches Pilot GAS Valve Main GAS Valve Boiler Fill and Cold Water Condenser Solenoid ValvesBurner Head Assembly Complete Burner AssemblyHeat Exchanger VHX Series Steamers Removal and Replacement of Parts Gasket Cooking Compartment DoorsRemoval Latch Assembly HandleBoiler Service Procedures and AdjustmentsClean-Out InspectionWater Level Probe Housing Blowdown Descaler Cathodic ProtectorWater Level Controls TestAuxiliary Low level Cut-Off Control High Limit CyclingFill and Cold Water Solenoid Valves Small incrementsInline Water Strainer Cleaning Boiler BLOWDOWN/DRAIN Solenoid ValvePressure Switch Adjustment Main Burner Ignition ChecksGAS Manifold Pressure Adjustment VHX Series Steamer Service Procedures and Adjustments AIR Pressure Switch Adjustment GAS Pilot Pressure Adjustment Pressure Readings Inches W.C GAS Manifold Pressure Adjustment Ignition Control Module Checks TerminalsSpark Verification Test Cooking Compartment Intake Shut-Off Valve Adjustment Steam FlowDoor Sealing Adjustment Cooking Compartment DoorsDoor Latch Adjustment VHX Series Steamer Electrical OperationElectrical Operation Low Level Cut-Off & Differential ControlAuxiliary Low Level Cut-Off Board Layout and LED Legend LED LegendInitial Conditions State a Boiler Operational Status LED IndicatorReset Engaged State C Aux Water Level Satisfied State BK51 Close Air Pressure Switch Satisfied State DK32 Close Burner ON, Boiler Heating to generate steam State EInitial Fill and Preheat Sequence of OperationNEW Style Controls Boiler HL-LEDN9, N10, N11, N12, N13 go out N14, N16, N17 go outWater Refill After Initial Fill Boiler Blowdown/drainVHX Series Steamer Electrical Operation Cooking Compartment Controls This page Intentionally Left Blank Schematics Models Built After 5/25/00 New Style Boiler ControlsVHX Series Steamer Electrical Operation Models Built Before 5/25/00 Old Style Boiler Controls Cooking Compartment Controls Wiring Diagrams VHX Series Steamer Electrical Operation Models Built Before 5/25/00 Old Style Boiler Controls VHX Series Steamer Electrical Operation Cooking Compartment Controls Boiler Base Controls TroubleshootingVHX Series Steamer Troubleshooting Symptom Possible Causes Adjustments Boiler blowdown solenoid valve clogged and not fully closing Boiler Base Procedures and Adjustments VHX Series Steamer NEW Style Controls only VHX24G, VHX24G5, MHB24G Condensed Spare Parts ListVHX Series Steamer Condensed Spare Parts List
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