Vulcan-Hart MHB24G, VHX24G5 manual Ignition Control Module Checks, Terminals

Page 37

VHX SERIES STEAMER - SERVICE PROCEDURES AND ADJUSTMENTS

7.Once the correct pressure has been set, turn the gas supply and power switch OFF. Replace the adjustment screw cap and manifold pressure plug tap plug on the valve.

8.Turn the gas supply on and check for proper operation.

IGNITION CONTROL MODULE

CHECKS

1.Turn the power switch ON and allow the boiler to fill.

2.Aux. water level control satisfied and high limit closed.

3.Press the reset switch.

A.Combustion blower comes on and generates pressure to close the air pressure switch contacts.

B.Ignition control module is energized and trial for ignition starts. Check for 24VAC between terminals five and six.

C.Ignition module closes the internal pilot valve contacts. Check for 24 volts between terminals two and three.

1)High voltage is sent from terminal nine to the spark electrode and sparking begins.

2)At the same time, pilot timing circuit (control board) and pilot valve are both energized allowing gas flow to the pilot.

NOTE: The pilot valve will be energized by the relay board timer circuit for approximately 15 seconds to light the main burner.

D.Pilot ignition is established (pilot lit), and main gas valve is energized. Check for 24 volts between terminals one and two.

1)Sparking stops.

2)Ignition module monitors main burner flame.

3)After 15 seconds relay board timer times out.

a. Pilot valve de-energized.

E.As long as the ignition control module is sensing a burner flame through the ignition cable on terminal nine, the internal main voltage (MV) and pilot (PV) contacts (N.O.) remain closed.

NOTE: If pilot flame is not sensed within 15 seconds, you can re-start the ignition sequence.

F."Rapidly", turn the power switch OFF then ON. A rapid switching is needed to keep the boiler from starting automatic blowdown. Then press the reset button.

NOTE: If the power is not re-set, the ignition module continues sparking for a total of 90 seconds, then locks out. The module remains locked out until the power switch is turned to OFF then back ON and the reset switch is pressed to re-start the ignition trial cycle.

Terminals:

1.Main Valve - 24VAC will be present on terminal #1 with the flame sensing electrode sensing an adequate burner fame. This output voltage will remain present as long as the burner flame remains adequate.

2.MV/PV (common).

3.Pilot Valve - 24VAC will be present on terminal #3 at the instant an input voltage is supplied to the module. This output voltage will remain present on terminal #3 providing an adequate pilot flame is established within 90 seconds. In the event that an adequate pilot flame is not established within 90 seconds this output voltage will drop out.

4.Ground (burner).

5.24VAC Neutral (ground).

6.24VAC Input.

7.High Voltage to spark electrode. Provides high output voltage (13kv peak) to the spark electrode to light the gas pilot. Once pilot is lit, provides a path for flame current sensing by the Ignition Module via the spark electrode high voltage cable on terminal #9.

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F24700 (October 2001)

 

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Contents VHX24G Shown VHX Boiler Base Series High Efficiency GAS SteamersTable of Contents VHX Series Steamers Maintenance Cleaning Introduction InstallationGeneral Boiler Control Styles System Water Conditioning SpecificationsWater Supply ElectricalGas Supply ToolsStandard SpecialCabinet Base Boiler Steamer OperationCooking Compartment Controls VHX Series Steamers OperationBoiler Blowdown Steamer Shut OFF VHX Series Steamers Component Function Component FunctionBlowdown/Drain Ignition Control ModuleWater Level Steam Header AssemblyWater Inlet Valve manual Pressure Relief ValveSteam Solenoid Valve Compartment Pressure SwitchManifold Pressure Gauge Steam Supply ManifoldVHX Series Steamers Removal and Replacement of Parts Removal and Replacement of PartsComponent Locations Cabinet Base Boiler ControlsCabinet Base Boiler Controls Relay Board Water Level Controls Main or Auxiliary LlcoCooking Compartment Controls Pressure Switches Water Level Gauge AssemblyBoiler Assembly Boiler Fill and Cold Water Condenser Solenoid Valves Pilot GAS Valve Main GAS ValveComplete Burner Assembly Burner Head AssemblyHeat Exchanger VHX Series Steamers Removal and Replacement of Parts Removal Cooking Compartment DoorsGasket Handle Latch AssemblyClean-Out Service Procedures and AdjustmentsBoiler InspectionDescaler Cathodic Protector Water Level Probe Housing BlowdownTest Water Level ControlsAuxiliary Low level Cut-Off Control Cycling High LimitSmall increments Fill and Cold Water Solenoid ValvesBoiler BLOWDOWN/DRAIN Solenoid Valve Inline Water Strainer CleaningMain Burner Ignition Checks Pressure Switch AdjustmentGAS 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 Terminals Ignition Control Module ChecksSpark Verification Test Door Sealing Adjustment Intake Shut-Off Valve Adjustment Steam FlowCooking Compartment Cooking Compartment DoorsVHX Series Steamer Electrical Operation Door Latch AdjustmentLow Level Cut-Off & Differential Control Electrical OperationAuxiliary Low Level Cut-Off LED Legend Board Layout and LED LegendReset Engaged State C Boiler Operational Status LED IndicatorInitial Conditions State a Aux Water Level Satisfied State BK32 Close Air Pressure Switch Satisfied State DK51 Close Burner ON, Boiler Heating to generate steam State ENEW Style Controls Boiler Sequence of OperationInitial Fill and Preheat HL-LEDN14, N16, N17 go out N9, N10, N11, N12, N13 go outBoiler Blowdown/drain Water Refill After Initial FillVHX Series Steamer Electrical Operation Cooking Compartment Controls This page Intentionally Left Blank Models Built After 5/25/00 New Style Boiler Controls SchematicsVHX 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 VHX Series Steamer Troubleshooting TroubleshootingBoiler Base Controls Symptom Possible Causes Adjustments Boiler blowdown solenoid valve clogged and not fully closing Boiler Base Procedures and Adjustments VHX Series Steamer VHX Series Steamer Condensed Spare Parts List Condensed Spare Parts ListNEW Style Controls only VHX24G, VHX24G5, MHB24G
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