Vulcan-Hart VHX24G5, MHB24G Water Level, Water Inlet Valve manual, Pressure Relief Valve

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Energized when Aux LLCO is satisfied and turns ready light (green) ON if high limit pressure switch is closed. Also, K1 allows K3 to be energized when the reset switch is pressed.

VHX SERIES STEAMERS - COMPONENT FUNCTION

Relay Board . . . . . . . . . . . . . . . . . . . Provides a centralized location for wire harness connections and power transfer through board relays (K1-K7) to the steamer controls. Also, provides a condition or component troubleshooting indicator by utilizing seventeen LED’S on the board to represent the status of the condition or component in the operation sequence. For an LED legend, see "RELAY BOARD" under "ELECTRICAL OPERATION". New style controls only.

NOTE: The relay’s below are mounted on the relay board and are not individually replaceable. K1 Relay . . . . . . . . . . . . . . . . . . . . . .

K2 Relay

Energized when high limit pressure switch is closed (high limit pressure

 

condition satisfied). When K1 & K2 are energized, the ready light (green)

 

will be ON.

 

K3 Relay

When Aux LLCO is satisfied and the manual reset switch is activated,

 

K3 is energized. When K3 is energized, turns water error light OFF and

 

allows the ignition sequence to begin. K3 must be energized for ignition

 

sequence to begin.

 

K4 Relay

Energized when K2 contacts are closed and manual reset switch is

 

activated. When K4 is energized, the high pressure light is OFF. When

 

K3 and K4 are both energized, power to the ignition system is supplied.

K5 Relay

Energized when operating conditions are met and reset switch is

 

activated. Provides power to start combustion blower.

K6 Relay

Energized by time delay circuit for approximately 15 seconds. When K6

 

and K7 are energized, power is supplied to the pilot gas valve.

K7 Relay

Energized when pilot voltage (PV) from the ignition module is present.

 

Also used in the time delay circuit.

 

Pilot

Ignites to light the main burner upon a call for heat.

Main Burner

Heats the water in the boiler to generate steam.

 

Water Level

 

 

 

 

Gauge Assembly

Permits a visual confirmation the water level is being maintained in

 

boiler during operation. The correct water level is approximately one

 

visible inch in the glass. The manual valves at the top and bottom of this

 

assembly must be fully open and only closed if the glass tube is

 

damaged.

 

Water Inlet Valve (manual)

The water inlet valve is used to stop water flow to the steamer when the

 

steamer is being serviced. This valve should remain open during normal

 

operation.

 

Inline Water Strainer

A "Y" strainer is installed upstream of the blowdown solenoid valve to

 

prevent foreign matter from becoming lodged in the valve. A strainer

 

(not supplied) should also be installed in the water supply line to prevent

 

foreign matter from becoming lodged in the fill or cold water condenser

 

solenoid valves and to keep unwanted particles out of the system.

Pressure Relief Valve

A mechanical device that opens to relieve steam pressure in the boiler if

 

the pressure exceeds 13 psi.

 

High Pressure Relief Valve

A back-up mechanical device that opens to relieve steam pressure in

 

the boiler if the pressure exceeds 15 psi.

 

Descaler

Hangs below the water level inside the boiler and is used to help control

 

boiler surface scaling. Two descalers are used in each boiler.

Boiler Pressure Gauge

Indicates the amount of steam pressure in the boiler.

Steam Header Assembly

Main steam supply line from the boiler to the steam header inlet in the

 

cooking control compartment.

 

 

 

Page 11 of 68

 

F24700 (October 2001)

 

 

 

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Contents VHX24G Shown VHX Boiler Base Series High Efficiency GAS SteamersTable of Contents VHX Series Steamers General InstallationMaintenance Cleaning Introduction Boiler Control Styles Electrical Water Conditioning SpecificationsSystem Water SupplySpecial ToolsGas Supply StandardVHX Series Steamers Operation Steamer OperationCabinet Base Boiler Cooking Compartment ControlsBoiler Blowdown Steamer Shut OFF Ignition Control Module Component FunctionVHX Series Steamers Component Function Blowdown/DrainPressure Relief Valve Steam Header AssemblyWater Level Water Inlet Valve manualSteam Supply Manifold Compartment Pressure SwitchSteam Solenoid Valve Manifold Pressure GaugeCabinet Base Boiler Controls Removal and Replacement of PartsVHX Series Steamers Removal and Replacement of Parts Component LocationsCabinet Base Boiler Controls Cooking Compartment Controls Water Level Controls Main or Auxiliary LlcoRelay Board Boiler Assembly Water Level Gauge AssemblyPressure Switches 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 Gasket Cooking Compartment DoorsRemoval Handle Latch AssemblyInspection Service Procedures and AdjustmentsClean-Out BoilerDescaler 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 Cooking Compartment Doors Intake Shut-Off Valve Adjustment Steam FlowDoor Sealing Adjustment Cooking CompartmentVHX Series Steamer Electrical Operation Door Latch AdjustmentLow Level Cut-Off & Differential Control Electrical OperationAuxiliary Low Level Cut-Off LED Legend Board Layout and LED LegendAux Water Level Satisfied State B Boiler Operational Status LED IndicatorReset Engaged State C Initial Conditions State aBurner ON, Boiler Heating to generate steam State E Air Pressure Switch Satisfied State DK32 Close K51 CloseHL-LED Sequence of OperationNEW Style Controls Boiler Initial Fill and PreheatN14, 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 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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