Vulcan-Hart VHX24G Sequence of Operation, NEW Style Controls Boiler, Initial Fill and Preheat

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VHX SERIES STEAMER - ELECTRICAL OPERATION

SEQUENCE OF OPERATION

NEW STYLE CONTROLS - BOILER

This sequence of operation is written for boiler bases with the new style boiler controls. See "BOILER CONTROL STYLES" under "GENERAL". Refer to schematic diagram TSP1480.

Initial Fill and Preheat

Conditions.

A.Power switch OFF.

B.Boiler connected to correct voltage (120VAC).

C.Boiler properly grounded.

D.Gas and water supply valve(s) ON.

E.Main gas valve manual valve in ON position

F.Cycling pressure switch closed.

G.High limit pressure switch closed.

H.Cold water condenser (CWC) thermostat open.

I.Automatic blowdown solenoid valve (A.B.D.) open and boiler empty.

2.Turn power switch ON.

A.Automatic Blowdown valve (N.O.) is energized and close.

B.Water level control (WLC) energized.

1)High level (HL) relay energized, HL-3 contacts (N.O.) close.

a.Fill solenoid energized, water begins filling the boiler (fill time 4-11 min.).

2)HL LED lit.

C.Auxiliary water level control is powered.

1)Aux. LLCO N.O. contacts remain open.

D.120VAC to one side of K5(1) N.O., K1(1) N.O., K3(1) N.O., K4(1) N.O. contacts.

E.N6 lit. Low Water light (control panel) lit thru K3(1) N.C.

F.N8 lit. Hi Pressure light (control panel) lit thru K4(1) N.C.

G.N1 lit. 24VAC transformer is energized and relay board is powered.

1)24VAC to one side of auxiliary water level control LLCO contacts (N.O.).

2)N3 lit. K2 energized through the high

limit pressure switch contacts (N.C.).

a.K2 contacts K2(1) N.O. & K2(2) N.O. close, no power transferred.

3)N9 lit. 24VAC to one side of K3(2) N.O. contacts through cycling pressure switch N.C.

3.Water level reaches LLCO probe for both water level control and auxiliary low level control.

A.LLCO relay on water level board energizes, LLCO contacts (N.O.) close

1)LED on board lights.

B.Aux. LLCO relay energizes, aux. LLCO contacts (N.O.) close.

1)LED on board lights.

2)N2 lit. K1 is energized.

a.K1(1) N.O. close.

b.N4 lit. Ready light (green) on the control panel manual reset switch, ON.

3)K1(2) N.O. close.

NOTE: No power is transferred until manual reset switch pressed.

NOTE: The LLCO and aux. LLCO relays will remain energized and LLCO LED’S will remain lit until the water level drops below the LLCO probes or the power switch is turned OFF.

NOTE: The reset switch could be pressed to start combustion blower & ignition cycle but it’s preferred to let the boiler fill the to the "High Level" before continuing.

4.Water reaches LL (low level) probe.

5.Water reaches HL (high level) probe.

A.Fill solenoid is de-energized.

B.HL-LED

6.Manual reset switch pressed.

A.N5 lit. K3 is energized (120VAC).

NOTE: Relay K3 remains energized through K3(1) N.O. locking circuit.

1)N6 goes out. K3(1) N.O. contacts close and K3(1) N.C. contacts open.

2)Low water light (control panel) goes out.

3)N10 lit. K3(2) N.O. contacts close.

a.24VAC to one side of K4(2) N.O. contacts.

B.N7 lit. K4 is energized (120VAC).

F24700 (October 2001)

 

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Contents
VHX Boiler Base Series High Efficiency GAS Steamers VHX24G ShownTable of Contents VHX Series Steamers Maintenance Cleaning Introduction InstallationGeneral 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 Relay Board Water Level Controls Main or Auxiliary LlcoCooking Compartment Controls Pressure Switches Water Level Gauge AssemblyBoiler Assembly 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 Removal Cooking Compartment DoorsGasket 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 Control Auxiliary 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 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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