Troubleshooting, Boiler Base Controls | Vulcan-Hart VHX24G, MHB24G

VHX SERIES STEAMER - TROUBLESHOOTING

TROUBLESHOOTING

BOILER BASE CONTROLS

WARNING: CERTAIN PROCEDURES IN THIS SECTION REQUIRE ELECTRICAL TESTS OR MEASUREMENTS WHILE POWER IS APPLIED TO THE MACHINE. EXERCISE EXTREME CAUTION AT ALL TIMES. IF TEST POINTS ARE NOT EASILY ACCESSIBLE, DISCONNECT POWER, ATTACH TEST EQUIPMENT AND REAPPLY POWER TO TEST.

Models with new style controls: Before performing any of the troubleshooting checks listed below, remove the cover from the main control box and check the condition of the LED’S on the relay board for the status of the condition or component in the operating sequence. By utilizing the troubleshooting LED’S, the Service Technician can quickly and easily determine if a component is functioning properly or in need of repair. Refer to "RELAY BOARD" under "ELECTRICAL OPERATION".

	SYMPTOM		POSSIBLE CAUSES

	Steamer does not operate.	1.	No power to steamer.
		2.	F1 Fuse open.
		3.	Malfunctioning power switch.
		4.	Malfunctioning power switch latching relay (old style controls
			only).

	Steamer ON, cannot reset low water	1.	Low water level in boiler.
	condition.		A. Water inlet valve(s) OFF.
			B. Fill solenoid not receiving power, clogged or
			malfunctioning.
		2.	Manual blowdown valve on water level probe housing open.
		3.	Improper ground.
		4.	Lime scale build-up auxiliary water level probe.
		5.	Malfunctioning reset switch.
		6.	Malfunctioning auxiliary water level control board.

	Steamer ON, cannot reset high pressure	1.	Excessive pressure in boiler.
	condition.	2.	Malfunctioning reset switch.
		3.	Malfunctioning high pressure limit switch.
		4.	Malfunctioning pressure switch latching relay (old style controls
			only).

	Steamer ON, reset switch pressed but	1.	Blower malfunctioning or loose connection on blower cord.
	blower does not operate when calling for	2.	24 VAC transformer malfunctioning.
	heat.	3.	Malfunction in cycling pressure switch.
	(boiler pressure within operating limits)	3.	Malfunction in cycling pressure switch.
	(boiler pressure within operating limits)	4.	Malfunctioning "Low Water" or "Hi Pressure" light not indicating
		4.
			true condition.
		5.	Blower relay malfunctioning (old style controls only).

Page 61 of 68		F24700 (October 2001)

Image 61

Vulcan-Hart MHB24G, VHX24G5 manual Boiler Base Controls, VHX Series Steamer Troubleshooting

Contents

VHX24G Shown VHX Boiler Base Series High Efficiency GAS Steamers Table of Contents VHX Series Steamers Maintenance Cleaning Introduction InstallationGeneral Boiler Control Styles System Water Conditioning SpecificationsWater Supply Electrical Gas Supply ToolsStandard Special Cabinet Base Boiler Steamer OperationCooking Compartment Controls VHX Series Steamers Operation Boiler Blowdown Steamer Shut OFF VHX Series Steamers Component Function Component FunctionBlowdown/Drain Ignition Control Module Water Level Steam Header AssemblyWater Inlet Valve manual Pressure Relief Valve Steam Solenoid Valve Compartment Pressure SwitchManifold Pressure Gauge Steam Supply Manifold VHX Series Steamers Removal and Replacement of Parts Removal and Replacement of PartsComponent Locations Cabinet Base Boiler Controls Cabinet 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 Valve Complete Burner Assembly Burner Head Assembly Heat Exchanger VHX Series Steamers Removal and Replacement of Parts Removal Cooking Compartment DoorsGasket Handle Latch Assembly Clean-Out Service Procedures and AdjustmentsBoiler Inspection Descaler Cathodic Protector Water Level Probe Housing Blowdown Test Water Level Controls Auxiliary Low level Cut-Off Control Cycling High Limit Small increments Fill and Cold Water Solenoid Valves Boiler BLOWDOWN/DRAIN Solenoid Valve Inline Water Strainer Cleaning Main Burner Ignition Checks Pressure Switch Adjustment GAS 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 Checks Spark Verification Test Door Sealing Adjustment Intake Shut-Off Valve Adjustment Steam FlowCooking Compartment Cooking Compartment Doors VHX Series Steamer Electrical Operation Door Latch Adjustment Low Level Cut-Off & Differential Control Electrical Operation Auxiliary Low Level Cut-Off LED Legend Board Layout and LED Legend Reset Engaged State C Boiler Operational Status LED IndicatorInitial Conditions State a Aux Water Level Satisfied State B K32 Close Air Pressure Switch Satisfied State DK51 Close Burner ON, Boiler Heating to generate steam State E NEW Style Controls Boiler Sequence of OperationInitial Fill and Preheat HL-LED N14, N16, N17 go out N9, N10, N11, N12, N13 go out Boiler Blowdown/drain Water Refill After Initial Fill VHX Series Steamer Electrical Operation Cooking Compartment Controls This page Intentionally Left Blank Models Built After 5/25/00 New Style Boiler Controls Schematics VHX 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