Vulcan-Hart MHB24G, VHX24G5 manual Boiler blowdown solenoid valve clogged and not fully closing

Page 64

VHX SERIES STEAMER - TROUBLESHOOTING

SYMPTOM		POSSIBLE CAUSES

Boiler Slow to Pressurize	1.	Low water supply pressure, inline water strainer clogged or fill
(over 15 min. to achieve operating		solenoid valve malfunction. See "INLINE WATER STRAINER
pressure)		CLEANING" and "FILL AND COLD WATER SOLENOID
		VALVES" in "SERVICE PROCEDURES AND
		ADJUSTMENTS".
	2.	Boiler blowdown solenoid valve clogged and not fully closing.
		Check for a slow leak out of steamer drain. If not able to verify,
		then proceed to step 3. If blowdown solenoid valve appears to
		be functioning properly, then proceed to step 4.
	3.	Turn power switch OFF, disconnect lead wires from blowdown
		solenoid and remove it for inspection.
	4.	A heavy build-up of scalants has coated the interior of the
		boiler, creating an insulating effect. Examine interior of boiler
		as outlined under “BOILER” in "SERVICE PROCEDURES AND
		ADJUSTMENTS".
	5.	Low incoming gas pressure is reducing BTU output.
		A. Verify gas supply line to the steamer is a minimum of one
		inch diameter (ID).
		B. Check incoming line and manifold gas pressures as
		outlined in "GAS MANIFOLD PRESSURE ADJUSTMENT"
		under "SERVICE PROCEDURES AND ADJUSTMENTS".
	6.	Gas valve malfunction.
		A. Check incoming line and manifold gas pressures as
		outlined in "GAS MANIFOLD PRESSURE ADJUSTMENT
		under "SERVICE PROCEDURES AND ADJUSTMENTS".

Boiler will not heat or build pressure.	1.	Gas not on.
	2.	Power/reset switch assembly malfunction.
	3.	Boiler not filling - check fill solenoid for power, clogging or
		malfunction.
	4.	Gas pilot and/or gas manifold pressure low. See "GAS PILOT
		PRESSURE ADJUSTMENT" and "GAS MANIFOLD
		PRESSURE ADJUSTMENT" in "SERVICE PROCEDURES
		AND ADJUSTMENTS".
	5.	Cycling pressure switch open or set too high. Steamer is
		cycling on high limit.
	6.	High limit pressure switch open and not re-setting
		(malfunction).
	7.	Water too "pure" for probes to properly conduct electricity.
		NOTE: Items 8 & 9 see "WATER LEVEL CONTROLS TEST"
		in "SERVICE PROCEDURES AND ADJUSTMENTS".
	8.	Water Level Control malfunction.
	9.	Aux. Water Level Control malfunction.

Pressure relief valve(s) opening or	1.	Pressure overshoot on initial startup or long burner on times
leaking.		under heavy usage.
	2.	Pressure relief valve malfunction.
	3.	Cycling pressure switch set to high.
	4.	High limit pressure switch not set correctly or malfunctioning.

F24700 (October 2001)		Page 64 of 68

Image 64

Contents VHX Boiler Base Series High Efficiency GAS Steamers VHX24G ShownTable of Contents VHX Series Steamers Maintenance Cleaning Introduction InstallationGeneral Boiler Control Styles Water Conditioning Specifications SystemWater Supply ElectricalTools Gas SupplyStandard SpecialSteamer Operation Cabinet Base BoilerCooking Compartment Controls VHX Series Steamers OperationBoiler Blowdown Steamer Shut OFF Component Function VHX Series Steamers Component FunctionBlowdown/Drain Ignition Control ModuleSteam Header Assembly Water LevelWater Inlet Valve manual Pressure Relief ValveCompartment Pressure Switch Steam Solenoid ValveManifold Pressure Gauge Steam Supply ManifoldRemoval and Replacement of Parts VHX Series Steamers 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 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 HandleService Procedures and Adjustments Clean-OutBoiler 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 Intake Shut-Off Valve Adjustment Steam Flow Door Sealing AdjustmentCooking Compartment 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 LegendBoiler Operational Status LED Indicator Reset Engaged State CInitial Conditions State a Aux Water Level Satisfied State BAir Pressure Switch Satisfied State D K32 CloseK51 Close Burner ON, Boiler Heating to generate steam State ESequence of Operation NEW Style Controls BoilerInitial Fill and Preheat 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