Vulcan-Hart MHB24G, VHX24G5 manual VHX Series Steamers Component Function, Blowdown/Drain

VHX SERIES STEAMERS - COMPONENT FUNCTION

COMPONENT FUNCTION

CABINET BASE BOILER CONTROLS

Power Switch (ON/OFF) . . . . . . . . .

Reset Switch (Manual) . . . . . . . . . .

Boiler Fill Solenoid Valve . . . . . . . .

Cold Water Condenser

Solenoid Valve . . . . . . . . . . . . . . . . .

Blowdown/Drain

Solenoid Valve . . . . . . . . . . . . . . . . .

Cycling Pressure Switch . . . . . . . . .

High Limit Pressure Switch . . . . . .

Main Water Level Control . . . . . . . .

Auxiliary Water Level Control . . . . .

Transformer . . . . . . . . . . . . . . . . . . .

Ignition Control Module . . . . . . . . .

Main Gas Valve . . . . . . . . . . . . . . . .

Pilot Gas Valve . . . . . . . . . . . . . . . .

Combustion Blower . . . . . . . . . . . .

When turned ON, supplies power to the control circuit.

Resets the low water level safety circuit on initial startup or the occurrence of a low water condition and allows the boiler to fill with water. Also, resets the high pressure level safety circuit on initial startup or the occurrence of a high pressure condition and allows the gas ignition cycle to start.

Admits water to the boiler when demanded by the water level control to maintain the correct water level in the boiler.

Allows cold water flow into the boiler blowdown drain box to condense steam and cool the hot water before its discharge into the drain.

A normally open valve (N.O.) that closes to allow boiler to fill and pressurize when power switch is turned ON and opens when power switch is turned off to blowdown and drain the boiler. This valve is plumbed into the drain line of the boiler.

Controls boiler pressure between prescribed limits by turning the heat source on and off.

Protects the boiler from pressures above 15 psi by removing power from the heating circuit. This pressure setting is higher than the cycling pressure switch in order to turn off the heat source before the boiler pressure reaches its limit. After the pressure drops below approximately 12psi, press the rest switch of the front control panel to rest the safety circuit.

A dual functioning control that allows water to fill and maintain the proper level in the boiler providing differential water level control; and shuts off the main gas valve if the water level drops too low providing low level cut-off protection. The water level control works by using three different probe lengths to monitor the water level. The probes consist of a high level (HL), low level (LL) and low water cut-off (LLCO).

A back up to the low level cut-off on the main control. Protects the boiler and heating system components from a low water cut-off condition by opening the 24VAC voltage path to the heating system circuit. Also, energizes the low water "light" on the front control panel.

Provides 24VAC power to ignition control module and heating circuit.

Controls and monitors gas heating. Energizes pilot valve coil to supply gas to pilot, generates spark to ignite gas at the pilot, monitors the presence of flame and energizes the main and pilot valve coils on the main gas valve upon a call for heat.

A gas solenoid valve that opens to allow gas flow to the main burner after the successful ignition of the pilot burner when a call for heat is made.

A gas solenoid valve that opens to allow gas flow to the pilot to ignite the main burner when a call for heat is made. The valve is energized by a time delay circuit on the relay board during ignition trial for approximately 15 seconds. New style controls only.

Provides forced air to the gas/air mixture for gas pilot and main burner combustion.

F24700 (October 2001) Page 10 of 68