Vulcan-Hart MHB24G, VHX24G5 manual Water Refill After Initial Fill, Boiler Blowdown/drain

VHX SERIES STEAMER - ELECTRICAL OPERATION

		upper and lower set point limits. The			B.	Boiler connected to correct voltage
		cycling pressure switch continues to				(120VAC).
		energize and de-energize the heating				1) Power to cooking compartment
		circuit to cycle the burner ON and OFF.
						controls. See "COOKING
		This sequence continues until one of the
						COMPARTMENT CONTROLS" later
		following occurs:				in this section.
		1) Power switch is turned OFF.			C.	Boiler properly grounded (boiler and water
		2) Boiler water level drops below the				level controls share a common ground)
		LLCO probes for the main water level			D.	Gas and water supply valve(s) ON.
		control (WLC) and the auxiliary low			E.	Main gas valve ON.
		level control.
					F.	Cycling pressure switch CLOSED.
		3) Boiler pressurizes to 15 PSI, causing
		the high limit pressure switch to open.			G.	High limit pressure switch CLOSED.
Water Refill (After Initial Fill)					H.	Cold water condenser (CWC) thermostat
1.	Water level drops below low level probe (LL).					OPEN.
					I.	Automatic blowdown valve (A.B.D.) OPEN
	A.	HL relay is energized.
						and boiler empty.
		1) HL-3 (N.O.) contacts close.		2. Turn power switch ON.
		2) Fill solenoid is energized.			A.	Relay R4 energized and R4 contacts
		3) HL LED comes ON.				(N.O.) CLOSE.
2. Water reaches LL (low level) probe.					B.	Power ON light (red) comes ON.
3. Water reaches high level probe.					C.	Blowdown solenoid valve is energized and
	A.	HL relay is de-energized.				CLOSES.
					D.	Auxiliary water level control is powered.
		1) HL-3 (N.O.) contacts open.
						1) Aux. LLCO N.O. contacts remain
		2) Fill solenoid is de-energized.
						OPEN (Aux. LLCO relay de-
		3) HL LED goes out.				energized).
4. The water refill cycle will occur whenever the					E.	Low water level light (amber) comes ON.
	water level is below the low level probe and will				NOTE: The low water indicator light will remain
	not affect the operation of either the preheat or
					ON and the safety circuit de-energized until the
	cook cycle.
					water level in the boiler reaches the auxiliary
Boiler Blowdown/drain					low level cut-off probes (aux. LLCO, minimum
1.	Power switch turned OFF.				level) for the aux. water level control, and the
					manual reset switch is pressed.
	A.	Automatic blowdown solenoid valve (N.O.)			F.	High pressure light (amber) comes ON.
		is de-energized and valve opens to drain
					NOTE: The high pressure indicator light will
		the boiler.
	B.	Power is removed from all components			remain ON and the safety circuit de-energized
					until the manual reset button is pressed (high
		except cold water condenser (CWC)
					limit pressure switch must be closed).
		thermostat and solenoid valve. The CWC
					G.	Power is connected through the high limit
		thermostat cycles as necessary to lower
		the discharge temperature of the water				pressure switch contacts (N.C.) to one side
		and condense steam going into the drain.				of the push button reset switch.
OLD STYLE CONTROLS - BOILER					H.	Water level control is powered (Low Level
This sequence of operation is written for boiler						Cut-off & Differential Control).
						1) High level (HL) relay is energized, HL
bases with the old style boiler controls. See
"BOILER CONTROL STYLES" under "GENERAL".						contacts (N.O.) CLOSE
Refer to schematic diagram 5480.						a.	HL LED lights up.
Initial Fill And Preheat						b.	Fill solenoid is energized and
1.	Conditions.						water begins filling boiler (fill
	A.	Power switch OFF.					time 4-11 min.).
F24700 (October 2001)			Page 48 of	68