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,
a.Fill solenoid energized, water begins filling the boiler (fill time
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
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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