Vulcan-Hart VHX24G5, MHB24G manual Cooking Compartment Controls

VHX SERIES STEAMER - ELECTRICAL OPERATION

upper and lower set point limits. The cycling pressure switch continues to energize and de-energize the heating circuit to cycle the burner ON and OFF.

This sequence continues until one of the following occurs:

1)Power switch is turned OFF.

2)Boiler water level drops below the LLCO probes for the main water level control and the auxiliary low level cut- off control

3)Boiler pressurizes to 15 PSI, causing the high limit pressure switch to OPEN.

Water Refill (After Initial Fill)

1.Water level drops below low level probe (LL).

A.HL relay is energized.

1)HL N.O. contacts CLOSE, fill solenoid is energized and HL LED comes ON.

2.Water reaches LL (low level) probe.

3.Water reaches high level probe.

A.HL relay is de-energized.

1)HL N.O. contacts OPEN, fill solenoid is de-energized and HL LED goes out.

4.The water refill cycle will occur whenever the water level is below the low level probe and will not affect the operation of either the preheat or cook cycle.

Boiler Blowdown/Drain

1.Power switch turned OFF.

A.Boiler blowdown sequence starts.

B.The automatic blowdown solenoid valve (N.O.) is de-energized and valve OPENS to drain the boiler.

C.Power is removed from all components except cold water condenser (CWC) thermostat and solenoid valve. The CWC thermostat cycles as necessary to lower the discharge temperature of the water and condense steam going into the drain.

COOKING COMPARTMENT CONTROLS

1.Conditions.

A.Doors shut (closes the N.O. door switch contacts).

B.Cooking timers OFF.

C.Compartment pressure switch contacts OPEN.

2.With boiler at operating pressure.

A.Cooking compartment pressure switch CLOSES (approx. 3 PSI).

1)Cooking compartment ready light (green) comes ON.

3.Start a cook cycle.

A.Insert product into steamer and close door.

B.Set a cook time.

NOTE: On initial startup, if a cooking timer is set immediately after the ready light comes on, steam solenoid chattering will be heard (oil canning) and the ready lights will flash for several seconds. This condition is caused by the manifold steam pressure being on the "fringe" of the pressure switch set point. When a cook timer is set, the compartment steam solenoid valve opens causing the manifold steam pressure to drop, slightly below the pressure switch set point. At the same time, steam pressure is still increasing in the boiler. This opposing condition causes a pressure "bounce" to occur. After the steam pressure passes approximately 4 psi this condition subsides. During normal operation, this condition will not be seen.

C.Contacts 1/3 of cook timer CLOSE and timer motor is energized.

1)Compartment steam solenoid valve energized and steam begins to enter the compartment.

2)Ready light (green) goes out and Cooking light (red) comes ON.

NOTE: Steam should not be seen entering either compartment until a cook time is set. This energizes the steam solenoid valve of the cooking compartment to allow steam flow.

4.Time expires on timer.

A.Timer contacts 1/3 OPEN, timer motor de- energized.

B.Steam solenoid valve de-energizes, stopping the flow steam into compartment.

C.Timer contacts 4/1 CLOSE and energize buzzer until manually turned OFF.

D.Cooking light (red) goes out and Ready light (green) comes ON.

5.Timer manually turned OFF.

A.Contacts 1/4 OPEN

B.Alarm Buzzer de-energized and stops buzzing.

6.Steamer reverts to preheat cycle until time is dialed on timer and the door is shut, water level drops below low level cut-off probe or the power switch is turned OFF.

F24700 (October 2001) Page 50 of 68