Vulcan-Hart 126172, Service Manual

Page: 38 / 68

ELECTRIC COMBI OVEN - ELECTRICAL OPERATION
Page 38 of 68
2SOL Drain Cool
Down Solenoid Valve . . . . . . . . . .
Admits cold water to the cavity drain and mixes with the hot to condense
steam and cool the drain water before entering the floor drain. This
solenoid valve is energized whenever the steam generator heating
elements are energized. Does not operate during a drain cycle.
3SOL Water Fill
Solenoid Valve . . . . . . . . . . . . . . .
Admits water to the steam generator when requested by to oven control,
to fill or replenish the steam generator water level.
1SW Door Magnetic
Reed Switch . . . . . . . . . . . . . . . . .
Signals the oven control that door is closed and can be locked.
2SW Door Mech Switch . . . . . . . . Allows door motor to operate to unlock door.
3SW Door Mech Switch . . . . . . . . Allows door motor to operate to lock door.
5SW Door Mech Switch . . . . . . . . Allows door motor to operate to lock door (20 Level only).
6SW Door Mech Switch . . . . . . . . Allows door motor to operate to unlock door (20 Level only).
4SW Cavity Vent Switch . . . . . . . . Signals the oven control, that the vent is opened or closed.
1TAS & 2TAS
High Limit Thermostats . . . . . . . .
Removes power from board relays K6, K7, K8, K9 & K10 if oven cavity
temperature rises above 650°F. Must be reset manually.
1TF & 2TF Thermal Fuses . . . . . . Removes power from KM1, KM2, KM3 & KM6 (6 level); KM1, KM2, KM3,
KM6 & KM7 (10 level) and KM1, KM2, KM3, KM5, KM6 & KM7 (20 level
half and full) if steam generator temperature rises above 243°F.
3TF Thermal Fuse . . . . . . . . . . . . Removes power from KM1, KM2, KM3, KM5, KM6 & KM7 (20 level half
only) if steam generator temperature rises above 243°F.
4TF Thermal Fuse . . . . . . . . . . . . Removes power from KM1, KM2, KM3, KM5, KM6 & KM7 (20 level full
only) if steam generator temperature rises above 243°F.
1TB Terminal Block . . . . . . . . . . . Incoming voltage supply connection.
1T Power Supply Board
& Transformer . . . . . . . . . . . . . . .
Supplies 12VAC for cavity light; 24VAC to relay board and oven control
board; 230VAC or 90VAC to cavity fan motor(s) at full or half speed; and
230VAC to all other electrical controls except heaters.
Water Level Sensors . . . . . . . . . . Senses the water level in the steam generator and signals the oven
control to energize or de-energize the fill solenoid valve. The water fills
until the circuit between the two sensors is completed plus an additional
0.5 seconds. With the water at the proper level, if a call for heat is made
from the oven control, the steam generator heating elements turn on until
the cavity temperature is satisfied then turn off. When the water level
falls, the circuit opens and the fill cycle repeats. If the circuit remains
open longer that three seconds, the heating elements are de-energized
until the level rises to complete the circuit.
KM1 (1CON) . . . . . . . . . . . . . . . . . Contactor for half power full speed (1500 RPM) cavity fan motor(s).
When energized along with KM2, provides full power and full speed
(contactors KM1 + KM2 energized). When half power half speed mode is
selected, contactor KM1 is energized only.
KM2 (2CON) . . . . . . . . . . . . . . . . . Contactor for half power half speed (800 RPM) cavity fan motor(s). When
energized along with KM1, provides full power and full speed (contactors
KM1 + KM2 energized). When half power half speed mode is selected,
contactor KM2 is not energized.
KM3 (3CON) . . . . . . . . . . . . . . . . . Contactor for steam generator heating elements; (2HTR) on 6 level;
(2HTR) and (4HTR) on 10 level; (2HTR) and (4HTR) on 20 level half.