Vulcan-Hart 126172, Service Manual

ELECTRIC COMBI OVEN - ELECTRICAL OPERATION

Page 43 of  68

On 20 level machines (half and full size) the heating
mode regulation is the same but with these
additional points to remember:

Top and bottom heating elements operate
independently and correspond to the top and
bottom cavity temperature probes.

Display always shows the lowest temperature.

If the cavity temperature exceeds the set point
temperature, the heating elements will not turn
on until both cavity temperature probes sense a
temperature below the set point.

Steam Pre-Heat

When the oven is turned on and the heating mode
(convection or combi) is selected, the steam
generator fills with water until the proper level is
reached. On the programable oven control, press
the Start/Stop key to begin oven heating. On the
standard and deluxe manual controls, the water pre-
heat begins after the heat selector knob is turned to
either convection or combi mode. On initial start up
only, after the cavity temperature reaches 1.8°F
below set point temperature (convection = 1/4
power) the steam generator pre-heat begins. The
steam generator heating elements then turn on for a
total time of 1.5 minutes on 6 and 10 levels and 2.5
minutes on 20 level ovens, if they are on at full
power only. When the convection heating elements
turn back on (at half power) to maintain cavity set
point temperature, the steam generator heating
elements will also turn on (at half power), for a pre-
heat time value that is automatically calculated. No
additional heating of the steam generator takes
place until either a steam or combi mode selection
is made.

Steam Regulation

Before cooking in steam mode, it is recommended
that the oven be pre-heated in convection mode at
200°F to bring the oven cavity up to temperature for
immediate steam cooking.

Steam Mode - When the oven is turned on and
the steam mode is selected, the steam
generator fills with water until the proper level
is reached. On the programable oven control,
press the Start/Stop key to begin steam
generator heating. The steam generator
heating elements turn on (always at full power)
until the actual set point temperature is reached
then turn off. If the steam mode is selected
after convection or combi mode heating, the
steam generator pre-heat is complete and the
oven is ready for steam mode cooking.

At this time, if the cavity temperature is lower than
the set point, the steam generator heating elements
turn back on until reaching the actual set point
temperature then turn off. If the cavity temperature
is higher than the set point, the steam generator
heating elements remain off and the oven will go
into cool down mode until reaching the set point
temperature. When the cavity temperature falls 1°F
or more below set point temperature, the heating
elements turn on until the cavity returns to the
actual set point temperature then turn off.

Combi Mode - On the programable and deluxe
manual controls, the steam generator heating
elements operate on a portion of the
convection bake time to provide the oven with
steam heat. The amount of steam introduced
depends on the combi steam factor setting (1-6
LED’s lit) on the control. The default steam
factor setting is 5 (1 LED lit). On the standard
manual control, a fixed steam factor of 20 is
used. When the steam generator elements are
on at full power, the convection elements are
off. If the convection heating elements are on
at half power, the steam generator heat
elements can also be on at half power. The
toggling of the heating element power allows
the current draw of the oven to remain at lower
levels. If the oven set point temperature is less
than the steam temperature setting (195°F to
212°F), the steam factor is limited to 10
regardless of the number of LED’s lit.

NOTE: The steam temperature setting (boiling point
adjustment) for elevation is pre-selected in the
configuration mode.

Indicator Lights

 (on front panel)

Steam

 Factor

Seconds

 ON

Seconds

OFF

1

5

5

85

10

5

70

2

 20

5

55

30

5

40

40

5

25

50

5

10

NOTES: 1. Default on Programmable and Deluxe manual controls.

              2. Default on Standard manual control and is non-             
                  adjustable.