Blue Seal 203926, Руководство по обслуживанию

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Revision 7/F3527
© Moffat Ltd, November 2004
3.2 EXPLANATION OF CONTROL
SYSTEM
The G32 Turbofan convection oven features
multi-function operator controls for which a
correct understanding of their operation is
required before carrying out any service or
fault repair work. The control device functions
are explained as follows:
A power switch on the control panel isolates
all to the controls of the oven. With the power
switch Off all functions of the oven are
inoperable.
With the power switch On (illuminated) power
is directly supplied to the 60 minute bake
timer, steam (water injection) switch, door
microswitch, light switch, and the temperature
control circuit. The oven circulation fan will
operate only when the thermostat is turned
on, although will continuously run when the
thermostat cycles on/off to maintain oven set
temperature. The control panel light switch
will turn the oven lights on when the door is
closed only when the light switch is held in.
The oven lights will come on automatically
when the door is open, as this is controlled by
the door microswitch.
The 60 minute timer is a mechanical timer and
can therefore be operated with the oven’s
power switch On or Off. However, only with
the oven’s power switch On will the switch
contacts of the 60 minute timer turn on the
time-up buzzer and illuminate the time-up
indicator on the control panel. The buzzer
and time-up indicator provide indication that
the time setting has run down to zero and at
this point will remain On continuously until the
60 minute timer has been manually set back
to the Off (vertical) position. The 60 minute
timer does not control any other part of the
oven’s operating system as this timer is
independent of the temperature control and
heating system.
The steam (water injection) switch on the
control panel can be operated whenever the
power switch is On. The switch is momentary
like the light switch and when depressed, will
operate the electric solenoid valve at the rear
of the oven and inject water across the oven
fan from the flat spray (vertical) nozzle
positioned at the rear of the oven. Releasing
the steam button will close the solenoid valve.
This feature is used to instantaneously add
steam into the oven.
The temperature control of this oven is with a
capillary type thermostat which can be set to a
required cooking temperature.
The thermostat switch has a separate switch
body assembled onto the front from the shaft
assembly and when the thermostat is set to a
cooking temperature, the switch contacts turn
on the oven fan. The switch is closed (fan on)
whenever the thermostat is not in the Off
(vertical) position. The control panel indicator
light above the thermostat knob cycles On
and Off with the thermostat to indicate when
the gas burners are on and the oven is
heating.
The G32 Turbofan oven has a infrared
surface combustion burner fitted in a burner
box underside the oven. The burner box is
directly ducted into the oven chamber through
a flue duct connecting to an opening behind
the oven circulation fan. The fan draws the
burner box heated air and products of
combustion directly into the oven chamber
(directly fired system) to maximise
performance. A flue exit in the top of the oven
chamber provides final flueing of the
combustion products out of the oven.
The burner being of an infrared type is
provided with primary combustion air at the
injector orifice intake at the front of the burner,
and draws in the primary air through the
venturi effect of the burner mixer tube elbow.
Additional secondary air is provided in the
burner box via an air intake on the underside
of the burner box that is intake ducted to the
air openings on the right hand side of the G32
base assembly. The addition of the
secondary air allows for complete combustion
of the gas due to the infrared burner being
under the draft conditions of the oven fan
extraction on the burner box. Accordingly, the
infrared burner will display conventional
surface combustion infrared combustion
characteristics as well as having a flame
plume drafted toward the right hand side of
the oven (toward the burner box flue duct)
when viewed from the front of the oven, after
removal of the front service panel.
The burner is automatically controlled by the
main oven thermostat or hold thermostat, via
an automatic ignition and valve control device,
which operates a gas solenoid valve to
provide gas to the burner as required to
maintain the set thermostat temperature.
NOTE: On 110 volt models the ignition