11
R-90GCH
MAGNETRON TEMPERATURE FUSE TF
The temperature fuse located on the waveguide flange is
designed to prevent damage to the magnetron if an over
heated condition develops in the magnetron due to cooling
fan failure, obstructed air guide, dirty or blocked air intake,
etc. Under normal operation, the temperature fuse remains
closed. However, when abnormally high temperatures are
reached within the magnetron, the temperature fuse will
open at 150˚C causing the oven to shut down.
TOP HEATER THERMAL CUT-OUT TC1
The thermal cut-out located on the thermal cover upper is
designed to prevent damage to the top heating element
unit if an over heated condition develops in the top heating
element unit due to convection fan failure, thermistor
failure, obstructed air ducts, dirty or blocked air intake, etc.
Under normal operation, the thermal cut-out remains
closed. However, when abnormally high temperature are
reached within the top heating element unit, the thermal
cut-out will open at 170˚C causing the oven to shut down.
When the thermal cut-out has cooled, the thermal cut-out
closes at 155˚C.
SIDE HEATER THERMAL CUT-OUT TC2
The thermal cut-out located on the thermal cover left is
designed to prevent damage to the side heating element
unit if an over heated condition develops in the top heating
element unit due to convection fan failure, thermistor
failure, obstructed air ducts, dirty or blocked air intake, etc.
Under normal operation, the thermal cut-out remains
closed. However, when abnormally high temperature are
reached within the side heating element unit, the thermal
cut-out will open at 150˚C causing the oven to shut down.
When the thermal cut-out has cooled, the thermal cut-out
closes at 130˚C.
TOP HEATING ELEMENT H1
The top heating element is located at the top of the oven
cavity. It is intended to heat air driven by the convection
fan. The heated air is kept in the oven and force-circulated
and reheated by the top heating element.
SIDE HEATING ELEMENT H2
The side heating element is located at the left side of the
oven cavity. It is intended to heat air driven by the convec-
tion fan. The heated air is kept in the oven and force-
circulated and reheated by the top heating element.
TURNTABLE MOTOR TTM
The turntable motor rotates the turntable located in the
bottom of the oven cavity, so that the food on the turntable
is cooked evenly during cooking. The turntable may turn in
either direction.
FAN MOTOR (MAGNETRON SIDE) FM
The fan motor drives a blade which draws external cool air.
This cool air is directed through the air vents surrounding
the magnetron and cools the magnetron. This air is chan-
nelled through the oven cavity to remove steam and
vapors given off from the heating foods. It is then ex-
hausted through the exhausting air vents at the oven
cavity.
FAN MOTOR (HIGH VOLTAGE TRANSFORMER
SIDE) FM
The fan motor drives a blade which draws external cool air.
This cool air is directed through the air vents surrounding
the power transformer and cools the power transformer.
This air is channelled through the oven cavity to remove
steam and vapors given off from the heating foods. It is
then exhausted through the exhausting air vents at the
oven cavity.
CONVECTION COOKING SYSTEM
This oven is designed with a hot air heating system where
food is not directly heated by the heating element, but is
heated by forced circulation of the hot air produced by the
heating elements. The air heated by the heating elements is
circulated through the convection passage provided on the
outer casing of the oven cavity by means of the convection
fan which is driven by the convection motor CM. It then
enters the inside of the oven through the vent holes provided
on the top and left sides of the oven. Next, the hot air heats
the food on the turntable and leaves the oven cavity through
the vent in the center of the oven cavity back side wall.
Without leaving the oven, this hot air is reheated by the
heating elements, passes through the convection passage
and enters the inside of the oven cavity again, in a continuing
cycle. In this way, the hot air circulates inside the oven cavity
to raise its temperature and, at the same time, comes into
contact with the food being cooked. When the temperature
inside the oven cavity reaches the selected temperature, the
heating elements are de-energized. When the temperature
inside the oven cavity drops below the selected tempera-
ture, the heating elements are energized again. In this way,
the inside of the oven cavity is maintained at approximately
the selected temperature. When the convection time reaches
0, the heating elements are de-energized and the convec-
tion fan stops operating and the oven shuts off.
Flow of hot air:
The rotation direction of the convection motor CM is
controlled by relay RY6. When the convection fan rotates
clockwise, the hot air from the oven cavity left side wall
blows stronger than one from the oven cavity top wall. (
This mode is called “Convection mode”.) When the con-
vection fan rotates counterclockwise, the hot air from the
oven cavity top wall blows stronger than one from the oven
cavity left side wall. (This mode is called “JET mode”.)
Figure D-2. Rotation direction of convection fan
Side heating
element unit
Top heating
element unit
Convection
fan
Convection mode
JET
mode
FRONT VIEW
