Viking Professional VHSO205SS, Руководство по обслуживанию

Страница: 13 / 52

13
VHSO205SS
Monitor switch
Latch hook left
Door handle
Latch
head
Secondary
interlock switch
Door
sensing switch
Latch hook right
Latch
head
3. If the door is opened, and the primary interlock relay
and secondary interlock switch contacts fail to open, the
monitor fuse blows simultaneously with closing of the
monitor switch contacts.
CAUTION: BEFORE REPLACING A BLOWN MONITOR
FUSE TEST THE DOOR SENSING SWITCH,
PRIMARY INTERLOCK RELAY, SECOND-
ARY INTERLOCK SWITCH AND MONITOR
SWITCH FOR PROPER OPERATION. (REFER
TO CHAPTER “TEST PROCEDURE”).
NOTE: MONITOR FUSE AND MONITOR SWITCH ARE
REPLACED AS AN ASSEMBLY.
THERMISTOR
The thermistor is a negative temperature coefficient type.
The temperature in the oven cavity is detected through the
resistance of the thermistor, and then the control unit causes
the heater relay to operate, thus the current to the heating
elements is turned ON/OFF. If the convection cooking or some
cooking modes which use the top / side heating elements
is started and the oven temperature does not rise above
100
ο
F (37.8
ο
C), the control unit will stop the oven after 10
minutes. In this case, the thermistor may be opened.
MAGNETRON TEMPERATURE FUSE.
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
remain open at 30
ο
F(150
ο
C) causing the oven to shut
down.
TOP HEATER THERMAL CUT-OUT
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 338
ο
F (170
ο
C) causing the oven to shut down.
When the thermal cut-out has cooled, the thermal cut-out
closes at 311
ο
F(155
ο
C).
SIDE HEATER THERMAL CUT-OUT
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
The door is opened by pulling the door handle down and
forward, referring to the figure D-1. When the door handle is
pulled down, the latch heads are moved upward. And then
when the door handle is pulled forward, the latch heads
are released from the latch hooks right and left. Now, the
door will open.
Figure D-1. Door Open Mechanism
DOOR SENSING AND SECONDARY INTERLOCK
SWITCHES
The door sensing switch in the primary interlock system is
mounted in the lower position on the latch hook right, the
secondary interlock switch is mounted in the lower position
on the latch hook left. They are activated by the latch heads
on the door. When the door is opened, the switches interrupt
the circuit to all components except for the oven lamp. A
cook cycle cannot take place until the door is firmly closed
thereby activating both interlock switches. The primary inter-
lock system consists of the door sensing switch and primary
interlock relay located on the control circuit board.
MONITOR SWITCH
The monitor switch is mounted on the upper position of latch
hook left. It is activated (the contacts opened) by the left
latch head while the door is closed. The switch is intended
to render the oven inoperative by means of blowing the
monitor fuse when the contacts of the primary interlock
relay and secondary interlock switch fail to open when the
door is opened.
Functions:
1. When the door is opened, the monitor switch contact close
(to the ON condition) due to their being normally closed.
At this time the door sensing and secondary interlock
switches are in the OFF condition (contacts open) due
to their being normally open contact switches.
. As the door goes to a closed position, the monitor switch
contacts are first opened and then the door sensing
switch and the secondary interlock switch contacts close.
(On opening the door, each of these switches operate
inversely.)
DESCRIPTION AND FUNCTION OF COMPONENTS
DOOR OPEN MECHANISM