Merrychef 402s - Manual (Page 25)

402s Ovens Pt. No. 32Z3522 Issue 6
25
1. Monitor switch
The Monitor switch will produce a short circuit across the mains supply when the door
is opened if the Primary interlock switch is faulty, thus blowing the microwave fuse
and rendering the oven inoperative.
2. Primary Interlock and Secondary Interlock
The Primary switch will cut off the microwave emissions from the oven when the door
is opened by breaking the electrical supply circuit to the transformers. The Secondary
interlock switch will cut off the microwave emission if the Primary switch has failed.
Note:
If operation of the Monitor switch has caused the Microwave Fuse to blow, the
Primary and Monitor microswitches must be changed as they may have been
damaged by the high short-circuit currents involved.
The door on the 402s oven is monitored by four microswitches. Three are used in the conventional
“Primary, Secondary and Monitor” switch arrangement shown below and the fourth sends a signal
to the Logic PCB. The switches operate as follows:
PROCEDURE FOR DOOR INTERLOCK ADJUSTMENT AND TEST 1
Microswitches
RH side
Left Side
Monitor
SW1
Primary
SW2
Secondary
SW3 Door closed
Logic PCB
SW4
Right Side
Door Interlock Arrangement: Switches shown in Door Closed position
Power In
Power
Out
L 1
L 2
Secondary
switch
RHS LHS
Monitor
switch
Primary
switch
Logic
PCB