Operating instructions

3
IMPORTANT SAFETY INSTRUCTIONS
PLEASE READ THE FOLLOWING SAFETY INSTRUCTIONS CAREFULLY
This manual is designed to assist engineers who have been on
a recognised product familiarisation and training course run by
Merrychef. It has been prepared to offer technical guidance for the
402s range of Ovens.
Please remember that it is wiser not to attempt a service task if you
are unsure of being able to complete it competently, quickly, and
above all safely.
To avoid injury to yourself, and to protect the appliance from possible
damage, please follow this Safety Code when servicing these ovens.
Before attempting to repair the oven, check it for microwave emission
using a calibrated emission detector.
Check that the oven is not emitting microwaves, even when
supposedly not in operation.
Check that the oven is not operating continuously, whether the
display indicates cooking or not.
Always discharge the HT capacitors before working on the oven
using a suitably insulated 10 MW Resistor.
When testing the oven with covers off run for short periods of time
only or magnetrons will overheat and the display will show Error
condition.
Before removing any covers from the oven, do all of the following.
Switch off the mains supply and remove the plug from the wall
socket.
or
If the oven is hard wired, ensure that the power is turned off at the
isolator switch.
Note:
The On/Off switch on the oven is not adequate protection against
electric shock, as it does not isolate all of the internal wiring from the
mains.
Upon completion of a service the oven, or before reconnecting the
appliance to the electrical supply for testing, check all of the following
points:
All internal electrical connections are correct (see wiring •
diagram).
All wiring insulation is correct and is not touching a sharp •
edge.
All grounding connections are electrically and •
mechanically secure.
All door safety interlocks are secure and mechanically •
sound.
The door operation is smooth, and the arms run freely in •
the slots.
The door activates all four of the door interlock switches •
and in the correct order
The temperature sensor is correctly connected to the •
Power PCB.
Before nishing a service call, recheck the following points:
All of the electronics are functioning correctly and all of the •
touch pads are working.
Microwave emissions are below permissible limit of 5 mW/•
cm².
The power output of the oven is checked in accordance •
with the procedure page.
Oven has correct 50mm (2 inches) air gap all round and •
50mm (2 inches) above.
Air ow should not be restricted.