Merrychef conneX 12e - Page 27

3 Technical data
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Merrychef conneX
®
service and repair manual
27
Description
Features
Function
Rating
Trouble shooting
Convection Motor.
The convection motor
is a 3-phase AC motor
that runs at variable
speeds and is powered
by a motor speed
controller (VFD). The
windings are thermally
protected (two grey
wires). The fan will
continue to run until the
oven is switched off
(Idle fan speed reduces
to 30% once cooled
down to 100
o
C.
Provides variable
percentages of airflow
that is heated into the
oven cavity used for
accelerated cooking.
This is the convection
and impingement
process.
Supply Voltage: DC
square wave frequency
that simulates 3ph
voltages up to 220V at
100%
Resistance: 7.5 10%
across windings.
Check for open circuits
or shorts to ground.
Check for locked rotor
(Power Off)
Follow VFD Drive
Trouble shooting
checks.
Convection Motor IP.
Thermal Switch within
the Convection Motor.
Two black wires.
Normally Closed,
monitors convection
fan motor internal
temperature. Opens
when the motor gets
too hot.
Breaks connection
between wires 82 & 83
for the relay coil on the
on the VFD Drive Live
supply, which in turn
stops the voltage
supply to the
convection fan motor.
Switched Voltage;
12VDC.
Resistance if open O.L.,
if closed = 0
Opens at 160
o
C (320
o
F)
Check continuity
through switch.
Check convection fan
motor IP connections
on Safety Relay.
Follow Convection
Motor Trouble
shooting checks.
Convection Fan Safety
Relay.
Controlled by the
thermal switch (IP)
within the convection
fan motor.
Switches the power
supply, wires 80 (64)
to 84, on to the VFD
(Motor Speed
Controller) when the
convection fan motor
temperature is within
normal operating
limits (IP closed circuit).
Coil Voltage;
12VDC,
Resistance 295
Switched Voltage
230VAC, Resistance if
open O.L.,
if closed = 0
Check SMPS
connections 81 & 82.
Check convection fan
motor IP continuity
and connections.
Overheat Thermostat
(Over Temp Stat /
Cavity Stat).
Manual reset, capillary
tube, normally closed,
monitors cavity
temperature. Opens
when the cavity
temperature gets too
hot.
Breaks control safety
circuit control voltage
signalling the IO Board
to de-energise heating
and microwave circuits
based on the
temperature inside
oven cavity. The oven
shuts down and
displays E104.
Switched Voltage;
12VDC.
Resistance if open O.L.,
if closed = 0.
Opens at ≈300
o
C (570
o
F)
Check continuity
through switch.
Check for 12VDC on
both sides of switch.
Terminals are normally
closed, if open, reset
thermostat and test
oven for proper
operation
Check IO X512
Check IO LEDs LD14 to
LD18.