Welbilt MERRYCHEF conneX Service & Repair Manual page 28

3 Technical data
Description Features
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 Drive).
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
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
Overheat Thermostat Manual reset, capillary
(Over Temp Stat / tube, normally closed,
Cavity Stat) monitors cavity
temperature. Opens
when the cavity
temperature gets too
hot
Magnetron Limit Stat(s) Automatic reset.
Monitors surface
temperature. Normally
Closed, opens when
the magnetron surface
temperate gets too hot
Merrychef conneX ® service and repair manual
Function
Provides variable
percentages of airflow
that is heated into the
oven cavity used for
accelerated cooking.
This is the convection
and impingement
process.
o C & below).
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.
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.
Breaks control safety
circuit control voltage
signalling the IO Board
to de-energise heating
and microwave circuits
based on the
temperature of the
magnetron case. The
oven shuts down and
displays E117, E118.
Rating Trouble shooting
Supply Voltage: DC Check for opens, shorts
square wave frequency or grounds
that simulates 3ph Check for locked rotor
voltages up to 220V at (Power Off)
100% Follow VFD Drive
Resistance: 7.5Ω ±10% Trouble shooting
across windings checks.
Switched Voltage; Check continuity
120VAC through switch.
Resistance if open O.L., Check convection fan
if closed = 0Ω motor IP connections
Opens at 160 C (320 F) on VFD. Follow
o o
Convection Motor
Trouble shooting
checks
Switched Voltage; Check continuity
12VDC. through switch.
Resistance if open O.L., Check for 12VDC on
if closed = 0Ω. both sides of switch.
Opens at 300 o C (570 o F) Terminals are normally
closed, if open, reset
thermostat and test
oven for proper
operation
Check IO X512
Check IO LEDs LD14 to
LD18
Switched Voltage; Check continuity
12VDC. through switch(es).
Resistance if open O.L., Check for 12VDC on
if closed = 0Ω. both sides of
Opens at 125 C (257 F), switch(es).
o o
automatically closes Allow magnetron to
once magnetron case cool before testing.
temperature drops to A dirty air filter is a
80 o C (177 o F) major root cause of
this failure
Check IO connections
& plugs on X513 &
X514
Check IO LEDs LD16 &
LD18
Back to contents >
28