Page 60 Part # MCOSM06 Rev 1 (11/03/08)
CONTROLLER OPERATIONAL TESTS
For the Garland (US Range) 200(20) – 300(30) – 410(41)
– 450(45) – 455(45+) – 470 – 4712 – 475 FAST convection oven
controls.

200 Series Controller (Thermostat only)

Turn the oven on, the oven should heat to set temperature
within 30 minutes. If the oven does not heat, ohm out the
probe, at room temperature the probe should read about
1,000 ohms. Ohm the probe at the faston connection. See
the chart for other resistance readings. If the probe reads
an open or short, replace the defective probe. Check the
probe interconnect harness to make sure the circuit is good,
connections etc.
The heat relay K1 should be energized when heating the oven
and opened if it is not calling for heat.
The fan is not controlled by the controller.

300 Series Controller

(Thermostat and relay board)

Turn the oven on, the oven should heat to set temperature
within 30 minutes. If the oven does not heat, ohm out the
probe, at room temperature the probe should read about
1,000 ohms. Ohm the probe at the faston connection. See
chart for other resistance readings. If the probe reads an
open or short replace the defective probe. Check the probe
interconnect harness to make sure the circuit is good,
connections, etc.
The heat demand rely K1B should be energized then heating
the oven and opened if it is not calling for heat. Look at the
heat LED CR1 on the relay board, the LED will be lit when the
controller calls for heat. Check the door switch if the heat
does not activate. Upper door switch is for HEAT.
The fan can switch from low to high speed. Look at the fan
LED on the relay board (there is a low CR4 and a high fan
CR30, the LED will be lit when the controller calls for either
fan. If the operator cannot switch from one fan speed to
another check the keypad. If the light switched on the display
from one fan speed to another but the fan did not change
speeds check the relay board. If the display switched and the
fan went o, check the fan itself.
If the keypad does not respond, check the keypad as outlined
in bulletin B-107-2001.
If the potentiometer does not adjust the temperature, check
the potentiometer. Pot is a 0 to 10.25K Ohm pot.

410 Series Controller

(Thermostat, display and relay board)
Turn the oven on, the oven should heat to set temperature
within 30 minutes. Press the temperature icon and the
temperature can be viewed above 100 degrees F. If the oven
does not heat, ohm out the probe, at room temperature the
probe should read about 1,000 ohms. Ohm the probe at the
faston connection. See chart under Probes in section four for
other resistance readings. If the probe reads an open or short
replace the defective probe.
The heat demand relay K1F should be energized when
heating the oven and opened if it is not calling for heat.
Look at the heat LED CR1 on the relay board, the LED will be
lit when the controller calls for heat. Check the upper door
switch if the heat does not activate.
The fan can switch from low to high speed. Look at the fan
LED on the relay board (CR3 LED for high and CR4 for low
speed), the LED will be lit when the controller calls for either
fan. If the operator cannot switch from one fan speed to
another, check the keypad. If the light switched on the display
from one fan speed to another but the fan did not change
speeds check the relay board. If the display switched and the
fan went o, check the fan itself.
If the keypad does not respond, check the keypad as outlined
in bulletin B-107-2001 If the encoder does not adjust the
temperature, check from idle; press the set function key and
adjust the encoder; the display should change accordingly. If
it does not, change the encoder.

450 Series Controller

(Thermostat, display and relay board)
Follow the steps for the 410 controller.
If the display shows a temperature only and the function keys
do not operate, check to see if the hold LED is active. Press
cancel to deactivate the hold feature and return to the idle
mode.

455 Series Controller

(Thermostat, display and relay board)
Follow the steps for the 410 controller.
If the display shows a temperature only and the function keys
do not operate, check to see if the hold or core temp LED is
active. Press cancel to deactivate the hold feature and return
to the idle mode or remove the core probe to return to idle
mode.