Garland MCO-GD-10M, Service Manual

Page: 9 / 28

9
ELECTRONIC CONTROL FAILURE CODES
The GARLAND digital control has a self-diagnostic program. If a problem occurs within the digital controller, you may
see one of the "F" codes.
Below is a listing of the "F" codes with explanations:
-F1-
Relay output is enabled when not cooking. If this failure code appears in the display, the cook relay may be on
even if the control is not cooking. The control should be replaced.
-F2-
Over temperature alarm. If this failure code appears in the display the control is sensing an oven temperature
50° or more above the maximum set temperature (500°). This failure may be caused by a faulty sensor.
Check the sensor connection for loose wires.
Replace the sensor and check for proper operation.
If failure continues replace the control.
-F3-
Open sensor circuit. If this failure appears in the display, the control is sensing an open circuit at the sensor
input. This failure is most often caused by a poor connection or broken sensor.
Check sensor connection and leads for broken wires of loose connections. Replace sensor and check for
proper operation. If failure continues replace control.
-F4-
Shorted sensor circuit. If this failure appears in the display, the control is sensing a short circuit at the sensor
input. This failure is most often caused by loose wires at the connection of shorted sensor leads.
Check sensor connection and leads for loose wires. Replace sensor and check for proper operation. If failure
continues replace control.
-F5-
Relay outputs not enabled when cooking. If this failure appears in the display the control cannot turn the
relays on even when cooking. The control should be replaced.
-F6-
No 60 Hz input. The control does not sense the input power. This failure mode is most often the result of a
failed component in the control. However, this failure may also be the result of a very noisy power line. Look
for any large electrical noise producing machinery (such as mixers, compressors, dishwashers etc.). If
possible, turn these machines off. Reapply power to the oven. If the failure repeats, replace the control. If
the failure does not repeat, an electronic control may not work in this application because of noise. You must
isolate the supply circuit.
-F7- The control has detected that calculated EEPROM check sum is not the same as the expected check sum
retrieved from the EEPROM. When the control detects this error code, it will disable outputs before the alarm
sounds.
RESISTANCE vs. TEMPERATURE CHART FOR INTERNAL OVEN TEMPERATURE SENSOR
The chart below will provide the Ohms at various temperatures. This will enable you to determine if the temperature
probe is operable.
The chart is in Degrees Fahrenheit. How to use chart, for 350
°
, read down to 300 then across to 50, answer is
1654Ohms of resistance.
TEMP 0° 10° 20° 30° 40° 50° 60° 70° 80° 90°
0°
932 953 974 995 1016 1038 1059 1080 1101 1122
100° 1143 1163 1184 1205 1226 1247 1267 1288 1309 1329
200°
1350 1370 1391 1411 1432 1452 1472 1493 1513 1533
300°
1553 1574 1594 1614 1634 1654 1674 1694 1714 1733
400° 1753 1773 1793 1813 1832 1852 1871 1981 1911 1930
500°
1949 1969 1988 2008 2027 2046 2065 2085 2104 2123
ROBERTSHAW COM6000 CONTROLLER