Part # MCOSM06 Rev 1 (11/03/08) Page 65
Problem Possible Cause Corrective Action
Burners and fan stay
on when door is open
past 30° opening
A. Loose wire from upper door switch A. Check connections at door switch and relay
board
B. Shorted upper door switch B. Replace upper door switch
Fan runs for a period of
time, shuts down then
comes back on after
several minutes
A. Motor has tripped on internal
overload
A. Check for a minimum 6" clearance at rear of the
unit to a wall or heat source
B. Check air intake vents on back of motor for
obstructions
C. If problem persists and above have been
corrected replace motor assy
Timer slow counting
down
A. Timer is in hours/min A. Refer to operations manual or bulletin
#B-19-2001 on how to change from hour/min to
min/sec
Temperature out of
calibration
A. 400 series controllers A. Conrm oven cavity temp with resistance
change. If out more than 20 OHMs replace probe
B. 200 & 300 series controllers B. Calibration can be performed by repositioning
temperature dial. See Temperature calibration in
manual
C. Potentiometer defective C. Check for proper 'sweep' on potentiometer 0.0 to
10.25 KOHMS