Service manual

ELECTRIC CONVEYOR OVENS - TROUBLESHOOTING
Form 24641 (MARCH 1999) Printed in U.S.A.
TROUBLESHOOTING
WARNING:
CERTAIN PROCEDURES IN THIS SECTION REQUIRE ELECTRICAL TESTS OR MEASUREMENTS
WHILE POWER IS APPLIED TO THE MACHINE. EXERCISE EXTREME CAUTION AT ALL TIMES. IF
TEST POINTS ARE NOT EASILY ACCESSIBLE, DISCONNECT POWER, ATTACH TEST EQUIPMENT AND
REAPPLY POWER TO TEST.
SYMPTOMS POSSIBLE CAUSES
Blower motor(s) and coolin
g
fans not
operatin
g
with power switch on.
1. Line volta
g
e incorrect.
2. Master switch malfunction.
3. Fuse open.
4. Solid state relay inoperative.
5. Motors inoperative.
6. Interconnectin
g
wirin
g
malfunction.
Blower motor(s) operates; all heat elements
do not operate.
1. Hi
g
h limit thermostat open.
2. Fuses open.
3. DC power supply module inoperative.
4. Temperature control malfunctionin
g
.
Low heat. 1. One or more elements not functionin
g
.
2. Fuse open.
3. Element solid state relay inoperative.
4. Interconnectin
g
wirin
g
malfunction.
Belt does not turn. 1. Direction switch in off position.
2. Chain or
g
ear malfunction.
3. Fuse open.
4. Drive motor inoperative.
5. Speed control malfunction.
Belt jumps. 1. Chain loose.
Excessive or low heat. 1. Temperature probe malfunction.
2. Temperature control inoperative.
Uneven cookin
g
. 1. Air distribution incorrect.
2. Blower motor malfunctionin
g
.
Speed display shows “OL”. 1. Belt stuck or jammed.
2. Drive motor overloaded.
Intermittent problems. 1. Hi
g
h ambient temperatures.
2. Wirin
g
connections loose.
3. Coolin
g
fan malfunction.
Cookin
g
is not even. 1. Air distribution panels need adjustment.