Southbend Marathoner - Manual (Page 42)

T
ROUBLESHOOTING M ARATHONER G OLD & S ILVER S TAR G AS C ONVECTION O VENS
TROUBLESHOOTING GUIDE
The left column of the following table lists symptoms that indicate a problem, while the center and right
columns list the possible causes and appropriate corrective action. Note that the recommendations of this
table assume that the wiring connections are good. When checking a component, always check the wiring
attached to the component as well.
Symptom Possible Cause Check or Replace
Temperature probe not working. Resistance across temperature probe leads at room temperature (70°F)
should be approximately 1096 ohms.
Temperature control not calling for heat. When heat is required, there should be continuity between terminals 6
and 7 on temperature control.
Undersized gas supply line Oven requires 3/4" ID gas line.
Low gas pressure. Oven requires 7" manifold water column pressure for natural gas, 11" for
propane.
Oven will not hold
correct temperature.
Inadequate or improper ventilation. Check ventilation hood. Verify draw and make up air adjustment.
40. Out of calibration. Calibrate according to procedure described on page
Hot surface ignitor
glows red but burners
do not come on when
thermostat calls for heat
(cooking light is on).
No power to gas valve. Check for 24V from ignition box to gas valve.
Faulty main gas solenoid. Replace gas valve.
Faulty ignition module. Replace ignition module.
Manual shutoff valve closed. Open all shut-off valve.
Manual valve on gas valve turned off. Open manual valve on gas valve.
Hot surface ignitor not in front of rear end
of burner.
Re-position hot surface ignitor to be in front of rear end of burner.
Hot surface ignitor does
not glow red.
No power to ignitor. Check that voltage from ignitor module to ignitor is 24V. Ignitor draws
approximately 3.35 amps at start as it heats up resistance goes down.
Gas valve opens approximately 1.8 amps.
Ignitor broken or cracked. Should read continuity between leads on ignitor.
No power or ignition module. Should be 24V from transformer to ignition module.
Check power to transformer. Should be voltage stamped on serial plate. Check between 3 and 6 on
terminal strip.
Check blower motor. Motor should turn
when power switch is turned on and
temperature control calls for heat.
Motor has centrifugal switch. Motor must be turning before ignition circuit
is energized. Power for motors come through contactors. Check
contactors (one for high speed, one for low speed).
Temperature control does not call for
heat.
Must read continuity between 6 and 7 on temperature control when
calling for heat.
No power out of power switch. Check that unit power cord is plugged into power supply. Check switch
for continuity when switch is closed.
TROUBLESHOOTING
First burner next to
ignitor lights, but flame
will not carry across to
other burners.
Burners not aligned. Check burner carry over wings for proper mating.
Burner and orifice out of alignment. Orifice must inject gas down center of burner.
Gas pressure to low. Oven requires 7" manifold water column pressure for natural gas, 11" for
propane.
Burner orifices clogged. Make sure burner orifices are clear.
Table continues on next page.
P AGE 42 O PERATOR ’ S M ANUAL 1181887 REV 3