Troubleshooting; Troubleshooting Guide - Southbend Marathoner Operator's Manual

T
ROUBLESHOOTING

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
Oven will not hold Temperature probe not working.
correct temperature.
Temperature control not calling for heat.
Undersized gas supply line
Low gas pressure.
Inadequate or improper ventilation.
Out of calibration.
Hot surface ignitor No power to gas valve.
glows red but burners
Faulty main gas solenoid.
do not come on when
thermostat calls for heat
Faulty ignition module.
(cooking light is on).
Manual shutoff valve closed.
Manual valve on gas valve turned off.
Hot surface ignitor not in front of rear end
of burner.
Hot surface ignitor does No power to ignitor.
not glow red.
Ignitor broken or cracked.
No power or ignition module.
Check power to transformer.
Check blower motor. Motor should turn
when power switch is turned on and
temperature control calls for heat.
Temperature control does not call for
heat.
No power out of power switch.
First burner next to Burners not aligned.
ignitor lights, but flame
Burner and orifice out of alignment.
will not carry across to
other burners.
Gas pressure to low.
Burner orifices clogged.
Table continues on next page.
P 42
AGE
M G & S
ARATHONER OLD
Check or Replace
Resistance across temperature probe leads at room temperature (70°F)
should be approximately 1096 ohms.
When heat is required, there should be continuity between terminals 6
and 7 on temperature control.
Oven requires 3/4" ID gas line.
Oven requires 7" manifold water column pressure for natural gas, 11" for
propane.
Check ventilation hood. Verify draw and make up air adjustment.
Calibrate according to procedure described on page
Check for 24V from ignition box to gas valve.
Replace gas valve.
Replace ignition module.
Open all shut-off valve.
Open manual valve on gas valve.
Re-position hot surface ignitor to be in front of rear end of burner.
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.
Should read continuity between leads on ignitor.
Should be 24V from transformer to ignition module.
Should be voltage stamped on serial plate. Check between 3 and 6 on
terminal strip.
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).
Must read continuity between 6 and 7 on temperature control when
calling for heat.
Check that unit power cord is plugged into power supply. Check switch
for continuity when switch is closed.
Check burner carry over wings for proper mating.
Orifice must inject gas down center of burner.
Oven requires 7" manifold water column pressure for natural gas, 11" for
propane.
Make sure burner orifices are clear.
O
PERATOR
S G C
ILVER TAR AS ONVECTION
' M 1181887 3
S ANUAL REV
O
VENS
40.