Heating System - Blodgett MT3255 Series Service And Repair Manual

HEATING SYSTEM

POSSIBLE CAUSE(S)
Symptom #1 --- Burner will not fire (standard controls)
Oven in off mode.
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No power to the oven.
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Fuse blown on the control panel.
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Determine if the controller setpoint is above actu-
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al.
Intermittent Ignition Device (IID) system locked
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out.
Air pressure switch may be open.
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Blower motor(s) not running.
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High limit in front panel open.
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Hi limit on Hi/Lo limit board has been hit.
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Verify that the pilot goes out when unit is shut
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down.
Verify that combustion motor is spinning and that
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the centrifugal switch is closed.
Temperature not programmed into cooking com-
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puter.
Time not programmed into cooking computer.
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Heat relay defective (computer controlled
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ovens).
Gas pressure to oven too high.
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Gas pressure to oven too low.
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TROUBLESHOOTING
SUGGESTED REMEDY
Turn the oven on.
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Determine if the circuit breaker is tripped.
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Replace the fuse.
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If the setpoint is not above the actual, reset ac-
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cordingly.
Reference Technical Appendix (page 6---1
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through 6---3).
Check convection blower for proper operation.
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Verify voltage to motor. If voltage is present, re-
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place the motor or start capacitor.
Verify that the temperature in the front panel is
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lower than 140_F (60_C).
Verify that the oven temperature exceeded 600_F
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(316_C).
If pilot does not extinguish, replace the pilot valve.
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If the motor is not spinning, check the transform-
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er and time delay relay in the control box on the
top of the combustion motor. If one or both are
bad, replace. If the motor is spinning and there
are not 24 volts to the ignition control box, the
centrifugal switch is bad. Replace the combus-
tion motor.
Program cook temperature into the computer.
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Programm cook time into the computer.
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Replace relay.
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Lower to specified gas pressure.
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Raise to specified gas pressure.
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5---4