FULL SIZE ELECTRIC CONVECTION OVENS - SERVICE PROCEDURES AND ADJUSTMENTS
TEMPERATURE PROBE TEST |
| HEATING ELEMENT TEST |
(SOLID STATE CONTROL) |
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WARNING: DISCONNECT THE ELECTRICAL POWER TO THE MACHINE AT THE MAIN CIRCUIT BOX. PLACE A TAG ON THE CIRCUIT BOX INDICATING THE CIRCUIT IS BEING SERVICED.
NOTE: The temperature probe used in conjunction with the Solid State Temperature control is an RTD (resistance temperature detector) of the Thermistor type. As temperature increases the resistance value decreases.
1.Remove the right side panel as outlined under "COVERS AND PANELS" in "REMOVAL AND REPLACEMENT OF PARTS".
NOTE: If right side panel is not accessible, this component can be serviced by removing the control panel as outlined under "COVERS AND PANELS".
2.Place a shielded thermocouple in the geometric center of the oven cavity and determine the temperature in the oven cavity.
3.Remove the probe lead wires from the solid state temperature control.
4.Test the probe with an ohmmeter.
A.If the measured resistance values are inside the given tolerance then the probe is functioning properly.
B.If the measured resistance values are outside the given tolerance then replace the probe and retest.
1)Check oven for proper operation.
5.Reverse procedure to install.
TEMP (°F) | OHMS* | TEMP (°F) | OHMS* |
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77 | 90,000 | 360 | 822 |
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240 | 4,077 | 380 | 656 |
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260 | 3,016 | 400 | 529 |
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280 | 2,266 | 425 | 424 |
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300 | 1,726 | 450 | 334 |
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320 | 1,332 | 475 | 266 |
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340 | 1,041 |
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(*) Resistance in ohms ± 10%
WARNING: THE FOLLOWING STEPS REQUIRE POWER TO BE APPLIED TO THE UNIT DURING THE TEST. USE EXTREME CAUTION AT ALL TIMES.
1.Turn the power switch ON and set the oven temperature control to the highest setting.
2.Measure the voltage at the heating element terminals and verify it against the data plate voltage.
A.If voltage is incorrect, find the source of the problem.
B.If voltage is correct, check current draw (amps) through the heating element lead wires.
NOTE: This method is preferred over a resistance check when a clamp on type amp meter is available.
1)If current draw is correct then heating element is functioning properly. See table below for proper values.
2)If current draw is not correct, turn the power switch OFF and disconnect the electrical supply to the oven.
a.Replace heating element then proceed to step 3.
C.If unable to check current draw, a resistance check may indicate a malfunctioning element.
1)Turn the power switch OFF and disconnect the electrical supply to the oven.
2)Remove the lead wires from the heating element and check resistance (ohms). See table below for proper values.
3.Check for proper operation.
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VOLTAGE | KW PER | ELEMENT | OHMS PER | ||
ELEMENT | LEAD | ELEMENT | |||
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| 1 PH | 3 PH |
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208 |
| 2 | 60 | 35 | 21 |
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240 |
| 2 | 52 | 33 | 28 |
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480 |
| 2 | 15 | 4 | 111 |
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NOTES: | 1. | Values in the table are nominal. | |||
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| Tolerance is |
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| 2. | Voltage values are @ 60HZ. | |||
| 3. | Resistance values (ohms) are @ | |||
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| room temperature. |
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F25105 (December 2001) |
| Page 20 of 60 |
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