|
| If there is a |
|
| to maximum temperature (see installation |
|
| operations manual for temperature adjustment). |
|
| With the control set at maximum temperature, |
|
| check for supply voltage at mercury contactor. If |
|
| there is voltage at the mercury contactor, proceed |
|
| to “mercury contactor” for next check. If there is no |
|
| voltage at the mercury contactor, trace wiring back |
|
| to the oven control. If there is no voltage output at |
|
| the oven control, check the |
|
| control. If the control reads “PROBE FAIL”, this |
|
| indicates that the thermocouple has failed or |
|
| become disconnected from the oven control. |
| Thermocouple | Check to be sure that the thermocouple is |
|
| securely connected to the oven control. If the |
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| thermocouple is connected to the oven control, |
|
| and the control indicates “PROBE FAIL”, |
|
| disconnect the thermocouple from the oven |
|
| control and measure the resistance of the |
|
| thermocouple. The thermocouple should read |
|
| approx. 11Ω. If these readings are not achieved, |
|
| replace the thermocouple. If these readings are |
|
| correct, proceed. |
| Oven control | If the thermocouple checks good, but the oven |
|
| control display indicates that there is a |
|
| thermocouple failure, replace the oven control. If |
|
| the oven control indicates a temperature reading |
|
| but the oven will not heat, proceed. |
| Thermocouple | WITH POWER ON AND THERMOCOUPLE |
|
| ATTACHED TO THE OVEN CONTROL: Measure |
|
| the DC millivolt output of the thermocouple. Refer |
|
| to the thermocouple chart (located in the |
|
| “Removal” section of the manual) for proper |
|
| millivolt readings. If these readings are not |
|
| achieved, replace thermocouple. |
| Oven control | If the thermocouple checks good, but there is no |
|
| voltage output to the mercury contactor, replace |
|
| the oven control. If there is voltage output to the |
|
| mercury contactor, proceed. |
| Mercury contactor | Check for supply voltage to the contactor coil. If |
|
| voltage is present and the contactor will not |
|
| activate, replace the mercury contactor. Also |
|
| check each contactor for high voltage input and |
|
| output. |
| Heating element(s) | Check the Amp draw on each power leg for proper |
|
| load. Check the specification plate for rating |
|
| information. If the amp draw is high or low, check |
|
| the individual elements for opens, shorts and |
|
| proper resistance. |
|
| WITH POWER OFF: To check resistance of the |
|
| elements, remove all leads from the elements and |
|
| use a digital multimeter. |
|
| The element resistance is should be as follows: |
|
| 208V – 27 ohms approx. |
|
| 240V – 36 ohms approx. |
|
| Replace heating elements as needed. |
Oven heats with switch off | Mercury contactor | The mercury contactor has probably failed in the |
|
| closed position. If there is no voltage to the |
|
| operating coil, but there is high voltage at the |
|
| contactor output, replace the mercury contactor. |
Intermittent heating | Thermal/overload of motor | The main fan motor is equipped with internal |
18 | Impinger II – Advantage Digital Express Service Manual - Domestic |
