| 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 won’t |
|
| 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 |
|
| 120VAC output to the temperature regulation valve, |
|
| replace the oven control. If there is 120VAC output to |
|
| the temperature regulation valve, proceed. |
| Temperature regulation valve | Check for 120VAC supplied to temperature |
|
| regulation valve. If voltage is present, listen for valve |
|
| to open and close. Also check for opens or shorts in |
|
| the operating coil. Replace temperature regulation |
|
| valve as needed. |
Intermittent heating | Thermal/overload of main fan | The main fan motor and burner blower motor are |
| and burner blower motors | equipped with internal thermal protection and will |
|
| cease to operate if overheating occurs. As the |
|
| motors overheat and then cool, this will cause the |
|
| heating system to cycle on and off intermittently. |
|
| Improper ventilation or lack of preventive |
|
| maintenance may cause this problem. Also, most of |
|
| the problems listed under “Oven will not heat” can |
|
| cause intermittent failure. |
Conveyor will not run | Power supply | Check for incoming voltage at line 1 to neutral. There |
|
| should be a reading of 120VAC. If not present, check |
|
| circuit breakers. |
| Fuse, 10 Amp | Check, replace if necessary. |
| Fuse holder | Check, replace if necessary. |
| Check for voltage on both sides of switch. Terminals | |
|
| are normally closed. If open, reset and test oven for |
|
| proper operation. If thermostat will not hold, and |
|
| control box temperature is not exceeding 140°F |
|
| (60°C), replace thermostat. |
| Power switch | Check continuity between switch terminals. Replace |
|
| switch as needed. |
| Control transformer | Check for 120 VAC supply to the primary of the |
|
| control transformer. If no voltage is present, trace |
|
| wiring back to the oven power relay. If voltage is |
|
| present, check for 24 VAC at the transformer |
|
| secondary. If there is primary voltage but no |
|
| secondary voltage, replace control transformer. |
| Conveyor motor | Check for 120 VAC supply to the conveyor motor at |
|
| wire #14 to neutral. If no voltage is present, trace |
|
| wiring back to the primary of the control transformer. |
|
| If voltage is present and the motor will not run, check |
|
| the motor windings for opens or shorts. |
|
| WITH POWER OFF: Check the motor windings as |
|
| follows: |
|
| Grey to black - 38Ω approx. |
|
| Grey to blue - 38Ω approx. |
|
| Blue to black - 75Ω approx. |
|
| If any of the above fails, replace conveyor motor. |
| Capacitor, conveyor motor | Check for shorts or grounds. Replace capacitor as |
14 | Impinger II – Advantage Digital Express Service Manual - Domestic |