Flame will not stay on | Flame sensor | To check for flame sensor operation, connect a |
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| digital multimeter (capable of measuring DC |
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| microamps) between the flame sensor wire and |
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| terminal #1 on the ignition control. Sensor |
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| current is to be 3 microamps, minimum. If |
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| these readings are not achieved, replace |
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| igniter sensor assembly. Also, check for any |
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| type of damage to flame sensor wire and |
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| connections. NOTE: The DC microamp test |
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| must be conducted with the oven in low flame |
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| (bypass) operation. |
| Power supply | Turn the temperature to the lowest temperature |
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| setting. If there is sufficient microamp current, |
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| but the flame will not stay lit, check for proper |
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| polarity of the power supply. |
| Ignition control | If there is sufficient flame sensor current, but |
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| the burner will not remain ignited, check the |
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| reset button on ignition control. If all above test |
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| okay, replace ignition control. |
| NOTE: Flame should be lit at |
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| this time |
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Low flame is on, but no main | Temperature control | Check for supply voltage at terminal #7 to L2 |
flame |
| on temperature control. If there is no voltage, |
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| trace wiring back to oven fan switch. Turn the |
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| temperature adjustment knob to maximum |
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| temperature position and check for supply |
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| voltage at the load terminal #8 and L2. If |
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| voltage is present and unit is not heating, refer |
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| to “Temperature regulation valve” for next |
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| check. If voltage is not present, proceed. |
| Thermocouple | With power on and thermocouple leads |
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| attached to the temperature control board: |
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| Measure the DC millivolt output of these leads. |
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| Refer to thermocouple chart in “removal and |
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| installation” section for proper readings. If |
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| these readings are not achieved, replace |
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| thermocouple. |
| Temperature potentiometer | Disconnect the potentiometer leads from the |
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| temperature control board. Place ohmmeter |
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| test leads on the blue and green pot. leads. |
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| Reading should be 1K ohms. Place meter |
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| leads on the blue and purple pot. leads and |
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| rotate knob from high to low. Repeat on green |
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| and purple leads. Check for an even rise and |
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| fall of ohms reading to insure that there are no |
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| open or dead spots in the potentiometer. |
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| Check each lead to ground for any short |
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| circuits to ground. Replace as needed. |
| Temperature regulation valve | If supply voltage is present on the temperature |
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| control board at load terminals #8 and L2, |
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| check for voltage at temperature regulation |
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| valve. If voltage is present, listen for valve to |
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| open and close. Also check for opens or shorts |
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| in the operating coil. Replace as needed. |
Intermittent heating | Thermal overload of main fan | The main fan motor and burner blower motor |
| and burner blower motors | are equipped with internal thermal protection |
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| and will cease to operate if overheating occurs. |
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| As these motors overheat and then cool, the |
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| burners will cycle on and off intermittently. |
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| Improper ventilation or a lack of preventive |
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| maintenance may cause this condition. Also, |
8 | Impinger II – | |
