| Spark Ignitor (Flame Sensor) | (There should be a visible pilot flame at this time). |
Pilot flame but no main |
| NOTE: The Honeywell Ignition Control uses the |
flame |
| spark ignitor as the flame sensor. If spark |
|
| continues, check for proper ground connections at |
|
| Ignition Control. Check pilot orifice for any partial |
|
| blockage. If the above checks OK, replace ignition |
|
| control. If spark stops when pilot is lit, check for 24 |
|
| VAC across M.V. - M.V/ P.V. terminals, if voltage is |
|
| not present, replace ignition control. If voltage is |
|
| present at terminals M.V. - M.V./P.V., the indicator |
|
| light on the control panel should be on, verify that |
|
| the main valve has opened, connect manometer to |
|
| manifold gas pressure tap(located on the |
Red Indicator Light is | Temperature Control Valve | Check for gas supply at temperaturecontrol. Check |
on, but no main | (Robert Shaw) | for temperature control set above 300°F. |
flame(For ovens with | Main Orifice | Check for blockage of main orifice. If there is no |
mechanical |
| blockage to the main orifice, replace the |
thermostat) |
| temperature control. |
(For ovens with | Temperature Control | Check for 120 VAC across L1 and L2on |
Electronic | Potentiometer | temperature control board. Potentiometer (1000 |
Temperature Control) |
| ohm,1 turn) WITH POWER OFF: check ohms |
|
| across red and black leads, the ohm reading |
|
| should be 0 to1000 ohms as the dial is turned. |
|
| From green to red, the reading should be 1000 |
|
| ohms steady throughout the full turn of the dial. |
NOTE: Ovens S/N Q18037 and above, the potentiometer is internal to temperature control. Proceed to next | ||
component. |
|
|
| Thermocouple Probe | Remove thermocouple leads from the temperature |
|
| control board, and measure the millivolt output of |
|
| these leads. Refer to chart on page 38 in the |
|
| adjustment section for proper readings. |
| Temperature Control | Turn temperature control dial to full "on" position. |
|
| Measure for 120 VAC across terminals "N.O." and |
|
| "L2", if voltage is not present; replace control. |
| Solenoid Valve | If voltage is present at terminals "N.O."and "L2", |
|
| check for voltage at solenoid valve. If voltage is |
|
| present, listen for valve to open and close. Also, |
|
| check for opens and shorts in coil. If solenoid valve |
|
| is defective, replace |
Intermittent Heating |
| Both the main fan motor and burner blower motor |
|
| are equipped with |
|
| to operate when not cooled properly. This can |
|
| cause the units to cycle on and off intermittently. |
|
| Also, most of the problems listed under "oven will |
|
| not heat" can cause intermittent failures. |
For continuing intermittent problems, a series of test lights may be made and installed in
the ovens. The lights will allow the customer to advise the service technician a trouble code when the oven fails.
The lights should be connected in the following manner: |
| |
Light#l attached in 120VAC line after Air Pressure Switch. |
| |
Light#2 attached after 120VAC contacts of Burner Motor Relay (or, refer to Bulletin #028 |
| |
for Relay Removal). |
|
|
Light#3 in 24VAC Burner Transformer Secondary. |
| |
Light#4 in 24VAC at terminal #6 of Johnson control valve or "24V" on Honeywell Control. |
| |
Light#5 in 24VAC at terminal #1 of Johnson control valve or "PV" on Honeywell Control. |
| |
Light#6 in 24VAC at terminal #3 of Johnson control valve or "MV" on Honeywell Control. |
| |
CODE: |
|
|
All lights off - lights of main power, main fan off, air pressure switch out. |
| |
1 on 2 off 3 on 4 off 5 off 6 off | - Burner Motor Relay bad. |
|
Impinger I | 23 |