The interaction between the thermostat and the safety valve is very important and critical to the operation of the oven. The thermostat provides two separate functions each time it is turned on, but first, we need to know what the thermostat does when it is in the “OFF” position. Even with the thermostat in the “Off” position, a supply of gas from the manifold pipe is always available through the thermostat to the oven pilot assembly. It supplies enough gas to maintain a constant or “standing” pilot flame in the oven at all times (see Figure
Standing
Pilot Flame
Standing Pilot
Assembly
BROIL
OFF | T |
PA
L N
550
500
OFF
200
250
300
350
450 | 400 |
|
Figure | The Standing Pilot | |
Thermostat Off | ||
|
When the thermostat is turned “ON” to any temperature, its primary function is to increase the flow of gas to the oven pilot assembly so that the “standing” pilot flame enlarges to create a “larger standing pilot” or a “heater pilot flame.” This larger flame is deflected by a flame spreader (see Figure
Heater Pilot
Flame Spreads
Down To Sensing Bulb
Flame Spreader
Safety Valve
Sensing Bulb
Heater Pilot
Flame Wraps
Around Sensor
|
|
| 200 | 250 |
|
|
|
| |
| OFF |
|
| 300 |
|
|
| 350 | |
P | OFF | T |
| 400 |
| A |
|
| |
|
|
|
| |
L |
| N |
|
|
| BROIL |
| 450 | |
|
|
|
| |
|
|
|
| 500 |
|
|
|
| 550 |
The Standing Pilot
Thermostat On
Figure
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