Whirlpool 4322452 Service Manual page 48

As this is taking place, the thermostat also opens the main gas line, and provides gas to the safety
valve (see Figure 4-6). As soon as the safety valve is hydraulically opened by the signal from the
sensing bulb, gas is released from the safety valve to the oven burner, and ignited by the heater
pilot flame. NOTE: If the heater pilot flame is not available to heat the safety valve sensing bulb,
the safety valve will not open, and gas can not enter the oven.
Pressure Forces
Contact Against
Switch & Opens Valve
Heater Flame
Heats Sensor
Gas Safety Valve Open
When the oven reaches the selected temperature, the sensing bulb for the thermostat closes the
thermostat gas lines and reduces the heater pilot flame back to a smaller "standing pilot" flame.
With no heater pilot flame, the sensing bulb for the safety valve cools, closes the safety valve, (see
Figure 4-7), stops the gas supply to the oven burner, and eliminates the flame. This cycling will
continue for the duration of the cooking cycle.
Heater Sensing
Bulb & Capillary Tube
Cold Sensor
Gas Safety Valve Closed
Safety Valve
Orifice Hood
Safety Valve
Page 4-4
Gas Flows Out
Orifice Hood
Valve Opens & Gas
Flows To Oven Burner
Gas Inlet
(From Thermostat)
Figure 4-6
Valve Closed
No Gas Flow
Gas Inlet
(From Thermostat)
Figure 4-7