Gas Control Valves
Manual Gas Control Valve System Components
The manual control valve system is an assembly consisting of a manual control knob assembly and internal and external parts of the safety pilot system.
anual Valve: Gas Control Knob Assembly
The control knob (also referred to as the gas cock) assembly includes:
- a round plastic knob, marked with three positions (PILOT, ON, and OFF), that rotates and can be pushed in a solid shaft moved and rotated by the knob a rod connected to the center of the shaft (inside the valve) that presses against and unseats the shutoff disc of the EPU (electromagnetic power unit) when the knob is pushed in.
- a cylinder connected to the shaft, and which surrounds the rod, that has an opening that allows and directs gas flow when rotated and aligned with portals that lead to the pilot and main burners.
The control knob assembly is the manual adjustment mechanism that allows gas flow to the pilot hood, holds the valve open until the safety pilot system is energized, and then can be positioned to allow gas flow to the main burner. It is also the means for turning the appliance off in normal shutdown.