What is a Gas Burner Assembly?

Gas burner assembly or gas supply is an important element in the water heater. It consists of a thermocouple, main orifice, main gas supply tube, pilot burner (or pilot lights), pilot orifice and pilot burner gas supply. Gas burner ports are located on top of each side of the steel flame spreader plate; they connect the main gas supply tube to the inner circular openings through which oxygen enters from below. The burners come with an access door that is used for adjusting the air shutter to keep it open enough for proper combustion but not too open as to prevent shutting off due to low-limit control failure during times when no water is being drawn through the heating mechanism. Gas orifices are normally located behind the pilot burner.

The Gas Burner Assembly is usually made of cast iron and has three parts:

• the base, which contains a double spiral-type main gas supply tube (preheating), pilot orifice, thermocouple, pilot burner, pilot assembly with orifices and 4-way valve;
• the middle part containing flame spreader plate including six to eight holes with double spirals for outer air intake with openings at bottom of the appliance;
• the top which contains inner burners with dual concentric openings that extend through the hollow center of circular steel plate into burner tubes where it terminates in two outlets with one opening on each side of the steel flame spreader plate.

Gas burner ports are located on top of each side of the steel flame spreader plate; they connect the main gas supply tube to the inner circular openings through which oxygen enters from below. Gas is supplied via a flexible stainless steel line by a solenoid valve controlled by a thermostat or high limit switch. Gas pressure regulator and water pressure regulator is installed between the meter and flex line.

Main Gas Supply Tube – It runs from the solenoid valve to manifold, down across where it drops into two passages in the preheat section that come together just below orifice.

Pilot Orifice – A small hole for controlling pilot gas flow manually during shut-off periods when no hot water is drawn through the heating mechanism.

Pilot Burner – It is a small burner that lights the main burner when the thermostat calls for heat or when gas control valve is pushed open manually during shut-off periods when no hot water being drawn through the heating mechanism. Gas is supplied via a flexible stainless steel line by a solenoid valve controlled by a thermostat or high limit switch.

Thermocouple – A safety device that shuts off the gas to main burners if it detects insufficient oxygen in the combustion chamber.

4-way Gas Valve – An on/off, automatic/manual function handle with four brass connections used for igniting, adjusting flame height, shutting down, and locking out controls of the furnace assembly that are not safe for servicing. The gas control valve is located at the end of the thermocouple and feeds the pilot burner thru a jet; it’s operated by push-pull action on the lever handle.

Pilot Assembly – It includes orifice (located behind pilot assembly), burner tube, a double air shutter & seat ring, screen/filter and nozzle with plug where all these pieces are assembled in one unit for operating the pilot flame system. Gas entering through an adjustable air shutter goes to each side of the inner circular opening and then into and across burner tubes that extend through the hollow center of circular steel plate into burners. Gas exits out two outlets on each side of the steel flame spreader plate to portholes which start a manifold connected to the main gas supply tube. Gas is then distributed to main burners. Gas enters manifold directly into an orifice and is then divided into two openings that intermingle at the bottom of the appliance before spreading out for combustion.

burner gas supply. Gas burner ports are located on top of each side of the steel flame spreader plate; they connect the main gas supply tube to the inner circular openings through which oxygen enters from below. The burners come with an access door that is used for adjusting the air shutter to keep it open enough for proper combustion but not too open as to prevent shutting off due to low-limit control failure during times when no water is being drawn through the heating mechanism. Gas orifices are normally located behind the pilot burner.

The Gas Burner Assembly is usually made of cast iron and has three parts:

• the base, which contains a double spiral-type main gas supply tube (preheating), pilot orifice, thermocouple, pilot burner, pilot assembly with orifices and 4-way valve;
• the middle part containing flame spreader plate including six to eight holes with double spirals for outer air intake with openings at bottom of the appliance;
• the top which contains inner burners with dual concentric openings that extend through hollow center of circular steel plate into burner tubes where it terminates in two outlets with one opening on each side of the steel flame spreader plate.

Gas burner ports are located on top of each side of the steel flame spreader plate; they connect the main gas supply tube to the inner circular openings through which oxygen enters from below. Gas is supplied via a flexible stainless steel line by a solenoid valve controlled by a thermostat or high limit switch. Gas pressure regulator and water pressure regulator is installed between the meter and flex line.

Main Gas Supply Tube – It runs from the solenoid valve to manifold, down across where it drops into two passages in the preheat section that come together just below orifice.

Pilot Orifice – A small hole for controlling pilot gas flow manually during shut-off periods when no hot water is drawn through the heating mechanism.

Pilot Burner – It is a small burner that lights the main burner when the thermostat calls for heat or when gas control valve is pushed open manually during shut-off periods when no hot water being drawn through the heating mechanism. Gas is supplied via a flexible stainless steel line by a solenoid valve controlled by a thermostat or high limit switch.

Thermocouple – A safety device that shuts off the gas to main burners if it detects insufficient oxygen in the combustion chamber.

4-way Gas Valve – An on/off, automatic/manual function handle with four brass connections used for igniting, adjusting flame height, shutting down, and locking out controls of the furnace assembly that are not safe for servicing. The gas control valve is located at the end of the thermocouple and feeds the pilot burner thru a jet; it’s operated by push-pull action on the lever handle.

Pilot Assembly – It includes orifice (located behind pilot assembly), burner tube, a double air shutter & seat ring, screen/filter and nozzle with plug where all these pieces are assembled in one unit for operating the pilot flame system. Gas entering through an adjustable air shutter goes to each side of the inner circular opening and then into and across burner tubes that extend through the hollow center of circular steel plate into burners. Gas exits out two outlets on each side of the steel flame spreader plate to portholes which start a manifold connected to the main gas supply tube. Gas is then distributed to main burners. Gas enters manifold directly into an orifice and is then divided into two openings that intermingle at the bottom of the appliance before spreading out for combustion.