Bradford-White Corp U130T*FRN User Manual

The Bradford White ECO-DEFENDER Safety System was designed to 

resist the ignition of flammable vapors that can occur outside of the water 

heater.  In addition, the ECO-DEFENDER Safety System is designed to 

meet the stringent NOx emissions standards required in the South Coast 

Air Quality Management District (SCAQMD) Rule 1121.  Use and 

installation are nearly identical to previous versions of atmospherically 

fired and vented water heaters.  A number of exclusive design features are 

incorporated in the system that will require additional knowledge on the 

part of the qualified service provider.  The following information will 

instruct service professionals on the function, proper diagnosis and repair 

of water heaters employing the Bradford White ECO-DEFENDER Safety 

System.

During normal operation, most air for combustion is drawn into the water 

heater through the openings in the jacket door.  This air travels into the 

burner venturi, mixing with the gas jet.  This air is then mixed with gas 

inside the burner and drawn to the burner screen and is efficiently 

combusted producing Ultra Low NOx emissions.  Additional air is drawn 

through the openings in the jacket. This air travels down and around the 

combustion chamber and enters through holes in the bottom of the 

corrosion-resistant combustion chamber.  The air then travels up through 

the oriented flame arrestor plate louvers, where the velocity of the air is 

increased and its direction altered.  The air then mixes in a normal manner 

with the combustion products from the burner. 

In the case where trace amounts of flammable vapors are present in the air 

flowing into the combustion chamber and burner venturi, the vapors are 

harmlessly ignited by the burner / pilot flame.  If flammable vapors are in 

sufficient quantity to prevent normal combustion, the burner and pilot 

flames are designed to shut down.

Should the flammable vapors continue to the burner, the flame arrestor 

plate and burner screen prevent the flames from traveling backwards and 

igniting vapors outside of the combustion chamber.  This causes the 

thermopile to overheat and shuts down the main pilot and burner. The 

thermopile powers the intelligent diagnostic control which is capable of 

recognizing restricted airflow conditions caused by severe lint, dust and 

oil accumulation on the burner screen and arrestor plate. The intelligent 

diagnostic control will deactivate the burner and pilot in the unlikely event 

of restricted airflow.

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