Bradford White PE-2-XR504T6FSX - Manual (Page 5)

Page 5
The Bradford White DEFENDER Safety System ®
The Bradford White DEFENDER Safety System was designed to resist the ignition of
flammable vapors that can occur outside of the water heater. 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 DEFENDER Safety System.
Introduction
The new Bradford White Programmable Efficiency water heaters are designed to provide
reliable performance with enhanced standard features. New design features include reliable
spark-to-pilot ignition system, enhanced diagnostics, simplified servicing, and the Bradford
White Defender Safety System.
Spark-to-Pilot Ignition System - employing the spark-to-pilot ignition system promotes
reliable and consistent pilot and main burner ignitions to provide hot water on demand.
Integrated Immersion Thermal Well/Gas Control with LED - was developed for ease of
troubleshooting by providing simple diagnostic codes to pinpoint an installation or component
performance issue.
Rugged Wiring Connections - receptacle type connections promote error free wiring.
The gas control maintains water temperature, ignition sequence, and regulates gas flow. If a
situation outside of normal operating parameters exists, the gas control diagnostic LED will
flash a code to positively identify an operational issue.
This service manual is designed to facilitate problem diagnosis and enhance service efficiency.
To further promote quicker service times, the gas control can be removed and replaced without
draining the water heater. A special tool is required and will be provided with each gas control
kit shipped from your Bradford White wholesale distributor.
Please read the service manual completely before attempting service on this new series of
models.
How the DEFENDER Safety System Works
During normal operation, air for combustion is drawn into the water heater through the
openings in the jacket. This air travels down and around the combustion chamber and enters
through holes in the very bottom of the corrosion resistant combustion chamber. The air then
travels up through the flame arrestor louvers, where the velocity of the air is increased and its
direction altered. The air then mixes in a normal manner with supplied gas and is efficiently
combusted, producing very low NO
x
emissions.
In the unlikely event trace amounts of flammable vapors are present in the air flowing into the
combustion chamber, the vapors are harmlessly ignited by the burner. If flammable vapors are
in sufficient quantity to prevent normal combustion, the flammable vapor sensor recognizes
this and shuts down the pilot and main burner. Should the flammable vapors continue to burn,
the flame arrestor prevents the flames from traveling backwards and igniting vapors outside of
the combustion chamber. In addition, the resettable thermal switch will open and shut down
the pilot and main burner.
Introduction
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