Bradford-White Corp U4TW40T*FRN Manual De Usuario

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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 new gas valve can be removed and replaced 
without draining the water heater.  A special tool is required and will be provided with each gas 
valve kit shipped from our Service Parts department.   
Please read the service manual completely before attempting service on this new series of 
power
How the Safety System Works
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.
How to Use this Manual 
It is intended for this manual to be used by qualified service personnel for the primary purpose 
of troubleshooting and repair of the Bradford White Residential Flue Damper water heaters. 
Understanding the sequence of operation section of this manual will contribute greatly to 
troubleshooting the water heater. 
The Honeywell WV4460E Electronic Gas Control will display error codes in the event of
abnormal operation. Error codes are listed in the troubleshooting chart beginning on page 13 of 
this service manual. The troubleshooting chart will also indicate the probable cause for the error 
code and direct the service professional to a service procedure to properly diagnose the 
abnormal operation. 
How to Use this Manual 
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