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The new Bradford White PDX1, PDX2 and PDX4 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, significantly quieter
operation, additional vent lengths and certified FVIR technology.
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 Thermostat/Gas Control Valve with LED - was developed for ease
of troubleshooting by providing simple diagnostic codes to pinpoint an installation or
component performance issue.
New Powerful Blower - will eliminate problems with difficult venting situations.
Quieter and Cooler Blower Operation - blower noise is significantly reduced for both
interior and exterior environments. Cooler operation increases blower life by reducing bearing
wear and noise.
Rugged Wiring Connections - receptacle type connections promote error free wiring.
Increased Vent Lengths - increased venting performance is achieved while maintaining
Energy Factor & FHSR performance.
The PDX1, PDX2, and PDX4 water heaters use a combustion system were flue gases are
combined with dilution air to reduce the flue gas temperature in the blower, combustion air and
dilution air are drawn from outside the building. The diluted flue gases are evacuated to the
exterior through non metallic vent materials. The gas control maintains water temperature,
ignition sequence and regulates gas flow. A safety circuit consisting of a pressure switch and
blower temperature switch verifies proper conditions exist for safe and reliable operation. 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 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 vent models.
How the Safety System Works
During normal operation, air for combustion is drawn into the water heater though the vent pipe from outside your
building. The air travels into the closed combustion chamber. The air then mixes with in a normal manner with
supplied gas and its efficiently combusted, producing very low NOx emissions.
In the unlikely event trace amounts of flammable vapors are present in the area surrounding the water heater, the
sealed combustion system prevents the flammable vapors from reaching the ignition source. In addition the
flammable vapors sensor will stop the water heater from operating if a significant amount of flammable vapors are