Introduction - Bradford White UPV Series Service Manual

Introduction

The new Bradford White URG1PV & URG2PV 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 Bradford White Defender Safety System ® (not available on all models).
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 - Developed for ease of
troubleshooting by providing simple diagnostic codes to pinpoint an installation or component
performance issue.
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.
Concealed wiring connections - Provide simple error-free wiring.
Increased Vent Lengths - Increased venting performance is achieved while maintaining Energy
Factor & FHR (not applicable on all models) performance.
The URG1PV & URG2PV water heaters use a combustion system where flue gases are combined
with dilution air to reduce the flue gas temperature in the blower. The diluted flue gases are
evacuated to the exterior through low temperature 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.
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, 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 they 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.
The gas control utilizes a flammable vapor sensor to detect the presence of flammable vapors and
shut down if the vapors achieve a certain level.
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