Bradford White RG2F40S*(N,X) User manual

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Manual 238-51617-00A
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
RG2F40S*(N,X)
RG2F50S*(N,X)
(*) Denotes Warranty Years
Atmospheric Vent Gas Water Heater
High EF

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Table of Contents
Section Page
Introduction ______________________________________________ 5
How to Use this Manual _____________________________________ 6
Tools Required for Service___________________________________ 6
Specifications_____________________________________________ 7
Sequence of Operation _____________________________________ 9
Power Up Sequence
Normal Heating Sequence
Abnormal Operation
Troubleshooting __________________________________________ 13
Burner Maintenance_______________________________________ 15
Burner Inspection
Burner Cleaning Procedure
Pilot Maintenance_________________________________________ 17
Pilot Inspection, Testing and Replacement
Blower Replacement ______________________________________ 19
Gas Control Testing & Replacement __________________________ 21
Determine Temperature Inside Tank _____________________ 21
Gas Control Removal _________________________________ 22
Flammable Vapor Sensor Testing ____________________________ 23
120 VAC Circuit Trace _____________________________________ 23
Diptube Inspection _______________________________________ 24
Anode Inspection_________________________________________ 25
Blower Removal__________________________________________ 25
Inner Door Removal ______________________________________ 28
Inner Door Gasket Replacement _____________________________ 30
Inner Door Installation ____________________________________ 31
Pressure Switch Testing & Replacement _______________________ 32
Arrestor Cleaning_________________________________________ 34
Common Terms __________________________________________ 35
Parts List _______________________________________________ 36
Notes __________________________________________________ 37

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WARNING
If the information in these instructions is not followed exactly, a fire or explosion may
result causing property damage, personal injury, or death.
What to do if you smell gas:
x Do not try to light any appliance
x Do not touch any electrical switch; do not use any phone in your building
x Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s
instructions.
x If you cannot reach your gas supplier, call the fire department.
Installation and service must be performed by a qualified installer, service agency, or the
gas supplier.
CAUTION
Incorrect operation of this water heater may create a hazard to life and property and will
nullify the warranty.
If sweat fittings are to be used, DO NOT apply heat to the nipples on top of the water
heater. Sweat the tubing to the adapter before fitting the adapter to the water
connections. It is imperative that heat is not applied to the nipples containing a plastic
liner.
Turn off or disconnect the electrical power supply to the water heater before servicing.
Label all wires prior to disconnection when servicing controls. Wiring errors can cause
improper and dangerous operation. Verify proper operation after servicing.
DANGER
Do not store or use gasoline or other flammable, combustible, or corrosive vapors and
liquids in the vicinity of this or any other appliance.
NOTICE
Before proceeding, please inspect the water heater and its components for possible
damage. DO NOT install any water heater with damaged components. If damage is
evident, then please contact the supplier where the water heater was purchased or the
manufacturer listed on the rating plate for replacement parts.
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WARNING
Water heaters are heat producing appliances. To avoid damage or injury, do not store
materials against the water heater or any of its components. Use proper care to avoid
unnecessary contact, especially by children, with the water heater and its components.
Under no circumstances must flammable materials, such as gasoline or paint thinner be
used or stored in the vicinity of this water heater or in any location in which the fumes
could reach the water heater.
Hydrogen gas can be produced in an operating water heater that has not had water drawn
from the tank for a long period of time (generally two weeks or more). Hydrogen gas is
extremely flammable. To prevent the possibility of injury under these conditions, we
recommend a hot water faucet to be open for several minutes at the kitchen sink before
you use any electrical appliance which is connected to the hot water system. If hydrogen is
present, there will be an unusual sound such as air escaping through the pipes as hot
water begins to flow. Do not smoke or have open flame near the faucet at the time it is
open.
DO NOT ATTEMPT TO LIGHT ANY GAS APPLIANCE IF YOU ARE NOT CERTAIN OF THE
FOLLOWING:
Liquefied petroleum gases/propane gas and natural gas have an odorant added by the gas
supplier that aids in the detection of the gas. Most people recognize this odor as a “sulfur”
or “rotten egg” smell. Other conditions, such as “odorant fade” can cause the odorant to
diminish in intensity, or ”fade,” and not be as readily detectable. If you have a diminished
sense of smell, or are in any way unsure of the presence of gas, immediately contact your
gas supplier from a neighbor's telephone. Gas detectors are available. Contact your gas
supplier, or plumbing professional for more information.
FAILURE TO INSTALL AND MAINTAIN A NEW, LISTED 3/4” X 3/4” TEMPERATURE AND
PRESSURE RELIEF VALVE WILL RELEASE THE MANUFACTURER FROM ANY CLAIM THAT
MIGHT RESULT FROM EXCESSIVE TEMPERATURE AND PRESSURES.

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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 High EF atmospheric vent gas 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.
Please read the service manual completely before attempting service on this new series of High
EF gas models.
How the 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 bottom. 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 low NOxemissions.
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
Introduction

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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. And, the resettable thermal switch will open and shut down the pilot and
main burner.
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 High EF atmospheric gas water heaters.
Understanding the sequence of operation section of this manual will contribute greatly to
troubleshooting the water heater.
The Honeywell WV4462 Electronic Gas Control will display status codes in the event of
abnormal operation. Status 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
status code and direct the service professional to a service procedure to properly diagnose the
abnormal operation.
Contact the Bradford White technical support group immediately if diagnosis cannot be made
using the methods described in this service manual.
Tools Required for Service
Manometer: A liquid “U” tube type or a digital (magna-helic) type can be used. This device is
used to measure gas and/or air pressure and vacuum.
Multi-Meter: A digital type is strongly recommended. This device is used to measure electrical
values. The meter you select must have the capability to measure volts AC, volts DC, amps,
micro-amps and ohms.
Electronic Probes: In some cases, standard multi-meter probes will damage or simply not be
effective to obtain certain voltage and ohm reading. It will be necessary to have special
electronic “pin” type multi-meter probes. These probes are available at most electronic
wholesale outlets.
Thermometer: Used to measure water temperature. An accurate thermometer is recommended.
Water Pressure Gage: Used to measure water supply pressure. Also used to determine tank
pressure by adapting to the drain valve of the heater.
Various Hand Tools: Pipe wrench, channel locks, open end wrenches (3/8", 7/16", 1/2"), 12"
crescent wrench, Allen wrench set, screw drivers (common & Phillips), torx bits, 1/4" nut
driver, pliers (common & needle nose), socket set, side cutters, wire cutters, wire strippers, wire
crimpers, torpedo level, small shop vac, step ladder, flashlight, and 5 gallon pail.
How to Use this Manual

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Power Supply Dedicated 120VAC, 60 Hz, 15A
Gas Supply Pipe
Minimum 1/2” (Schedule 40 black iron pipe
recommended)
Approved Gas Type Natural or Propane; unit must match gas type supplied
Gas Pressure 5” w.c. minimum for Natural Gas; 11” w.c. for Propane;
14” w.c. maximum for Natural Gas / Propane
Approved Vent Materials Single or Double Wall Metal Vent Pipe
Recommended Minimum
Clearance for Servicing 18” from top; 24” from front; 4” from sides and rear
Water Supply Pressure 150 psi maximum allowable working pressure; check local
codes for supply pressure
ECO Limit 188°F (87°C)
Temperature Setpoint Range 60°F (16°C) to 160°F (71°C); approximate temperatures
Pressure Switch Setting
(normal altitude) -0.20” w.c. (-0.10” for Hi-Alt.)
Specifications

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Ignition State Timing
Pre-purge 15 seconds
Trial for Ignition 90 seconds
Flame Stabilization Period 3 seconds
Interpurge 15 seconds
Flame Failure Response Time 1.5 seconds (2 second maximum; 1 second mini-
mum)
Postpurge 15 seconds
Pressure Switch Fault Delay (failed open/close) Retry after 2 minutes
Soft Lockout Retry after 5 minutes
ECO Limit Lockout Indefinite (See page 21 to reset)
Verify Resistive Delay Retry after 2 minutes (repeats 5 times)
Simulated Resistive Load Lockout Indefinite (cycle power to reset)
Hardware Status Lockout Indefinite (self clears if fault clears for at least 15
seconds)
Specifications
Wiring Diagram
Control Timings

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Power Up Sequence
1. Start-up: Upon power up, the gas control runs a safe start check with a typical
delay of 5 seconds.
2. Flammable Vapor Verification: The gas control verifies that the Flammable Vapor
Sensor is in the proper operating range prior to energizing any components. If the
sensor is within the proper range, the gas control resumes normal operation. If the
Flammable Vapor Sensor is out of range, the gas control LED immediately flashes
7 times with a 3 second pause.
Normal Heating Sequence
1. Thermostat Calls for Heat: Prior to energizing the blower, the gas control verifies
the safety circuit to see if it is in the correct state. Normal switch positions in the
safety circuit are as follows:
A) Pressure switch normally open;
B) Blower temperature switch normally closed.
If the safety circuit is closed, the gas control LED flashes 2 times with a 3 second
pause. The gas control waits 2 minutes. Then, the blower is energized for 30
seconds. This cycle repeats until the safety circuit opens.
2. Blower Energizes
3. Safety Circuit Check: If the safety circuit does not close within 30 seconds, the
gas control LED flashes 3 times with a 3 second pause. The blower runs for a
maximum of 30 seconds every 2 minutes trying to close the safety circuit. This
cycle repeats as long as there is a call for heat.
4. Blower Pre-Purge (15 seconds)
5. Trial for Pilot Ignition (90 seconds): The gas control lights the pilot by activating
the spark igniter and gas flow to the pilot burner. If flame is not sensed within 90
seconds, the spark igniter and gas flow are deactivated. The blower will postpurge,
and the gas control LED flashes 6 times then 1 time with a 3 second pause.
6. Main Burner Ignition: After pilot flame is sensed, the gas control activates the
main valve for main burner ignition. The gas control will ignore flame signals for 3
seconds to allow for the main burner to stabilize.
Sequence of Operation

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Normal Heating Sequence (cont’d)
7. Steady State Operation: During steady state operation, the gas control monitors:
Temperature Sensor: When the setpoint temperature is satisfied, the gas control is
shutdown, and the blower will postpurge for 15 seconds. The gas control LED
flashes a short flash once every 4 seconds (Idle status code).
Pressure Switch / Blower Temperature Switch: If either switch opens, the pilot and
main valves are shutdown. The blower continues to run for 30 seconds attempting
to close the circuit. The gas control LED flashes 3 times with a 3 second pause.
Flame Sensor: If flame is lost, the pilot and main valves are shutdown. The blower
runs for 15 seconds. The gas control attempts to re-light the pilot 4 times. If
unsuccessful, the blower is shutdown, and the gas control proceeds to a 5 minute
lockout. The gas control re-attempts to light the pilot starting at Normal Heating
Sequence #2.
8. Thermostat Satisfies: Gas control LED flashes once every 4 seconds.
9. Burner Off
10.Blower Postpurge (15 seconds)
Abnormal Operation
1. Flammable Vapor Sensor Fault:
A) If the resistance is greater than 70,000 ohms: The gas control immediately turns
off all outputs. The gas control waits and monitors resistance for 30 seconds. If the
resistance is greater than 65,000 ohms after 30 seconds, the gas control proceeds
to verify resistive delay for 2 minutes and flashes 7 times with a 3 second pause.
This process is repeated 5 times until the control either returns to normal operation
or proceeds to flammable vapor lockout.
B) If the resistance is below 240 ohms: The gas control immediately turns off all
outputs and proceeds to flash 8 times then 1 time with a 3 second pause. The
status self clears if the resistance returns to normal range for at least 15 seconds.
Sequence of Operation