Bradford White U1TW40S*FRN User manual

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Manual 238-48385-00A
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
U1TW40S*FRN
U1TW50S*FRN
U1TW60T*FRN
U2TW50T*FRN
U2TW65T*FRN
UTW450S60FR*N
UTW465S60FR*N
(*) Denotes Warranty Years
Residential Ultra Low NOx Gas Water Heaters
TTW Eco-Defender
®

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Table of Contents
Section Page
Introduction ______________________________________________5
How to Use this Manual _____________________________________6
Tools Required for Service ___________________________________7
Specifications _____________________________________________8
Sequence of Operation_____________________________________ 12
Power Up Sequence
Normal Heating Sequence
Abnormal Operation
Troubleshooting __________________________________________ 17
Burner Maintenance _______________________________________ 20
Burner Inspection
Burner Cleaning Procedure
Pilot Maintenance _________________________________________ 22
Pilot Inspection Testing and Replacement
Pressure Switch Testing and Replacement _____________________ 25
Blower Testing and Replacement _____________________________ 28
Blower Temperature Switch Testing and Replacement ____________ 31
Thermal Well Testing ______________________________________ 34
Determine Water Temperature Inside Tank_____________________ 35
Gas Control and Thermal Well Testing and Replacement __________ 36
Flammable Vapor Sensor Testing and Replacement ______________ 40
115 VAC Circuit Trace _____________________________________ 40
Safety Circuit Voltage Trace_________________________________ 42
Flue Baffle Inspection and Replacement _______________________ 43
Diptube Inspection and Replacement _________________________ 44
Anode Inspection and Replacement___________________________ 45
Inner Door Removal, Inspection and Replacement _______________ 46
Inner Door Gasket Replacement _____________________________ 47
Inner Door Installation_____________________________________ 48
ScreenLok ® Flame Arrestor Cleaning_________________________ 49
Common Terms __________________________________________ 50
Notes __________________________________________________ 50
Parts List _______________________________________________ 51
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WARNING
If the information in these instructions is not followed exactly, a fire or ex-
plosion may result causing property damage, personal injury, or death.
What to do if you smell gas:
xDo not try to light any appliance
xDo not touch any electrical switch; do not use any phone in your build-
ing
xImmediately call your gas supplier from a neighbor’s phone. Follow the
gas supplier’s instructions.
xIf 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 be-
fore servicing. Label all wires prior to disconnection when servicing con-
trols. 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 compo-
nents. 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 flam-
mable 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 fau-
cet 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 hydro-
gen 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 CER-
TAIN 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 peo-
ple recognize this odor as a “sulfur” or “rotten egg” smell. Other condi-
tions, 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 con-
tact your gas supplier from a neighbor's telephone. Gas detectors are
available. Contact your gas supplier, or plumbing professional for more in-
formation.
FAILURE TO INSTALL AND MAINTAIN A NEW, LISTED 3/4” X 3/4” TEM-
PERATURE AND PRESSURE RELIEF VALVE WILL RELEASE THE MANUFAC-
TURER FROM ANY CLAIM THAT MIGHT RESULT FROM EXCESSIVE TEM-
PERATURE AND PRESSURES.
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The Bradford White ECO-DEFENDER Safety System®
The Bradford White ECO-DEFENDER Safety System was designed to resist
the ignition of flammable vapors that can occur outside of the water heater
and produce Ultra Low NOx emissions. Use and installation are nearly iden-
tical to previous versions of atmospherically fired and vented water heaters.
Anumber of exclusive design features are incorporated in the system that
will require additional knowledge on the part of the qualified service pro-
vider. The following information will instruct service professionals on the
function, proper diagnosis, and repair of water heaters employing the Brad-
ford White ECO-DEFENDER Safety System.
Introduction
The new Bradford White TTW ECO-DEFENDER water heaters are designed to provide reli-
able performance with enhanced standard features. New design features include reliable spark
to pilot ignition system, enhanced diagnostics, simplified servicing, quiet operation, additional
vent lengths, Bradford White ECO-DEFENDER Safety System ® and Ultra Low NOx emis-
sions.
Spark-to-Pilot Ignition System - Employing the spark-to-pilot ignition system promotes reli-
able 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.
New Powerful Blower - Will eliminate problems with difficult venting situations.
Quieter and Cooler Blower Operation - Blower noise is significantly reduced for both inte-
rior 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 En-
ergy Factor and FHSR performance.
The TTW1, TTW2 & TW4 water heaters use a combustion system were flue gases are com-
bined 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 main-
tains water temperature, ignition sequence and regulates gas flow. A safety circuit consisting of
apressure 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
Introduction
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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 with-
out 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 effi-
ciently 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 trou-
bleshooting the water heater.
The Honeywell WV4460E Electronic Gas Control will display error codes in the event of ab-
normal 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 abnor-
mal operation.
How to Use this Manual
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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: Aliquid “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: Adigital 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 elec-
tronic “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.
Gas Control Service Tool: BWC part number 239-45991-00. A specialized tool designed to
remove the gas control from gas control thermal well. Available from your Bradford White
parts supplier.
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), 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.
Tools Required
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Power Supply Dedicated 115VAC, 60 Hz, 15A.
Gas Supply Pipe Minimum 1/2” NPT (schedule 40 black iron pipe recommended).
Approved Gas Type Natural Gas.
Gas Pressure 6.0” W.C. minimum, 11.0” W.C. maximum.
Venting System Power vent through the wall or vertical through the roof.
Approved Vent Materials PVC, CPVC or ABS.
Minimum clearance for
Servicing 18” from top, 24” from front, 4” sides and rear.
Water Supply Pressure 150 PSI maximum allowable working pressure. Check local codes for
supply pressure.
TCO Limit Residential 118oF(87oC), Commercial 199oF(93oC).
Residential Temperature
Set Point Range 60oF (16oC) to 160oF(71oC) (approximate temperatures).
Commercial Tempera-
ture Set Point Range 80oF (27oC) to 180oF(82oC) (approximate temperatures).
Blower Temperature
Switch Normally closed, opens @ 165oF(74oC), auto reset @130oF(54oC)
Pressure Switch
UTW1 Models:
Normally open, closes on vacuum increase @ -0.68, opens on vacuum
decrease @ -0.65
U2TW Models:
Normally open, closes on vacuum increase @ -1.28, opens on vacuum
decrease @-1.25
Blower
UTW1 Models:
115VAC, 60Hz, 3.1 amps, 3000 RPM, 42 CFM @ 1.5” W.C.
U2TW Models:a,
115VAC, 60Hz, 3.1 amps, 3000 RPM, 68 CFM @ 0.4” W.C.
Specifications
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Vent Tables
Venting Specifications for:
40 Gallon—40,000 BTU/hr.
50 Gallon—40,000 BTU/hr.
60Gallon—42,000 BTU/hr.
2” Diameter (5.1 cm) PVC Vent Connector Lengths
Terminating # of Elbows Maximum Straight
Length ft (m)
Minimum Straight
Length ft (m)
Through the Wall 1 45 (13.7) 2 (0.6)
Through the Wall 2 40 (12.2) 2 (0.6)
Through the Wall 3 35 (10.7) 2 (0.6)
Through the Wall 4 30 (9.2) 2 (0.6)
Through the Roof 0 50 (15.2) 7 (2.1)
Through the Roof 1 45 (13.7) 7 (2.1)
Through the Roof 2 40 (12.2) 7 (2.1)
Through the Roof 3 35 (10.7) 7 (2.1)
Through the Roof 4 30 (9.2) 7 (2.1)
3” Diameter (7.6 cm) PVC Vent Connector Lengths
Terminating # of Elbows Maximum Straight
Length ft (m)
Minimum Straight
Length ft (m)
Through the Wall 1 115 (35.0) 10 (3.1)
Through the Wall 2 110 (33.5) 10 (3.1)
Through the Wall 3 105 (32.0) 10 (3.1)
Through the Wall 4 100 (30.5) 10 (3.1)
Through the Wall 5 95 (29.0) 10 (3.1)
Through the Roof 0 120 (36.6) 15 (4.6)
Through the Roof 1 115 (35.0) 15 (4.6)
Through the Roof 2 110 (33.5) 15 (4.6)
Through the Roof 3 105 (32.0) 15 (4.6)
Through the Roof 4 100 (30.5) 15 (4.6)
Specifications
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Vent Tables
Venting Specifications for:
48 Gallon—60,000 BTU/hr.
65 Gallon—60,000 BTU/hr.
3” Diameter (7.6 cm) PVC Vent Connector Lengths
Terminating # of Elbows Maximum Straight
Length ft (m)
Minimum Straight
Length ft (m)
Through the Wall 1 55 (16.8) 2 (0.6)
Through the Wall 2 50 (15.2) 2 (0.6)
Through the Wall 3 45 (13.7) 2 (0.6)
Through the Wall 4 40 (12.2) 2 (0.6)
Through the Roof 0 60 (18.3) 7 (2.1)
Through the Roof 1 55 (16.8) 7 (2.1)
Through the Roof 2 50 (15.2) 7 (2.1)
Through the Roof 3 45 (13.7) 7 (2.1)
4” Diameter (10.2 cm) PVC Vent Connector Lengths
Terminating # of Elbows Maximum Straight
Length ft (m)
Minimum Straight
Length ft (m)
Through the Wall 1 175 (53.3) 10 (3.1)
Through the Wall 2 170 (51.8) 10 (3.1)
Through the Wall 3 165 (50.3) 10 (3.1)
Through the Wall 4 160 (48.8) 10 (3.1)
Through the Wall 5 155 (47.2) 10 (3.1)
Through the Roof 0 180 (54.9) 15 (4.6)
Through the Roof 1 175 (53.3) 15 (4.6)
Through the Roof 2 170 (51.8) 15 (4.6)
Through the Roof 3 165 (50.3) 15 (4.6)
Through the Roof 4 160 (48.8) 15 (4.6)
Specifications
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