Bradford-White U4TW40T'FRN User Manual

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TTW® Eco-Defender

Residential Ultra Low NOx Gas Water Heaters

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

U4TW40T*FRN

U4TW50T*FRN

U4TW60T*FRN

U2TW50T*FRN

U2TW65T*FRN

UTW450S60FR*N

UTW465S60FR*N

(*) Denotes Warranty Years

(Model Shown: U-4-TW-40T6FRN)

Manual 238-48509-00A

Save this manual for future reference

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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x
x
x

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:

Do not try to light any appliance

Do not touch any electrical switch; do not use any phone in your building

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.

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.

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.

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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Introduction

The Bradford White ECO-DEFENDERSafety System®

The Bradford White ECO-DEFENDERSafety 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 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 WhiteECO-DEFENDERSafety System.

Introduction

The new Bradford White TTW ECO-DEFENDERwater 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, quiet operation, additional vent lengths, Bradford WhiteECO-DEFENDERSafety System ® and Ultra Low NOx emissions.

Spark-to-Pilot Ignition System - Employing thespark-to-pilotignition 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.

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 and FHSR performance.

The TTW1 (U1TW & U4TW), TTW2 (U2TW) & UTW4 water heaters use a combustion system were 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

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How to Use this Manual

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-resistantcombustion 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.

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Tools Required

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-ampsand ohms.

Electronic Probes: In some cases, standardmulti-meterprobes will damage or simply not be effective to obtain certain voltage and ohm reading. It will be necessary to have special electronic “pin” typemulti-meterprobes. 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 number239-45991-00.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.

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Specifications

 

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

18” from top, 24” from front, 4” sides and rear.

 

 

Servicing

 

 

 

 

 

 

 

 

 

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

60oF (16oC) to 160oF (71oC) (approximate temperatures).

 

 

Set Point Range

 

 

 

Commercial Tempera-

80oF (27oC) to 180oF (82oC) (approximate temperatures).

 

 

ture Set Point Range

 

 

 

 

 

 

 

 

 

Blower Temperature

Normally closed, opens @ 165oF (74oC), auto reset @130oF (54oC)

 

 

Switch

 

 

 

 

 

 

 

 

 

 

UTW1 Models:

 

 

 

Normally open, closes on vacuum increase @ -0.68,opens on vacuum

 

 

 

decrease @ -0.65

 

 

 

U4TW Models:

 

 

Pressure Switch

Normally open, closes on vacuum increase @ -0.83,opens on vacuum

 

 

 

 

 

 

decrease @ -0.80

 

 

 

U2TW & UTW4 Models:

 

 

 

Normally open, closes on vacuum increase @ -1.28,opens on vacuum

 

 

 

decrease @-1.25

 

 

 

 

 

 

 

U1TW & U4TW Models:

 

 

Blower

115VAC, 60Hz, 3.1 amps, 3000 RPM, 42 CFM @ 1.5” W.C.

 

 

U2TW & UTW4 Models:

 

 

 

 

 

 

115VAC, 60Hz, 3.1 amps, 3000 RPM, 68 CFM @ 0.4” W.C.

 

 

 

 

 

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Specifications

Vent Tables

Venting Specifications for:

40 Gallon

50 Gallon

60 Gallon

2” Diameter (5.1 cm) PVC Vent Connector Lengths

Terminating

# of Elbows

Maximum Straight

Minimum Straight

Length ft (m)

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

Minimum Straight

Length ft (m)

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)

 

 

 

 

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Specifications

Vent Tables

Venting Specifications for:

48 Gallon

65 Gallon

3” Diameter (7.6 cm) PVC Vent Connector Lengths

Terminating

# of Elbows

Maximum Straight

Minimum Straight

Length ft (m)

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

Minimum Straight

Length ft (m)

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)

 

 

 

 

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