Bradford White U65L155E N Series User manual

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Manual 238-50129-00A
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
U65L155E*N (A)
U65L199E*N (A)
U65L270E*N (A)
U100L199E*N (A)
U100L270E*N (A)
U100L300E*N (A)
U100L399E*N (A)
(*) Denotes Warranty Years
Gas Water Heaters
Ultra Low NOx Atmospheric Vent

Table of Contents
The Bradford White
2
Page Service Procedure
Introduction 3 - - -
How to use this manual 4 - - -
Tool required for service 4 - - -
Features 5 - - -
Specifications 6 - - -
Sequence of Operation 8 - - -
Troubleshooting 10 - - -
Thermostat Circuit, Testing & Replacement 27 I
Combustion System Testing and Replacement 31 II
Burner Tube Inspection & Replacement 35 III
Gas Valve Replacement 37 IV
Blower Testing and Replacement 38 V
Flame Sensor Testing and Replacement 40 VI
Spark Rod Replacement 42 VII
Ignition Module/Control Board Replacement 43 VIII
Transformer Replacement 44 IX
Anode Inspection and Replacement 45 X
Circulator Assembly Inspection and Replacement 46 XI
Blocked Vent Switch Inspection and Replacement 47 XII
Damper Inspection and Replacement 48 XIII
Heater Service Report 49 - - -
Parts List 50 - - -
Glossary of Terms 53 - - -
2

Introduction
The Bradford Ultra Low NOx Atmospheric Vent Water Heater uses a ultra low Nox
premix power burner located at the top of the water heater to direct a turbulent
flame down into the combustion chamber. This turbulence causes a thorough
mixing of gas and air for optimum combustion. The combustion gases then travel
through a single pass flue system keeping the gases moving at a high velocity.
The combination of high turbulence and velocity results in an optimum transfer of
heat from the flue gases into the water.
Burner operation is controlled using an electronic ignition module. The module
monitors the status of the electronic thermostat, blocked vent limit switch,
circulator flow switch, flame sensor to control output voltage to blower motor, spark
rod and gas valve. The module contains programming which determines the
sequence of operation and timings for purge periods, trial for ignition, flame
sensing and lockout. The module will also provide diagnostic information to help in
determining the cause of system lockouts.
The contents in this manual are detailed informational tools to assist in the proper
diagnosis of the Ultra Low NOx Atmospheric Vent Water Heater operational faults.
Please read this service manual completely and record as much information
regarding the Ultra Low NOx Atmospheric Vent Water Heater operation and
installation specifics related to any concerns.
The Bradford White Ultra Low NOx Atmospheric Vent Water Heater is designed to
deliver a remarkable amount of hot water at 84% efficient in a quiet running unit
with a low vent connection that allows for installation existing locations. Several
technologically advanced design features are incorporated in the design that will
require additional knowledge on the part of the qualified service provider. The
information in this manual will instruct service and maintenance professionals on
the function, proper diagnosis and repair of The Bradford White Ultra Low NOx
Atmospheric Vent Water Heater.
3
3

Tools Required for Service
Itis intended for this manual to be used by qualified service personal for the primary purpose
of troubleshooting analysis and repair of the Bradford White Ultra Low NOX Atmospheric
Vent Water Heater. Understanding the sequence of operation section of this manual will
contribute greatlyto troubleshooting this product.
A“Service Report” is shown towards the end of this manual. Completing this form will assist
in the troubleshooting efforts. Shouldyou need to call for technical support, please provide
the information shown on this form to the support technician to insure accurate
troubleshooting.
Troubleshooting begins with “System Observation” to determine failure mode as indicated by
the LED status of the ignition module. Troubleshooting continues with “Failure Modes and
Probablecause” directing the service provider to aseries of test procedures to determine
root cause of failure. Component replacement procedures directlyfollow the test procedures
for agiven component.
Contact Technical support immediatelyif diagnosis is not determined using the methods
described in this service manual.
Manometer: Twotypes available, aliquid “U” tube typeor adigital (magna-helic)
type. Thisdeviceisused to measuregas and/or air pressures and
vacuum.
Multi-Meter: A digital typeisstrongly recommended. Thisdeviceisused to measure
electrical values. Themeter you selectmust havethecapability to
measurevolts AC, volts DC, Amps, micro-ampsand ohms.
Thermometer: Used to measurewater temperature. Anaccurate thermometer is
recommended.
Water PressureGage:Used to measurewater supply pressure. Also used to determine tank
pressureby adapting to thedrainvalveof theheater.
Jumper Leads:Alength of wire(12" min.) with alligator clip at both ends.
VariousHand Tools: Pipewrench, channel locks, open end wrench set, 12" crescent wrench,
Allen wrench set, torx bitset, screw drivers(common & Phillips), long
reach (12") magnetic tip Phillipshead screw driver #2tip, ¼" nutdriver,
pliers(common & needle nose), socket set including a1-1/16 deep well
socket, wirecutters, wirestrippers, wirecrimpers, torpedolevel, small
shop sac, step ladder, and flashlight.
4
4

Attractive digital water heater display on control panel for setting and displaying the
temperature setpoint. Pressing temperature UP and DOWN buttons changes the
temperature setpoint. Same water heater display used on all models. Temperature
format may be displayed in °F or °C.
Singlecontrol board with plug in wiring controlstemperature, ignition, and blower
operation.
Reduced number of parts for servicing and wiring.
Plug in wiring reduces chance of miswirng.
Burner ignition with direct spark ignition - Ahigh voltage spark jumps from the spark rod to
the burner surface to ignite the gas. Eliminates burned out hot surface igniter
replacements.
Water heater display will show diagnostic codes in the event the water heater needs
servicing. Aids in diagnosing and servicing the water heater.
Water heater display can show previous error code history to further aid in servicing the
water heater.
Features of Honeywell Integrated Control System
5
5

6
Model Description
1
st
Hour
Delivery at
100°F Rise
(Gal.)
A
Floor to
Top of
Vent
(in.)
B
Vent
Dia.
(in)
C
Floor
to
Cold
Water
Conn.
(in)
D
Floor
to
T& P
(in)
E
Floor
to Hot
Water
Conn.
(in)
F
Floor to
Top of
Water
Heater
(in)
G
Floor
to Gas
Conn.
(in)
Water
Conn.
Dia.
(in.)
Gas
Conn.
Dia.
(in.)
Relief
Valve
(in.)
Model Number Capacity
(GAL)
Input BTU/Hr.
NAT.
U65L155E3N(A) 65 155,000 203 56 ¼ 6 10 ½ 37 39 ½ 61 581 ½ ¾ ¾
U65L199E3N(A) 65 199,999 249 56 ¼ 6 10 ½ 37 39 ½ 61 581 ½ ¾ ¾
U65L270E3N(A) 65 270,000 320 56 ¼ 6 10 ½ 37 39 ½ 61 581 ½ ¾ ¾
U100L199E3N(A) 100 199,999 27456 ¼ 6 10 ½ 53 ¼ 55 ¾ 77 ¼ 74½ 1 ½ ¾ ¾
U100L270E3N(A) 100 270,000 345 56 ¼ 6 10 ½ 53 ¼ 55 ¾ 77 ¼ 74½ 1 ½ ¾ 1
U100L300E3N(A) 100 300,000 375 57 ¼ 7 10 ½ 53 ¼ 55 ¾ 77 ¼ 74½ 1 ½ ¾ 1
U100L399E3N(A) 100 399,999 477 57 ¼ 810 ½ 53 ¼ 55 ¾ 77 ¼ 74½ 1 ½ 1 1
Dimensional Layout
6

Honeywell Integrated Control System
7
Power supply Dedicated 120 VAC, 60 Hz,15A
Thermostat Sensor 11,900 Ohms @ 70°F, ECO opens @ 207°FMax. Redundant sensor for ECO.Sensor insidewell for easy
replacement of sensor.
SparkRod Igniter 0.22" nominal gap to the burner surface.
Flame Sensor Output Minimum 1microamp, Typical range 5to 30 microamps.
Control Display
Digital display, 24 volts. TemperatureRange: 70-180 deg. F. Used to set tank temperature(deg. For
deg. C), show operating status, Display error codes, error codehistory, limit maximum setpoint
temperature.
Control Board Operates from 24 volt from transformer.Controls tank temperature, ignition functions, combustion
blower.See ignition timings in sequence of operation for Integrated Control.
Gas Valve Negative regulation, 24 VAC, ½" PSI max.,4.5" W.C. Minimum running inlet.
Transformer120VAC primary, 24VAC secondary, 40VA.
Blocked Vent Safety Switch Normally closed,opens @ 240°F, manual reset.
Blower120VAC, 60Hz,.6-1 amps, 6400 RPM.
Approved Gas Type Natural gas only. Gas supply must match the gas type listed on the water
heater rating label.
Venting System
Atmospherically Vented,Type B venting system or approved chimney. Follow
current National Fuel Gas Coderequirements or in Canada, the Natural Gas
Installation Code.
Gas Supply Minimum ¾”NPT for 300,000 BTU’s/hr.and below. Minimum 1" NPT for 399,999 BTU’s/hr.
(schedule 40 black iron pipe recommended)
Minimum Clearance
for Servicing
4" from the top, 0"from the front, 4" from the exhaust vent side, 12" from the circulation loop side, 0"
from the rear.
Maximum Water Supply
Pressure150 PSI
Gas Pressure (Nat.)14.0"W.C. maximum static, 4.5" W.C. minimum running (recommend 7.0"W.C. min running)
Combustion Levels CO2: 10-11%,CO:less then 0.04percent (400 PPM) air free
Circulator Flow Switch 24 VAC, normally open, closes when circulator is operational
Circulator120VAC ,60Hz,.76-1 amps, 3250 PRM
7

For models with Honeywell Integrated Control
System w/ Direct Spark Ignition
Thermostat callsfor heat.
Combustion blower &circulator start whilethe damper opens.
Blower pre-purge period of 30 seconds.
Trial for Ignition. (5 seconds, 3trials).
Flame establishing period (3 seconds), gas valve opens, sparks from spark rod to burner surface to ignite
the gas.
Burner on, flame proving period (2 seconds). Requires aminimum of 0.8microamp through flame sense
rod to prove flame.
Ifeither blocked vent safety switch contacts (normallyclosed) or circulator flow switch and damper contacts
(normallyopen) remain open after being energized, then the ignition sequence will not start and an error
code 29 (Safety switch circuit failed to close or open) will be shown on the display.
Steady State Operation: Burner continues to operate until:
Thermostat circuit opens, gas valve closes, blower continues to operate for 30 second post-purge period.
Ifthe normallyclosed blocked vent safety switch opens, the gas valve closes, the blower post-purges, then
shuts off with error code 26 displayed in alockout condition.
Thermostat satisfied.
Gas valve closes, burner extinguished.
Blower post purge for 30 seconds.
1
2
3
5
6
7
8
4
8
8

For models with Honeywell Integrated Control
System w/ Direct Spark Ignition
The system will go into lock out mode for the following reasons:
1.ERROR CODE 26
Ifthe blocked vent safety switch mounted on the draft hood shouldopen, the gas valve will close, the blower
will post-purge and error code 26 will appear on the display. The lockout condition will reset once the problem is
corrected and the switch reset. Refer to “Vent Safety Switch Testing and Replacement” in this Service Manual.
2.ERROR CODE 29
Ifthe circulator flow switch or the damper contacts fail to open or close in the normal sequence of operation, the
gas valve closes, and error code 29 will appear on the control display. When the condition is corrected, the error
code will disappear and the water heater will resume normal operation. Noresetting of the control display is
needed for resetting this error code.
3.ERROR CODE 62 or 63
Control board will go into “Soft Lockout” if the main burner cannot be lit or failsto prove flame after 3ignition trials.
The water heater display indicates alockout condition by showing an error code number (62 or 63) with “Service
Needed” in the control display window. Refer to error codes in the diagnostic section of this Service Manual. Ina
“Soft Lockout” condition, the control will wait for 60 minutes and then make 3more attempts to light the main
burners. Soft lockout reset is accomplished by depressing the lower right button under “Reset” for 3seconds.
4. ERROR CODE 65
Ifthe top of the tank shouldexceed 207°F,then the high limit control will shut off the burner and the water heater
will go into a“Hard Lockout”. Error code 65 will be shown in the water heater display. The control can onlybe
reset in the “Service Mode”, which is detailed in the “Troubleshooting” section of this Service Manual.
Lockout Conditions (Complete list of error codes is listed on the unit)
CONNECTION/WIRING DIAGRAM
9
9

System Observation
For modelswithDirect SparkIgnition
Water Heater Fault: Water heater does not operate
Display Error Code: Water heater display does not operate - blankdisplay
Checkmain power supplyto water
heater - fuse, circuit breaker, plug
receptacle, line cord or wiring to water
heater.
Check to make sure switch on front of
control panel is in the ON position
Verify Primary voltage at the
control board.
Verify Secondary voltage at the control
board.
Check wires for proper termination
to control display.
Are wire terminations connected
properlyto control display?
N
Y
CAUTION
Use caution not to damage connectors when
making voltage measurements or jumping terminals
WARNING
120 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
Is24VAC present between
RED and BLACK wire pin
connections on the back of
Control Display?
123
8
6
5
4
3
1
12
1
4
1
3
3
2
1
1
5
3
P2 P4P5 P7P3
CONTROL BOARD
P10P9J1
Refer to Control Board illustration.
Voltage at primary pins P2(1)&P2(3)
will be 110-120. Ifnot, check Line In
pins P3(1)&P3(4). Check line cord with
voltmeter. Replace line cord if
defective.
Refer to Control Board illustration. Voltage at
secondary pins P4(1)&P4(2)will be 24VAC.
Ifnot, check transformer. Replace
transformer or wire harness.
Does water heater display operate?
Does the combustion blower start to
operate? Increase thermostat setting if
tank is warm.
Is24VAC present between E-COM
screw terminalsP9(2)&P9(3)on
the Control Board.
Y
N
Replace Control
Display.
N
Display Operates - See next
page
10
Y
Make proper wire
terminations
N
Replace
Control Board
YCheck wire
harness for
proper continuity
Transformer
Top terminalsare 24VAC (Blue and Yellow/Green)
Bottom terminalsare 120VAC (Black and White)
Y
Y
Y
Y
N
N
10