Bradford White TW Series User manual

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SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Through-The-Wall Gas Water Heaters
TTW Series
®
Models Covered
by This Manual:
M1TW40S*F (BN,CX)
M1TW50S*F (BN,CX)
M4TW40T*F (BN,SX)
M4TW50T*F (BN,SX)
M4TW60T*F (BN,SX)
M2TW50T*F (BN,CX)
M2TW65T*F (BN,CX)
M4XRTW50T*F (BN,SX)
M4XRTW65T*F (BN,SX)
TW450S65F (B)*(N,X)
TW465S65F (B)*(N,X)
(*) Denotes Warranty Years
Manual 238-46238A-00B

Table of Contents
Page TTW Service Procedure
Introduction 4 - - -
How to use this manual 5 - - -
Tool required for service 5 - - -
Specifications 6 - - -
Control Timings 9 - - -
Sequence of Operation 10 - - -
Troubleshooting 13 - - -
Burner Inspection, Cleaning and Replacement 17 I
Pilot Testing, Cleaning and Replacement 19 II
Pressure Switch Testing and Replacement 20 III
Blower Testing and Replacement 22 IV
Blower Temperature Switch Testing and Replacement 24 V
Gas Control & Thermal well Testing & Replacement 26 VI
Simulated Resistive Device Testing and Replacement 30 VII
Safety Circuit Voltage Trace 31 VIII
115VAC Circuit Trace 32 IX
Dip Tube inspection and Replacement 33 X
Anode Inspection and Replacement 34 XI
Flue Baffle Inspection and Replacement 35 XII
Glossary of Terms 36 - - -
Parts List 37 - - -
Page 2
2

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.
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.
FOR YOUR SAFETY
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 appliance may
create a hazard to life and property and
will nullify the warranty.
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.
IMPORTANT
Beforeproceeding, please inspectthe
water heater and its components for
possible damage. DO NOT install any
water heater with damaged components.
Ifdamage isevident then please contact
thesupplier wherethewater heater was
purchased or themanufacturer listed on
therating plate for replacement parts.
WARNING
Water heatersareheat producing appliances. To avoid
damage or injury, donot storematerials against the
water heater or vent-air intakesystem. Use proper care
to avoid unnecessary contact(especially by children) with
thewater heater and vent-air intakecomponents.
UNDER NO CIRCUMSTANCES MUST FLAMMABLE
MATERIALS, SUCH AS GASOLINE OR PAINT THINNER BE
USED OR STORED IN THE VICINITY OF THIS WATER
HEATER, VENT-AIR INTAKE SYSTEM OR IN ANY
LOCATION FROM WHICH FUMES COULD REACH THE
WATER HEATER OR VENT-AIR INTAKE SYSTEM.
WARNING
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.
CAUTION
Ifsweat fittings areto be used DO NOT apply heat to the
nipples on top of thewater heater. Sweat thetubing to
theadapter beforefitting theadapter to thewater
connections. Itisimperativethat heat isnot applied to
thenipples containing aplastic liner. WARNING
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.
WARNING
Hydrogen gas can be produced inan operating water
heater that has not had water drawnfrom thetank for a
long period of time(generally twoweeksor more).
Hydrogen gas isextremely flammable.To prevent the
possibility of injury under these conditions, we
recommend thehot water faucet to be open for several
minutes at thekitchen sink beforeyou use any electrical
appliancewhich isconnected to thehot water system. If
hydrogen ispresent, therewill be an unusual sound such
as air escaping through thepipes as hot water begins to
flow. Donot smokeor haveopen flamenear thefaucet
at thetimeitisopen.
CAUTION
Turnoff or disconnecttheelectrical power supply to the
water heater beforeservicing. Label all wires prior to
disconnection when servicing controls. Wiring errorscan
cause improper and dangerousoperation. Verify proper
operation after servicing.
Page 3
3

Page
4
Introduction
The new Bradford White TTW1, TTW2 &TW4 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 quiet operation and additional
vent lengths and 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 Thermostat/Gas Control Valve 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
&FHSR performance.
The TTW1, TTW2 &TW4 water heaters use acombustion 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. Asafety circuit consisting of apressure switch and blower
temperature switch verifies proper conditions exist for safe and reliable operation. If asituation outside
of normal operating parameters exists, the gas control diagnostic LEDwill flash acode 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. Aspecial 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 vent
models.
How the Safety System Works
During normal operation, air for combustion is drawn into the water heater through the opening 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. The air then travels up through the oriented
flame arrestor plate louvers, where the velocity of air is increased and its direction altered. The air then
mixes in anormal manner with supplied gas and is efficiently combusted, producing very low Nox
emissions.
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 in
sufficient quantity to main burner. Should be flammable vapors continue to burn, the flame arrestor
plate prevents the flames from traveling backwards and igniting vapors outside of the combustion
chamber.
4

Tools Required for Service
It is intended for this manual to be used by qualified service personal for the primary purpose of
troubleshooting and repair of the Bradford White TTW Series 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.
In some difficult to diagnose conditions, it may be necessary to isolate the heater from the vent
system to determine the problem.
Contact the Bradford White technical support group immediately if diagnosis can not be made
using the methods described in this service manual.
Page5
Manometer:Aliquid “U” tube type or adigital (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 damageor simply
not be effective to obtain certain voltageand 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. Anaccurate 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 wrenchs (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, and flashlight, 5 gallon pail.
How to Use This Manual
5

Specifications
Thermal well TCO LimitResidential 188°F (87°C), Commercial 199°F (93°C)
Residential Temperature
SetPoint Range60°F (16°C) to160°F (71°C) (Approximatetemperatures)
Blower TemperatureSwitch Normally closed, opens@ 165°F (74°C), autoreset@ 130°F (54°C).
Blower
TTW1
115VAC, 60Hz,3.1amps, 3000 RPM,42CFM@1.5" W.C.
TTW2
115VAC, 60Hz,3.1amps, 3000 RPM,68CFM@0.4" W.C.
Pressureswitch
TTW1 Models:
Normallyopen, closes on vacuum increase @ -.68,opens on vacuum decrease @ -.65
TTW2 Models:
Normallyopen, closes on vacuum increase @ -1.28,opens on vacuum decrease @ -1.25
Power supply Dedicated 115VAC, 60 Hz, 15A
Approved Gas TypeNatural or Propane. Unitmustmatch gas typesupplied.
VentingSystemPower vent through thewall or vertical through theroof
Approved Vent Materials PVC, CPVCor ABS
Gas Supply PipeMinimum 1/2"NPT(schedule 40black ironpiperecommended)
Minimum Clearance
for Servicing18" from top, 24"from front, 4"sides and rear.
Water Supply Pressure150 PSI maximum allowable workingpressure. Check local codes for supply pressure
Gas Pressure 5.0" W.C. min. for Natgas, 11.0" W.C. min. for L.P. gas, 14.0" W.C. maximum (Nat. &L.P.)
Commercial Temperature
SetPoint Range80°F (27°C) to 180°F (82°C) (Approximate temperatures)
Page6
6

Specifications
Venting Specifications for:
40 Gallon
50 Gallon
60 Gallon
Through the Wall
Terminating # of
Elbows
Maximum Straight
Length ft (m)
Minimum Straight
Length ft (m)
2" Diameter (5.1 cm) PVC Vent Connector Lengths
145 (13.7) 2 (.6)
Through the Wall 2 40 (12.2) 2(.6)
Through the Wall 3 35 (10.7)2(.6)
Through the Wall 4 30 (9.2) 2(.6)
Through the Wall
Terminating # of
Elbows
Maximum Straight
Length ft (m)
Minimum Straight
Length ft (m)
3" Diameter (7.6 cm) PVC Vent Connector Lengths
1115(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 Roof 050 (15.2) 7 (2.1)
Through the Roof 145 (13.7)7 (2.1)
Through the Roof 2 40 (12.2) 7(2.1)
Through the Roof 335 (10.7)7(2.1)
Through the Roof 0 120 (36.6)15(4.6)
Through the Roof 1115(35.0)15(4.6)
Through the Roof 2110 (33.5) 15(4.6)
Through the Roof 3105(32.0)15(4.6)
Through the Wall 5 95(29.0)10 (3.1)
Through the Roof 4100 (30.5) 18(5.5)
Vent Tables
Through the Roof 4 30 (9.2) 7(2.1)
Page 7
7

Specifications
Venting Specifications for:
48 Gallon
65 Gallon
Through the Wall
Terminating # of
Elbows
Maximum Straight
Length ft (m)
Minimum Straight
Length ft (m)
3" Diameter (7.6 cm) PVC Vent Connector Lengths
155 (16.8) 2 (.6)
Through the Wall 2 50 (15.2) 2(.6)
Through the Wall 3 45 (13.7)2(.6)
Through the Wall 4 40 (12.2) 2(.6)
Through the Wall
Terminating # of
Elbows
Maximum Straight
Length ft (m)
Minimum Straight
Length ft (m)
4" Diameter (10.2 cm) PVC Vent Connector Lengths
1175(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 Roof 060 (18.3) 7 (2.1)
Through the Roof 155 (16.8)7 (2.1)
Through the Roof 2 50 (15.2) 7(2.1)
Through the Roof 345 (13.7)7(2.1)
Through the Roof 0180 (54.9)15(4.6)
Through the Roof 1175(53.3) 15(4.6)
Through the Roof 2170 (51.8)15(4.6)
Through the Roof 3165(50.3) 15(4.6)
Through the Wall 5 155 (47.2) 12(3.6)
Through the Roof 4160 (48.8)15(4.6)
Vent Tables
Page 8
8

Control Timings
Ignition State Timing
Pre-purge15Seconds
Trial for Ignition90 Seconds
FlameStabilizationPeriod3Seconds
Inter-purge15Seconds
FlameFailureResponse Time1.5Seconds(2second. Maximum; 1second minimum.)
Post-purge15Seconds
PS FaultDelay (failed open/close)Retry after 2Minutes
Soft LockoutRetry after 5Minutes
TCO LimitLockoutIndefinite(cycle power torestart)
Simulated ResistiveLoad LockoutIndefinite(cycle power torestart)
HardwareError LockoutIndefinite(selfclearsiffaultclearsfor atleast15seconds)
Verify ResistiveDelayRetry after 2Minutes (repeats5times)
Specifications
Page9
9

Sequence of Operation
Thermostat calls for heat.
Prior to energizing blower,gas control checks safetycircuit to insure the circuit is open. Normal switch positions
in the safetycircuit are as follows:
a) Pressure switch normallyopen.
b) Blower temperature switch normallyclosed.
If the safetycircuit is closed, the control waits 4 seconds,gas control LED flashes 2 times with 3second pause.
Gas control waits 2 minutes then, blower runs for 30 seconds. This cycle repeats until safetycircuit opens.
1Start Up.
Uponpower up, the control runs a safe-start check with a typical start-up delayof 5 seconds.
2Flammable Vapor.
To assure no outputs are energizedif the “Flammable Vapor Sensor” is out of range,the control will test the
the “Flammable Vapor Sensor” for proper operating range. If the “Flammable Vapor Sensor” is out of range,the
control LED immediatelyflashes 7 times with 3second pause.
1
2Blower energizes.
Blower pre-purge period(2 seconds).
4
5Trial for pilot ignition(90seconds).
a) The gas control lights the pilot by activating spark igniter and gas flowto pilot burner.
b) If flame is not sensedwithin 90seconds,igniter and gas floware deactivated, blower will post purge and
control LED flashes 6 times with 3second pause.
6Main burner Ignition
After pilot flame is sensed, gas control activates main valve for main burner ignition. The gas control will ignore
flame and pressure switch signals for 3seconds allowing for main burner to stabilize.
Page 10
Pressure switch proves blower/vent system operation.
If the pressure switch does not close within 30 seconds,the control LED Flashes 3 times with 3second pause.
The blower runs for 30 seconds every2 minutes trying to get the pressure switch or blower temperature switch to
close. This cycle repeats as long as there is a call for heat.
3
10

Steady state operation.
DuringSteady State Operation the Control Monitors:
Thermostat temperature sensor-When set point temperature is satisfied,gas valve is shut down and
blower will post purge for 15 seconds. Control LED flashes a short flashonce every 4 seconds (idle) status
code.
Pressure switch / Blower temperature switch-Ifeither switch opens,pilot valve and main valve is shut
down. The blower continues to runs for 30 seconds attemptingto close the circuit. The control LED Flashes
3 times with3second pause.
FlameSensor-Ifflame is lost,pilot & main valve are shut down,blower runs for 15 seconds. Control attempts
to re-light pilot 4 times. Ifunsuccessful,Blower is shut down and control proceeds to 5 minute lockout. Control
re-attempts to light pilot startingat normal heatingsequence #2.
Thermostat satisfies. (Control LEDflashing once every 4seconds).
Burner off.
Blower post purge (15seconds).
9
8
10
7
Sequence of Operation
1. Flammable Vapor Sensor Fault: (For water heaters withserial numbers that begin with“K”or
later see page X.)
a) If the resistance is greater than 70,000 Ohms- the gas control immediately turns off all outputs. Control waits
and monitors resistance for 30 seconds. Ifthe 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 then once witha three 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 3000 ohms- The gas control immediately turns off all outputs and proceeds to flash
8 times then once withthree second pause. The error selfclears ifthe resistance returns to normal range for at
least 15 seconds.
2. Temperature Sensor Fault: (For water heaters withserial numbers that begin with“K”or later
see page X.)
a)Temperature sensor detected open circuit - The gas control Immediately turns off all outputs and proceeds to
flash8 times then 3 times with three second pause. The error self clears if the fault clears for at least 15 seconds.
b) Thermal well sensor not reading the sametemperature within ±5.5°F - The gas control Immediately turns off
all outputs and proceeds to flash8 times then 3 times twice withthree second pause. The error selfclears ifthe
fault clears for at least 15 seconds.
c) Water temperature in excess of TCO (Temperature Cut Off) limit - The gas control immediately turns off pilot &
main valve and proceeds to flash4 times with3second pause. Blower continues to run until gas control is reset.
To reset control,rotate knoboftemperature control to the minimum settingfor at least 6seconds before returning
to desired temperature setting.
Page 11
11

Sequence of Operation
3. Pressure Switch/Blower Temperature Fault:
a) Pressure switchclosed at start of call for heat - The gas control waits four seconds then, proceeds to flash
2 times with 3 second pause. The control waits 2 minutes and thenturns onblower for 30seconds. The blower
turns off after 30seconds and the control waits for pressure switch to open. Any time the Pressure switch opens,
the blower turns on(or stays on) and the control proceeds to waiting for pressure switch to close.
b)Pressure switchor blower temperature switchfailed to close - The gas control runs the blower for 30seconds
waiting for the pressure switch and/or blower temperature switch to close. Ifeither switch does not close in30
seconds,the blower turns off and the control flashes 3 times with 3 second pause. The gas control waits two
minutes before turning onthe blower for another 30seconds to see the circuit close. This cycle repeats as long as
there is a call for heat or until the circuit closes.
c) Pressure switchor blower temperature switchopensduring burner operation - The gas control turns off the
pilot and mainvalve,runs blower for 15 seconds (inter-purge) waiting for pressure switch and/or blower
temperature switch to close. Ifeither switch fails to close,the control proceeds as describedin3babove. Ifthe
circuit closes againby the end ofthe inter-purge,the recycle counter is incremented, ifthe recycle count has
not reachedits limit (4),another trial for ignitionbegins. Ifthe recycle count has beenreached, the gas control
turns off the blower and flashes 6 times then 2 times with 3 second pause. The gas control waits 5 minutes before
repeating ignitionsequence.
4. Trail For IgnitionFault:
a) Pressure switchopensduring trial - The gas control turns off igniter and pilot valve. The gas control proceeds
as describedin3babove. Ifthe pressure switch closes within30seconds the gas control will continue with trial for
ignitionstarting at blower pre-purge.
b) Flame Not Sensed - The gas control energizes the spark igniter attempting to light the pilot and prove flame. If
flame is not sensedwithin90 seconds,the igniter turns off, the pilot valve is closedand the gas control runs the
blower through post purge and flashes 6 times then once with 3 second pause. The control waits 5 minutes before
repeating the ignitionsequence.
5. Flame Sensing Fault:
b) Flame lost during run - The gas control turns off pilot and mainvalves,runs blower for 15 seconds (inter purge).
The gas control increments the recycle count,ifthe recycle count has not reachedits limit (4),another trial for
ignitionbegins. Ifthe recycle count has beenreached, the gas control turns off the blower and flashes 6 times
then 3 times with 3 second pause. The gas control waits 5 minutes before repeating the ignitionsequence.
c) Flame sensed out of sequence - the gas control onlylooks for pilot flame whenthe blower is running. Ifflame is
present whenthe pilot valve is not open, the gas control proceeds to wait for flame loss and flashes 5 times with 3
second pause. This continues until flame is lost,once the flame signal is lost,the control flashes 6 times then 4
times with 3 second pause. The control waits 5 minutes before repeating the ignitionsequence.
Page12
12

Shortflash, onceevery
four seconds
“Heartbeat”, alternates
bright/dim
Thermostatcalling
for heat(nofault).
Shortflash onceper
second
Weak pilotsignal
onlastcall for heat.
Twoflash, three second
pause
Pressureswitch not
working-closed
position.
Three flash, three second
pause
Pressureswitch or
blower temp.
switch notworking
-openposition.
Four flash, three second
pause
Excessive tank
temperature.
System must be
reset.
Fiveflash, three second
pause
Undesired-false
pilotflamepresent.
Troubleshooting
LED Status
Stand-by mode,
Waitingfor call for
heat(nofault).
Control Status Service
Procedure
Probable Cause
Temperaturedemand issatisfied
Normal operation.
Adjustthermostatto
temp level
Tank temperaturebelow setpoint ofthermostat.
Normal operation.
Adjust thermostat to
temp level
1. Unstablepilot.
2. Pilot tube block or restricted.
3. Oxidation buildup on pilot electrode.
4. Wire damage to pilot assemblyor bad
connection at gas valve.
1. Page 15
2-4. Page 17
1. Pressure switch tubing kinked or blocked.
2. Blocked pressure tap on switch or blower.
3. Faulty pressure switch.
Page 18
1. Vent blockage or improper vent configuration.
2. Pressure switch tubing kinked or blocked.
3. Faulty pressure switch.
4. Blower not spinning up to speed.
5. Blower temp or exhaust temp too high
6. Faulty blower temperature switch.
1. Check vent or vent tables.
2&3Page 18
4. Page 20
5&6Page 22
1. Thermal well sensor out of calibration.
2. Faulty gas control.
3. Pluming leak
1. Page 24
2. Replace gas control,
page 24
1. Pilot valve stuck in open position.Replace gas control,
page 24
None, control LED noton
or flashing
Noelectrical
power
Control power switch in“OFF”position.
Supply voltageinterrupted. Turnpower on
Page13
Observe green LED indicator on Electronic gas
control. Error flash codes are displayed with a
three second pause before repeating. Check
and repair the system as noted in the
troubleshooting table below.
GreenLED
Indicator
This chart is for water heaters with serial numbers that begin with “J”or sooner for water
heaters with serial numbers that begin with “K” or later see page 15.
13

Six-four flash, three
second pause
Undesired-false
pilot flame
sensed.
System auto
resets.
Sevenflash, three second
pause
Simulated
Resistive Device
Harness out of
specification.
Eight-oneflash, three
second pause
Simulated
Resistive Device
Harness
specification
check.
Eight-twoflash, three
second pause
Thermal well
sensor damaged
or unplugged
Eight-three flash, three
second pause
Gas valve
electronics fault
detected
LED Status Control Status Service
Procedure
Probable Cause
Pilot valve stuck in open position.Replace gas control,
page 26
Simulated resistive device out of specification.Page 28
Simulated resistive device out of specification.Page 28
1. Damage to thermal well wire.
2. Thermal well sensor resistance out of range.Page 24
1. Control needs to be reset.
2. Control is wet or physicallydamaged.
1. Interrupt power supply
2. Replace gas control,
page 26
Eight-four flash, three
second pause
Gas valve fault
detected.
1. Control needs to be reset.
2. Control is wet or physicallydamaged.
1. Interrupt power supply
2. Replace gas control,
page 26
Troubleshooting
Six-three flash, three
second pause
Pilot flame
extinguished.
System auto
resets.
1. Unstablepilot.
2. Pilot tube blocked or restricted.
3. Oxidation buildup on pilot electrode.
4. Wire damage to pilot assemblyor bad
connection at gas valve.
5. Insufficient combustion air.
6. Gas pressure is out of specification.
1. Page 15
2-4. Page 17
5. Refer to installation manual
Page14
Six-twoflash, three
second pause
Pressure switch
or blower temp
switch opened
during burner
operation.
System auto
resets.
1. Check vent or vent tables.
2&3Page 18
4. Refer to venting section of
installation manual
5. Page 20
6&7Page 22
1. Vent blockage or improper vent configuration.
2. Pressure switch tubing kinked or blocked.
3. Faulty pressure switch.
4. Vent termination being affected by wind
5. Blower not spinning up to speed.
6. Blower temp or exhaust temp too high
7. Faulty blower temperature switch.
Six-oneflash, three
second pause
Failed tolightpilot.
System autoresets.
1. Unstablepilot.
2. Pilot tube blocked or restricted.
3. Oxidation buildup on pilot electrode.
4. Wire damage to pilot assemblyor bad
connection at gas valve.
1. Page 15
2-4. Page 17
This chart is for water heaters with serial numbers that begin with “J”or sooner for water
heaters with serial numbers that begin with “K” or later see page X.
14

Troubleshooting
Observe greenLED indicator on Electronic gas
control. Error flash codes are displayed with a
three second pause before repeating. Check
and repair the system as noted in the
troubleshooting table below.
GreenLED
Indicator
Short flash, once every
fourseconds
“Heartbeat”, alternates
bright/dim
Thermostat calling
for heat (no fault).
Short flash once per
second
Weak pilot signal
on last call for heat.
Twoflash, three second
pause
Pressure switch not
working-closed
position.
Three flash, three second
pause
Pressure switch or
blower temp.
switch not working
-open position.
Fourflash, three second
pause
Excessive tank
temperature.
System must be
reset.
Fiveflash, three second
pause
Undesired-false
pilot flamepresent.
LED Status
Stand-by mode,
Waiting for call for
heat (no fault).
Control Status Service
Procedure
Probable Cause
Temperature demand is satisfied
Normal operation.
Adjust thermostat to
temp level
Tank temperature below set point of thermostat.
Normal operation.
Adjust thermostat to
temp level
1. Unstablepilot.
2. Pilot tube block or restricted.
3. Oxidation buildup on pilot electrode.
4. Wire damage to pilot assemblyor bad
connection at gas valve.
1. Page 15
2-4.Page 17
1. Pressure switch tubing kinked or blocked.
2. Blocked pressure tap on switch or blower.
3. Faulty pressure switch.
Page 18
1. Vent blockage or improper vent configuration.
2. Pressure switch tubing kinked or blocked.
3. Faulty pressure switch.
4. Blower not spinning up to speed.
5. Blower temp or exhaust temp too high
6. Faulty blower temperature switch.
1. Check vent or vent tables.
2&3Page 18
4.Page 20
5&6Page 22
1. Thermal well sensor out of calibration.
2. Faulty gas control.
3. Pluming leak
1. Page 24
2. Replacegascontrol,
page 24
1. Pilot valve stuck in open position.Replacegascontrol,
page 24
None, control LED not on
or flashing
Noelectrical
power
Control power switch in “OFF”position.
Supply voltage interrupted.Turn power on
Page 15
15

Six-four flash, three
second pause
Undesired-false
pilot flame
sensed.
System auto
resets.
Sevenflash, three second
pause
Simulated
Resistive Device
Harness out of
specification.
Eight-oneflash, three
second pause
Simulated
Resistive Device
Harness
specification
check.
Eight-twoflash, three
second pause
Temperature
sensor damaged
or unplugged
Eight-three flash, three
second pause
Gas valve
electronics fault
detected
LED Status Control Status Service
Procedure
Probable Cause
Pilot valve stuck in open position.Replace gas control,
page 26
Simulated resistive device out of specification.Page 28
Simulated resistive device out of specification.Page 28
1. Damage to temperature sensor.
2. Temperature sensor resistance out of range.Page 24
1. Control needs to be reset.
2. Control is wet or physicallydamaged.
1. Interrupt power supply
2. Replace gas control,
page 26
Eight-four flash, three
second pause
Gas valve fault
detected.
1. Control needs to be reset.
2. Control is wet or physicallydamaged.
1. Interrupt power supply
2. Replace gas control,
page 26
Six-three flash, three
second pause
Pilot flame
extinguished.
System auto
resets.
1. Unstablepilot.
2. Pilot tube blocked or restricted.
3. Oxidation buildup on pilot electrode.
4. Wire damage to pilot assemblyor bad
connection at gas valve.
5. Insufficient combustion air.
6. Gas pressure is out of specification.
1. Page 15
2-4. Page 17
5. Refer to installation manual
Six-twoflash, three
second pause
Pressure switch
or blower temp
switch opened
during burner
operation.
System auto
resets.
1. Check vent or vent tables.
2&3Page 18
4. Refer to venting section of
installation manual
5. Page 20
6&7Page 22
1. Vent blockage or improper vent configuration.
2. Pressure switch tubing kinked or blocked.
3. Faulty pressure switch.
4. Vent termination being affected by wind
5. Blower not spinning up to speed.
6. Blower temp or exhaust temp too high
7. Faulty blower temperature switch.
Six-oneflash, three
second pause
Failed tolightpilot.
System autoresets.
1. Unstablepilot.
2. Pilot tube blocked or restricted.
3. Oxidation buildup on pilot electrode.
4. Wire damage to pilot assemblyor bad
connection at gas valve.
1. Page 15
2-4. Page 17
Troubleshooting
Page16
16

Step 1.With main burner in operation, remove outer jacket door and slide inner door from left to right to open.
Step 2.To adjust for proper burning, loosen the air shutter nut, rotate the air shutter to close the opening in the
burner, then slowly rotate the air shutter open until flame becomes as blue as possible with a minimum of
yellow tips.Tighten the air shutter nut.
Too much air will cause the flame to lift off the burner ports and create noisy burner operation.
Too little air will result in soot formation.
Step 3.Close inner door and observe burner operation.Burner should operate as adjusted in step 2.If not,
repeat air shutter adjustment compensating for proper burner operation with inner door closed.
At periodic intervals (every 6 months) a visual inspection should be made of the pilot and main burner for proper
operation and to assure no debris is accumulating.
Pilot flame should be stable, some causes for an unstable pilot flame are:
a) Water heater vent is less than the allowable vent length.
b) Gas pressure is out of specification.
c) Pilot flame not fully engulfing spark/flame sensor.
Main burner should light smoothly from pilot and burn with a blue flame with a minimum of yellow tips.
Steel burner models self adjust air to gas ratio mixture and do not have an adjustable air shutter.Cast iron burner can
have the gas and air mixture properly proportioned by adjusting the air shutter on the mixer face of the main burner
(see cast iron burner adjustment below).
Main burner must be free from any debris accumulation that may effect burner operation (see burner cleaning
procedure on page 15).
Burner Inspection and Air Shutter Adjustment.
Cast Iron Burner Air Shutter Adjustment
WARNING
Inner door andburner components may be HOT when performingthis operation. Take
necessary precaution to prevent personal injury.
Air Shutter Nut
TTW SERVICE PROCEDURE I
Burner Operation Inspection,
Adjustment, Cleaning and Replacement
Air Shutter
Page17
17

Burner Cleaning
Step 1.Position gas control power switch to the
“OFF” position and unplug heater from wall
outlet.
Step 2.Turn off gas supply to water heater.
Step 3.Remove outer jacket door and slide inner door open from left to
right.
Remove Outer
door.
Slide inner door open
from left to right.
Feedline nut
Pilot tubing nut
Igniter/flame
sense wire
Step 4.Disconnect pilot tube (7/16 wrench) and
feedline (¾ wrench) from gas control.
Step 5.Disconnect igniter/flame sensor wire from gas control.
Step 6.Remove burner assembly from combustion chamber.
Step 7.Thoroughly inspect burner surface area and burner port area and
remove any loose debris.
Step 8.For cast iron burners, inspect for any debris build up inside
burner casting.
Burner
surface area
Burner
port area
Step 9.Unscrew burner from main burner
orifice.On cast iron burners, loosen
air shutter nut and unscrew feedline
from burner.
Step 10.Remove main burner orifice from
feedline (½" wrench on steel
burners, 3/8" wrench on cast iron)
inspect orifice, clean or replace if
necessary.
Step 11.Reassemble burner and reinstall into water heater.Restore gas supply
and checkfor gas leaks.
Step 12 To resume operation follow the instruction located on the lighting
instruction label or the lighting instruction located in the installation
and operating manual.
TTW SERVICE PROCEDURE I
Burner Operation Inspection,
Adjustment, Cleaning and Replacement
Page18
L.P.Main burner
orifice. Left hand
thread
Main burner
orifice
18

TTW SERVICE PROCEDURE II
Pilot testing, Cleaning and Replacement
Pilot Inspection, Testing and Replacement
Step 1.Position gas control power switch to the
“OFF” position and unplug heater from wall
outlet.
Step 2.Turn off gas supply to water heater.
Step 3.Remove outer jacket door and slide inner door open from left to
right.
Remove Outer
door.
Slide inner door open
from left to right.
Feedline nut
Pilot tubing nut
Igniter/flame
sense wire
Step 4.Disconnect pilot tube nut (7/16 wrench) and feedline nut
(¾ wrench) from gas control.
Step 5.Disconnect igniter/flame sense wire from gas control.
Step 6.Remove burner assembly from combustion chamber.
Step 7.Remove pilot assembly from feedline (¼" nut driver).
Step 8.Visually inspect igniter/flame sense wire for damage.Replace
pilot if damage is found.
Step 9.With a multi-meter set to the ohms setting, checkcontinuity
through igniter/flame sense wire.Replace pilot if no continuity.
Step 10.Visually inspect igniter/flame sense electrode for deterioration.
Replace pilot as necessary.Electrode should not be in contact
with pilot hood, If so, carefully adjust electrode to a gap
distance of 3/32" (.09) from pilot hood.
Step 11.Visually inspect igniter/flame sense electrode for oxidation
build up.Carefully clean any oxidation using very fine emery
cloth.
Step 13.Inspect pilot tubing and pilot orifice for blockage:
a) Remove ferrule nut from bottom of pilot assembly (7/16" wrench).
b) Remove pilot tube and pilot orifice.
c) Inspect pilot tubing and pilot orifice for blockage.Clean
or replace as necessary.
Step 14.Reassemble pilot and install to feedline.Reinstall burner assembly to water heater.Restore gas supply
and checkfor gas leaks.
Step 15 To resume operation follow the instruction located on the lighting instruction label or the lighting
instruction located in the installation and operating manual.
Step 12.Visually inspect pilot tubing for kinks or cracks.If damage is
found replace pilot.
Ferrule
nut
Pilot
orifice
Pilot
hood
Igniter/flame sense
electrode
Igniter/flame sense
wire
Pilot
tubing
Page19
19

TTW SERVICE PROCEDURE III
Pressure Switch Testing and
Replacement
Pressure Switch Testing WARNING
120volt potential exposure. Use caution
makingvoltage checks to avoidpersonal injury.
Step 1.Position power switch on gas control
to the “OFF” position.
Step 2.Remove the three screws (Phillips screw driver) from control access cover on blower assembly and
remove cover (see photo 1).
Step 3.Carefully remove pressure switch from blower housing (see photo 2)
2
Use amulti-meter set to the
ohms setting.With blower off,
check across pressure
switch terminals.
Are switch contacts open?
(no electrical continuity)
Check tubing and pressure tap
on switch for blockage.
Is there blockage?
Replace switch
(see page19)
Position gas valve power
switch to the “ON” position
and adjust thermostat
to call for heat,
this will start the blower.
Check with multi-meter, do
pressure switch contacts close
with blower running?
1
With steps 1,2 &3 complete,
disconnect wire leads from
pressure switch.
Y
N
Y
N
Switch contacts are OK.
See safety circuit trace
(page29)
Is vent
system
blocked
NSee blower testing
(page20)
Is blower OK?
Clear blockage
Y
N
Y
N
Correct blower
problem.
Pressure Switch
Slide pressure switch in direction of
arrow while tilting slightly away
from blower housing.
Is vent system length
within vent table
specifications
listed on pages 7&8
Y
Reconfigure vent
system to be
compliant with
vent tables.
N
Y
Pressure switch
wire leads
Page20
Check tubing and
pressure tap on
switch for blockage.
Is there blockage?
N
Y
20