Bradford White M1TW50S*FCX, M1TW40S*FBN, M1TW40S*FCX, M1TW50S*FBN, M4TW40T*FBN Service 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

2

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

WARNING: If the information in these instructions is

3

not followed exactly, a fire or explosion may result
causing property damage, personal injury, or death.

Incorrect operation of this appliance may

CAUTION

create a hazard to life and property and

will nullify the warranty.

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.

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.

WARNING

Water heaters are heat producing appliances. To avoid

damage or injury, do not store materials against the

water heater or vent-air intake system. Use proper care

to avoid unnecessary contac

the water heater and vent-air intake components.

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.

t (especially by children) with

CAUTION

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 appli

the nipples containing a plastic liner.

ed to

WARNING

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 extr

possibility of injury under these conditions, we

recommend the hot water faucet to be open for several
minutes at the kitchen sink before you use any electrical

app

liance 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 sm

emely flammable. To prevent the

oke or have open flame near the faucet

at the time it is open.

Do not store or use gasoline or other

flammable, combustible, or corrosive

vapors and liquids in the vicinity of this

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 supplie
purchased or the manufacturer listed on

the rating plate for replacement parts.

DANGER

or any other appliance.

IMPORTANT

r where the water heater was

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.

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.

CAUTION

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 d

operation after servicing.

angerous operation. Verify proper

Page 3

4

Introduction

4

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 spar
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

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 a combustion system
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
temperature switch verifies proper conditions exist for safe and reliable operation. 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
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.

k to pilot ignition system promotes reliable and

significantly reduced for both interior and

where flue gases are combined with

pressure switch and blower

and enhance service efficiency. To

Please read the service manual
models.

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 a normal 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
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.

completely before attempting service on this new series of power vent

How the Safety System Works

flowing into the

Page

How to Use This Manual

5

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.

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.

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.

Page 5

Specifications

6

Power supply Dedicated 115VAC, 60 Hz, 15A

Gas Supply Pipe Minimum 1/2" NPT (schedule 40 black iron pipe recommended)

Approved Gas Type Natural or Propane. Unit must match gas type supplied.

Gas Pressure 5.0" W.C. min. for Nat gas, 11.0" W.C. min. for L.P. gas, 14.0" W.C. maximum (Nat. & L.P.)

Venting System Power vent through the wall or vertical through the roof

Approved Vent Materials PVC, CPVC or ABS

Minimum Clearance

for Servicing

Water Supply Pressure 150 PSI maximum allowable working pressure. Check local codes for supply pressure

Thermal well TCO Limit Residential 188°F (87°C), Commercial 199°F (93°C)

Residential Temperature

Set Point Range

Commercial Temperature

Set Point Range

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

60°F (16°C) to 160°F (71°C) (Approximate temperatures)

80°F (27°C) to 180°F (82°C) (Approximate temperatures)

Blower Temperature Switch Normally closed, opens @ 165°F (74°C), auto reset @ 130°F (54°C).

TTW1 Models:
Normally open, closes on vacuum increase @ -.68, opens on vacuum decrease @ -.65

Pressure switch

TTW2 Models:
Normally open, closes on vacuum increase @ -1.28, opens on vacuum decrease @ -1.25

TTW1
115VAC, 60Hz, 3.1 amps, 3000 RPM, 42CFM@1.5" W.C.

Blower

TTW2
115VAC, 60Hz, 3.1 amps, 3000 RPM, 68CFM@0.4" W.C.

Page 6

Venting Specifications for:

7

40 Gallon

50 Gallon
60 Gallon

Specifications

Vent Tables

2" Diameter (5.1 cm) PVC Vent Connector Lengths

Terminating

Through the Wall

# of

Elbows

1 45 (13.7) 2 (.6)

Maximum Straight

Length ft (m)

Minimum Straight

Length ft (m)

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 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

Through the Wall

# of

Elbows

1 115 (35.0) 10 (3.1)

Maximum Straight

Length ft (m)

Minimum Straight

Length ft (m)

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) 18 (5.5)

Page 7

Venting Specifications for:

8

48 Gallon

65 Gallon

Specifications

Vent Tables

3" Diameter (7.6 cm) PVC Vent Connector Lengths

Terminating

Through the Wall

# of

Elbows

1 55 (16.8) 2 (.6)

Maximum Straight

Length ft (m)

Minimum Straight

Length ft (m)

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 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

Through the Wall

# of

Elbows

1 175 (53.3) 10 (3.1)

Maximum Straight

Length ft (m)

Minimum Straight

Length ft (m)

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) 12 (3.6)

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)

Page 8

Control Timings

9

Ignition State Timing

Pre-purge 15 Seconds

Trial for Ignition 90 Seconds

Flame Stabilization Period 3 Seconds

Inter-purge 15 Seconds

Flame Failure Response Time 1.5 Seconds (2 second. Maximum; 1 second minimum.)

Post-purge 15 Seconds

PS Fault Delay (failed open/close) Retry after 2 Minutes

Soft Lockout Retry after 5 Minutes

TCO Limit Lockout Indefinite (cycle power to restart)

Verify Resistive Delay Retry after 2 Minutes (repeats 5 times)

Simulated Resistive Load Lockout Indefinite (cycle power to restart)

Specifications

Hardware Error Lockout Indefinite (self clears if fault clears for at least 15 seconds)

Page 9

Sequence of Operation

10

1

Start Up.

Upon power up, the control runs a safe-start check with a typical start-up delay of 5 seconds.

2

Flammable Vapor.

To assure no outputs are energized if 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 immediately flashes 7 times with 3 second pause.

1

Thermostat calls for heat.

Prior to energizing blower, gas control checks safety circuit to insure the circuit is open. 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 co

ntrol waits 4 seconds, gas control LED flashes 2 times with 3 second pause.

Gas control waits 2 minutes then, blower runs for 30 seconds. This cycle repeats until safety circuit opens.

2

Blower energizes.

3

Pressure switch proves blower/vent system operation.

If the pressure switch does not close within 30 seconds, the control LED Flashes 3 times with 3 second pause.
The blower runs for 30 seconds every 2 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.

4

Blower pre-purge period (2 seconds).

5

Trial for pilot ignition (90 seconds).

a) The gas control lights the pilot by activating spark igniter and gas flow to pilot burner.
b) If flame is not sensed within 90 seconds, igniter and gas flow are deactivated, blower will post purge and

control LED flashes 6 times with 3 second pause.

6

Main 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 3 seconds allowing for main burner to stabilize.

Page 10

Steady state operation.

11

7

8

Thermostat satisfies. (Control LED flashing once every 4 seconds).

9

Burner off.

During Steady 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 flash once every 4 seconds (idle) status
code.

Pressure switch / Blower temperature switch- If either switch opens, pilot valve and main valve is shut
down. The blower continues to runs for 30 seconds attempting to close the circuit. The control LED Flashes
3 times with 3 second pause.

Flame Sensor- If flame is lost, pilot & main valve are shut down, blower runs for 15 seconds. Control attempts
to re-light pilot 4 times. If unsuccessful, Blower is shut down and control proceeds to 5 minute lockout. Control
re-attempts to light pilot starting at normal heating sequence #2.

Sequence of Operation

10

Blower post purge (15 seconds).

1. Flammable Vapor Sensor Fault: (For water heaters with serial 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. 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 then once

with a 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 with three second pause. The error self clears if t

he resistance returns to normal range for at

least 15 seconds.

2. Temperature Sensor Fault: (For water heaters with serial 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

flash 8 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 same temperature within ±5.5 °F - The gas control Immediately turns off

all outputs and proceeds to flash 8 times then 3 times twice with three second pause.
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 flash 4 times with 3 second pause. Blower continues to run until gas control is reset.
To reset control, rotate knob of temperature control to the minimum setting for at least 6 seconds before returning
to desired temperature setting.

The error self clears if the

Page 11

Sequence of Operation

12

3. Pressure Switch/Blower Temperature Fault:

a) Pressure switch closed 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 then turns on blower for 30 seconds. The blower
turns off after 30 seconds 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 switch or blower temperature switch failed to close - The gas control runs the blower for 30 seconds

waiting for the pressure switch and/or blower temperature switch to close. If either switch does not close in 30
seconds, the blower turns off and the control flashes 3 times with 3 second pause. The gas control waits two
minutes before turning on the blower for another 30 seconds to see the circuit close. This cycle repeats as long
there is a call for heat or until the circuit closes.

c) Pressure switch or blower temperature switch opens during burner operation - The gas control turns off the

pilot and main valve, runs blower for 15 seconds (inter-purge) waiting for pressure switch and/or blower
temperature switch to close. If either switch fails to close, the control proceeds as described in 3b above. If the
circuit closes again by the end of the i
not reached its limit (4), another trial for ignition begins. If the recycle count has been reached, 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 ignition sequence.

nter-purge, the recycle counter is incremented, if the recycle count has

as

4. Trail For Ignition Fault:

a) Pressure switch opens during trial - The gas control turns off igniter and pilot valve. The gas control proceeds

as described in 3b above. If the pressure switch closes within 30 seconds the gas control will continue with trial for
ignition starting 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 sensed within 90 seconds, the igniter turns off, the pilot valve is closed and 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 ignition sequence.

5. Flame Sensing Fault:

b) Flame lost during run - The gas control turns off pilot and main valves, runs blower for 15 seconds (inter purge).

The gas control increments the recycle count, if the recycle count has not reached its limit (4), another trial for
ignition begins. If the recycle count has been reached, the gas control turns off the blower and
then 3 times with 3 second pause. The gas control waits 5 minutes before repeating the ignition sequence.

c) Flame sensed out of sequence - the gas control only looks for pilot flame when the blower is running. If flame is

present when the 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,
times with 3 second pause. The control waits 5 minutes before repeating the ignition sequence.

once the flame signal is lost, the control flashes 6 times then 4

flashes 6 times

Page 12

Troubleshooting

13

Green LED

Indicator

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.

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.

LED Status

None, control LED not on
or flashing

Short flash, once every
four seconds

“Heartbeat”, alternates
bright/dim

Control Status

No electrical
power

Stand-by mode,
Waiting for call for
heat (no fault).

Thermostat calling
for heat (no fault).

Probable Cause

Control power switch in “OFF” position.
Supply voltage interrupted.

Temperature demand is satisfied

Tank temperature below set point of thermostat.

Service

Procedure

Turn power on

Normal operation.

Adjust thermostat to

temp level

Normal operation.

Adjust thermostat to

temp level

Short flash once per
second

Two flash, three second
pause

Three flash, three second

pause

Four flash, three second
pause

Five flash, three second
pause

Weak pilot signal
on last call for heat.

Pressure switch not
working-closed
position.

Pressure switch or
blower temp.

switch not working

-open position.

Excessive tank
temperature.
System must be
reset.

Undesired-false
pilot flame present.

1. Unstable pilot.

2. Pilot tube block or restricted.

3. Oxidation build up on pilot electrode.

4. Wire damage to pilot assembly or bad

connection at gas valve.

1. Pressure switch tubing kinked or blocked.

2. Blocked pressure tap on switch or blower.

3. Faulty pressure switch.

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. Thermal well sensor out of calibration.

2. Faulty gas control.

3. Pluming leak

1. Pilot valve stuck in open position.

1. Page 15

2-4. Page 17

Page 18

1. Check vent or vent tables.

2 & 3 Page 18

4. Page 20

5 & 6 Page 22

1. Page 24

2. Replace gas control,
page 24

Replace gas control,
page 24

Page 13

Troubleshooting

14

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.

LED Status Control Status

Six-one flash, three
second pause

Six-two flash, three
second pause

Six-three flash, three
second pause

Six-four flash, three
second pause

Seven flash, three second
pause

Eight-one flash, three
second pause

Eight-two flash, three
second pause

Eight-three flash, three
second pause

Failed to light pilot.
System auto resets.

Pressure switch
or blower temp
switch opened
during burner
operation.
System auto
resets.

Pilot flame
extinguished.
System auto
resets.

Undesired-false
pilot flame
sensed.
System auto
resets.

Simulated
Resistive Device
Harness out of
specification.

Simulated
Resistive Device
Harness
specification
check.

Thermal well
sensor damaged
or unplugged

Gas valve
electronics fault
detected

Probable Cause

1. Unstable pilot.

2. Pilot tube blocked or restricted.

3. Oxidation build up on pilot electrode.

4. Wire damage to pilot assembly or bad

Procedure

1. Page 15

2-4. Page 17

connection at gas valve.

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.

1. Check vent or vent tables.

2 & 3 Page 18

4. Refer to venting section of
installation manual

5. Page 20

6 & 7 Page 22

1. Unstable pilot.

2. Pilot tube blocked or restricted.

3. Oxidation build up on pilot electrode.

4. Wire damage to pilot assembly or bad
connection at gas valve.

1. Page 15

2-4. Page 17

5. Refer to installation manual

5. Insufficient combustion air.

6. Gas pressure is out of specification.

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.

1. Control needs to be reset.

2. Control is wet or physically damaged.

Page 24

1. Interrupt power supply

2. Replace gas control,
page 26

Service

Eight-four flash, three
second pause

Gas valve fault
detected.

1. Control needs to be reset.

2. Control is wet or physically damaged.

1. Interrupt power supply

2. Replace gas control,
page 26

Page 14

Observe green LED indicator on Electronic gas

15

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.

Troubleshooting

Green LED

Indicator

LED Status

None, control LED not on
or flashing

Short flash, once every
four seconds

“Heartbeat”, alternates
bright/dim

Short flash once per
second

Two flash, three second
pause

Three flash, three second

pause

Four flash, three second
pause

Control Status

No electrical
power

Stand-by mode,
Waiting for call for
heat (no fault).

Thermostat calling
for heat (no fault).

Weak pilot signal
on last call for heat.

Pressure switch not

working-closed
position.

Pressure switch or
blower temp.
switch not working

-open position.

Excessive tank
temperature.
System must be
reset.

Probable Cause

Control power switch in “OFF” position.
Supply voltage interrupted.

Temperature demand is satisfied

Tank temperature below set point of thermostat.

1. Unstable pilot.

2. Pilot tube block or restricted.

3. Oxidation build up on pilot electrode.

4. Wire damage to pilot assembly or bad

connection at gas valve.

1. Pressure switch tubing kinked or blocked.

2. Blocked pressure tap on switch or blower.

3. Faulty pressure switch.

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. Thermal well sensor out of calibration.

2. Faulty gas control.

3. Pluming leak

Service

Procedure

Turn power on

Normal operation.

Adjust thermostat to

temp level

Normal operation.

Adjust thermostat to

temp level

1. Page 15

2-4. Page 17

Page 18

1. Check vent or vent tables.

2 & 3 Page 18

4. Page 20

5 & 6 Page 22

1. Page 24

2. Replace gas control,
page 24

Five flash, three second
pause

Undesired-false
pilot flame present.

1. Pilot valve stuck in open position.

Replace gas control,
page 24

Page 15

Troubleshooting

16

LED Status Control Status

Six-one flash, three
second pause

Six-two flash, three
second pause

Six-three flash, three
second pause

Six-four flash, three
second pause

Seven flash, three second
pause

Eight-one flash, three
second pause

Eight-two flash, three
second pause

Eight-three flash, three
second pause

Failed to light pilot.
System auto resets.

Pressure switch
or blower temp
switch opened
during burner
operation.
System auto
resets.

Pilot flame
extinguished.
System auto
resets.

Undesired-false
pilot flame
sensed.
System auto
resets.

Simulated
Resistive Device
Harness out of
specification.

Simulated
Resistive Device
Harness
specification
check.

Temperature
sensor damaged
or unplugged

Gas valve
electronics fault
detected

Probable Cause

1. Unstable pilot.

2. Pilot tube blocked or restricted.

3. Oxidation build up on pilot electrode.

4. Wire damage to pilot assembly or bad

Procedure

1. Page 15

2-4. Page 17

connection at gas valve.

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.

1. Check vent or vent tables.

2 & 3 Page 18

4. Refer to venting section of
installation manual

5. Page 20

6 & 7 Page 22

1. Unstable pilot.

2. Pilot tube blocked or restricted.

3. Oxidation build up on pilot electrode.

4. Wire damage to pilot assembly or bad
connection at gas valve.

1. Page 15

2-4. Page 17

5. Refer to installation manual

5. Insufficient combustion air.

6. Gas pressure is out of specification.

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.

1. Control needs to be reset.

2. Control is wet or physically damaged.

Page 24

1. Interrupt power supply

2. Replace gas control,
page 26

Service

Eight-four flash, three
second pause

Gas valve fault
detected.

1. Control needs to be reset.

2. Control is wet or physically damaged.

1. Interrupt power supply

2. Replace gas control,
page 26

Page 16

TTW SERVICE PROCEDURE I

17

Burner Operation Inspection,

Adjustment, Cleaning and Replacement

Burner Inspection and Air Shutter Adjustment.

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).

Cast Iron Burner Air Shutter Adjustment

WARNING

Inner door and burner components may be HOT when performing this operation. Take

necessary precaution to prevent personal injury.

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.

Air Shutter

Air Shutter Nut

Page 17

TTW SERVICE PROCEDURE I

18

Burner Operation Inspection,

Adjustment, Cleaning and Replacement

Burner Cleaning

Remove Outer

door.

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.

Step 4. Disconnect pilot tube (7/16 wrench) and

Igniter/flame

sense wire

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

Slide inner door open

from left to right.

Feedline nut

Pilot tubing nut

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 check for 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.

Main burner

orifice

L.P. Main burner
orifice. Left hand

thread

Page 18

TTW SERVICE PROCEDURE II

19

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.

Igniter/flame

sense wire

Slide inner door open

from left to right.

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, check continuity

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 12. Visually inspect pilot tubing for kinks or cracks. If damage is

found replace pilot.

Ferrule

nut

Pilot

tubing

Igniter/flame sense

wire

Pilot

orifice

Feedline nut

Pilot tubing nut

Pilot

hood

Igniter/flame sense

electrode

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 check for 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.

Page 19

TTW SERVICE PROCEDURE III

20

Pressure Switch Testing and

Replacement

Pressure Switch Testing

WARNING

120 volt potential exposure. Use caution

Step 1. Position power switch on gas control

making voltage checks to avoid personal injury.

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)

With steps 1,2 & 3 complete,

disconnect wire leads from

pressure switch.

1

Pressure switch

wire leads

Slide pressure switch in direction of
arrow while tilting slightly away
from blower housing.

2

Pressure Switch

Use a multi-meter set to the

ohms setting. With blower off,

check across pressure

switch terminals.

Are switch contacts open?

(no electrical continuity)

Y

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?

Y

Switch contacts are OK.

See safety circuit trace

(page 29)

N

N

switch for blockage.

Y

Check tubing and

pressure tap on

Is there blockage?

Check tubing and pressure tap

on switch for blockage.

Is there blockage?

Y

Clear blockage

Y

N

Is vent

system

blocked

N

N

Is vent system length

listed on pages 7 & 8

Replace switch

(see page 19)

within vent table

specifications

Reconfigure vent

system to be

compliant with

vent tables.

Y

Y

N

See blower testing

(page 20)

Is blower OK?

N

Correct blower

problem.

Page 20

TTW SERVICE PROCEDURE III

21

Pressure Switch Testing and

Replacement

Pressure Switch Replacement

WARNING

120 volt potential exposure. Use caution

to avoid personal injury.

Step 1. Position gas control power switch

to “OFF” position.

Step 2. Remove the three screws (Phillips screw driver) from control access cover on blower assembly and

remove cover (see photo 3).

Pressure Switch

3 4

Step 3. Carefully remove pressure

switch from blower
housing (see photo 4)

Slide pressure switch in direction of
arrow while tilting slightly away
from blower housing.

5

Step 4. Disconnect tubing from

pressure switch.
(see photo 5)

6

Step 5. Disconnect yellow wires

from pressure switch
(see photo 6)

Step 6. Reconnect wires from step 5 to new pressure switch.

Step 7. Reconnect tubing to new pressure switch.

Step 8. Carefully position pressure switch into blower housing.

Step 9. Position gas control power switch to “ON” position and verify proper heater operation.

Step 10. Replace control access cover from step 2.

Page 21

TTW SERVICE PROCEDURE IV

22

Blower Testing and Replacement

Blower Testing

115 volt potential exposure. Use caution when

making voltage checks to avoid personal injury.

Step 1. Position gas control power switch

to “ON” position and adjust control to call for heat.

Step 2. Remove the three screws (Phillips Screw driver)

from control access cover on blower assembly and
remove cover (see photo 7).

Does blower energize Within 2

minutes?

N

8 9

Does blower energize after 2

minutes, run for 30 seconds

and shut down?

pressure switch

Y

tubing from blower.

Pressure tap

Pressure switch

See pressure switch

Y

Disconnect

(see photo 8)

tubing

testing

Page 18

manometer to

pressure tap of

(see photo 8)

Determine voltage

problem and correct.

7

Connect

blower.

11 12

Disconnect vent

system from top of

blower and remove

With blower running, and exhaust

adapter removed from top of blower,

is there a negative pressure of -2.15"

N

WARNING

vent adapter.

(see photo 10)

to -2.30" W.C.?

N

Is there 115vac across blue

and green wires

(see photo 13)

Y

Y

Remove exhaust

adapter

10

Blower OK

Replace blower

N

Disconnect cord set
shown in photo 9. Is

there 115VAC across

terminals shown in photo

11

N

Is there 115 VAC at

wall outlet?

Y

Check power cord

for damage.

N

Replace blower

Y

N

Y

Is there 115VAC across

terminals shown in

photo 12 ?

Incorrect supply
voltage polarity

Determine

power source

problem and

correct.

Repair or replace

power cord

Y

N

Replace
cord set

Reconnect cord set shown

in photo 9, is there

115VAC between blue wire

and green ground wire

(see photo 13)

N

Does cord set

N

have electrical

continuity?

Y

Replace gas

control

Y

Replace blower

Green ground

wire

Shown with pressure

switch removed.

13

Blue wire

Page 22

Blower removal

23

Step 1. Position gas control power switch to the “OFF” position.

Step 2. Unplug blower power cord from wall outlet.

Remove exhaust adapter

and retain for use on

new blower.

Step 3. Disconnect vent system from exhaust adapter on top of

blower.

Step 4. Remove exhaust adapter from blower (blade screw driver)

and retain for use on new blower

Step 5. Unplug cord sets from blower.

Step 6. Remove the three blower mounting screws

(¼" nut driver).

TTW SERVICE PROCEDURE IV

Blower Testing and Replacement

Blower Mounting

Screws

Step 7. Remove blower with gasket from water heater.

Blower Installation

Step 8. Clean any debris from jacket head of water heater.

Step 9. Set new blower with gasket in place using locating pins on

blower flange to line up with location holes in jacket head.
Be sure not to damage gasket.

Step 10 Secure blower in place using mounting screws from step 6.

Step 11. Re-install exhaust adapter from step 4.

Step 12. Reconnect vent system to

exhaust adapter.

Step 13. Reconnect cord sets from step 5.

Step 14. Plug blower power cord into wall outlet.

Locating Pins

on blower flange

Pin location holes in

jacket head

Blower

Cord Sets

Step 15. Position gas control power switch to the “ON” position.

Step 16. Verify proper blower operation.

Page 23

TTW SERVICE PROCEDURE V

24

Blower Temperature Switch Testing

and Replacement

Blower Temperature Switch
Testing.

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 and remove cover (see
photo 14).

Step 3. Locate blower temperature switch (see photo 15)

Switch Setting

Opens on rise @ approximately 165°F

Auto resets on fall @ approximately 130°F

Cool switch to

below 130°F

120 volt potential exposure. Use caution

WARNING

to avoid personal injury.

14

15

Air mixing inlet

Blower temperature

switch location

Disconnect wire leads to

switch. Using a multi-meter

set to the ohms setting, is

there continuity between the

switch terminals?

Y

Reconnect wire leads and

observe heater operation. Do

exhaust gas temperatures rise

to or above 165°F?

N

Do switch contacts

open?

N

Switch OK

Y

N

Y

Replace switch

(see page 23)

Replace switch

(see page 23)

N

Do switch contacts

open?

Y

temperature is too

Exhaust

hot.

Common causes for

high exhaust temperature

1. Vent length is below minimum allowable.

2. Vent diameter not to specification.

3. Restricted dilution air inlet.

4. Missing or deteriorated flue baffle.

5. Gas pressure is out of specification.

Page 24

TTW SERVICE PROCEDURE V

25

Blower Temperature Switch Testing

and Replacement

Blower Temperature Switch
Replacement.

Step 1. Position gas control power switch to the “OFF” position

and unplug heater from wall outlet.

Step 2. Remove the three screws (Phillips screw driver) from the

control access cover on blower and remove cover.
(see photo 16)

Step 3. Locate blower temperature switch (see photo 17)

Step 4. Disconnect red and yellow wire leads from switch.

120 volt potential exposure. Use caution

WARNING

to avoid personal injury.

17

Blower temperature

switch location

16

Step 5. With an appropriate tool such as side cutters, snip the

retaining lug from the blower housing to allow removal of
temperature switch (see photo 18).

Step 6. Remove switch from blower housing.

Step 7. Install new switch. Be sure switch is properly seated in

mounting area.

Step 8. Reconnect red and yellows wires to new switch. Wires are

interchangeable with either terminal.

Step 9. Position gas control power switch to the “ON” position

and verify proper heater operation.

Step 10. Replace control access cover from step 2.

18

Snip retaining lug

from blower housing

Page 25

TTW SERVICE PROCEDURE VI

26

Gas Control/Thermal Well Testing and

Replacement

Gas Control Testing

See pages 29 & 30 for gas control
input & output testing.

Thermal Well Testing (For water heaters with serial numbers that begin

with “J” or sooner.)

Position gas valve power
switch to the “OFF” position
and disconnect thermal well

harness from gas control.

Using a multi-meter set to

the Ohms setting,

determine the resistance of

thermal well sensors 1 & 2

(see photos 19 & 20)

Disconnect thermal

well wire harness

19

20

Using a multi-meter set to the ohms setting, insert one meter probe into center wire
position of thermal well connector, insert the second probe into either of the outside
wire positions (see photo 19).

Alternate the probe on the outside position to the opposite outside wire position
(see photo 20).

Once the thermal well resistance values are known, the water

temperature must also be known to determine if the resistance

values are correct. See page 25 to obtain water temperature.

Are thermal well resistance values correct?

Y

Thermal well OK

N

Replace thermal well

(see page 26)

Page 26

TTW SERVICE PROCEDURE VI

27

Gas Control/Thermal Well Testing and

Replacement

WARNING

Stored water may be HOT when performing the following steps in this procedure.

Take necessary precaution to prevent personal injury.

Determine Water Temperature Inside Tank (For water heaters with

serial numbers that begin with “J” or sooner.)

Note: It is important to understand once the resistance for the thermal well is determined from page 24, water flow
through the heater should not occur. Prior to performing the steps below, turn off the cold water supply to the
water heater. This will prevent cold water flow into the tank affecting the resistance value of thermal well.

Step 1. Position gas control power switch to “OFF” position.

Step 2. Draw approximately 4 gallons of water from drain valve into a container and discard. Draw an

additional gallon and immediately measure water temperature using an accurate thermometer. It may
be necessary to open a hot water faucet to allow heater to drain.

Step 3. Using the chart below, determine correct resistance value for the water temperature from step 2.

Example: If temperature of water is 84°F, then the resistance through the sensor would be

8449 (see shaded area). NOTE: Sensor resistance increases as the temperature

falls.

Sensor Resistance at Various Temperatures

In Degrees F

°F 012345678 9

40 26109 25400 24712 24045 23399 22771 22163 21573 21000 20445
50 19906 19383 18876 18383 17905 17440 16990 16553 16128 15715
60 15314 14925 14548 14180 13823 13477 13140 12812 12494 12185
70 11884 11592 11308 11032 10763 10502 10248 1000 9760 9526
80 9299 9078 8862 8653 8449 8250 8057 7869 7685 7507

90 7333 7165 7000 6839 6683 6531 6383 6238 6098 5961
100 582756975570544653265208509449824873 4767
110 466345624464436842744183409440063922 3839
120 375836793602352734533382331232443177 3112
130 304829862925286628082752269726432590 2538
140 248824392391234422982253220921662124 2083
150 204320041966192818911856182017861753 1720
160 168816561625159515661537150914811454 1427
170 140213761351132713031280125712351213 1191
180 117011501129111010901071195310351017 999
190 982 965 949 933 917 901 886 871 857 842
200 828 814 801 788 775 762 749 737 725 713

Page 27

TTW SERVICE PROCEDURE VI

28

Gas Control & Thermal Well Testing

and Replacement

Gas Control & Thermal Well Removal From Water Heater (For

water heaters with serial numbers that begin with “J” or sooner.)

Gas Control

Step 1. Position gas valve power switch to the “OFF”

position and Unplug Heater from power supply.

Thermal
Well

Step 2. Drain heater to a point below the gas

control level.

Step 3. Turn off gas supply to water heater and

disconnect gas piping from gas control.

Step 4. Disconnect wire harnesses and burner assembly

from gas control.

Step 5. Remove gas control & thermal well by rotating flats of Thermal Well counter clockwise (1-5/16"wrench).

Gas Control Removal From Thermal Well (For water heaters with

serial numbers that begin with “J” or sooner.)

Follow the steps below allows removal gas control from thermal well without removing thermal well from tank.

Step 1. Position gas control power switch to the “OFF” position and unplug water heater from power supply.

Step 2. Turn off gas supply to water heater and disconnect gas piping from gas control.

Step 3. Disconnect wire harnesses & burner assembly from gas control.

Step 4. Using gas control service tool (239-45991-00) available from your BWC parts supplier, Insert tool into

back of gas control (see photos below)

View from back of

control for clarity

Insert tool from

back of control

Service tool shown
inserted in to back

of control

Step 5. Pivot tool towards heater as far as possible (see photo below). Lift straight up on gas control. The

control should move about 1/8". Hold control in position and remove tool. Lift straight up on control to
remove completely from Thermal Well.

With service tool inserted, pivot tool back towards heater as

far as possible. Lift straight up on control, control will move

1/8". Remove tool and continue to lift straight up on control

to remove from Thermal Well.

Page 28

TTW SERVICE PROCEDURE VI

29

Gas Control & Thermal Well Testing

and Replacement

Gas Control Assembly to Thermal Well (For water heaters with serial

numbers that begin with “J” or sooner.)

Step 1. Install threaded end of thermal well into tank. Be sure

thermal well flange is positioned as shown in photo 24
for proper control alignment.

Step 2. Route wire leads back into relief opening.

(see photo 24)

Step 3. Align slots located on thermal well flange with tabs

located on back of gas control (see photos 24 & 25)

Thermal well flange
slots

24

Route wires
through relief
opening

Step 4. Carefully push control back onto thermal well flange

as far as possibletowards water heater. Slide control
down to lock into position.

Step 5. Install burner and connect pilot and feedline to gas

control.

Igniter/sensor

connection

Step 6. Reconnect wire harnesses to gas control

Step 7. Reconnect gas piping to gas control.

Ground Wire

connection

Step 8. To resume operation, follow the

5 pin

blower harness connection

3 pin
thermal well connection

25

Gas control Tabs

per the illustration.

Restore gas supply and check for gas
leaks.

instruction located on the lighting
instruction label or the lighting instruction
located in the installation and operation
manual.

Simulated Resistive
device

Page 29

Simulated Resistive Device Testing

30

TTW SERVICE PROCEDURE VII

Simulated Resistive Device Testing

Step 1. Position power switch on gas control to the

“OFF” position.

Step 2. Disconnect simulated resistive device from

gas control.

Step 3. Using a multi-meter set to the ohms setting

check resistance of simulated resistive
device. Resistance must be within 25,000
ohms and 45,000 ohms. If outside of this
range replace simulated resistive device.

Multi-meter set to
ohms setting

Electronic
“pin type”
Meter Probes

For water heaters with serial numbers
that begin with “J” or sooner.

Simulated Resistive
device

Simulated Resistive
device

Multi-meter set to
ohms setting

Electronic
“pin type”
Meter Probes

For water heaters with serial numbers
that begin with “K” or later.

Simulated Resistive
device

Page 30

TTW SERVICE PROCEDURE VIII

31

Safety Circuit Voltage Trace

Safety Circuit Voltage
Trace

NOTE: This procedure assumes a cool tank.

Step 2. Remove three screws (Phillips Screw driver) from control

access cover on blower and remove cover (see photo 26).

Position gas control switch to the “ON”

position and adjust thermostat dial to call

for heat, Is there 10 to 13 VAC between red

wire leading to blower temperature switch

and green ground wire?

Blower must be running during this

voltage check.
(see photo 27)

Y

N

Is LED on gas valve flashing the

“heartbeat” code (alternating

bright/dim)

Verify 120VAC to gas

control (see page 30)

120 volt potential exposure. Use caution

making voltage checks to avoid personal injury.

Y

N

WARNING

26

No voltage from gas control,

call for technical support.

Is there 10 to 13 VAC between yellow wire

leading from pressure switch and green

ground wire?

(see photo 27)

Y

Do you hear or can you see

the igniter sparking?

Y

Safety circuit
voltage is OK.

If burner does not light,

observe LED flash code on

gas valve and refer to

troubleshooting section on

page 13

N

N

Correct igniter/

sensor problem.

Check igniter/sensor

(see page 17)

is igniter/sensor OK?

27

Is there continuity

through blower

temperature switch?

(see page 22)

Determine cause of blower

temperature switch activation

and correct.

Faulty cord set or

Y

gas control.

Y

N

Yellow wire

leading from

pressure switch

Check for loose or

broken wire connection

at switch terminals

Green ground wire

Red wire leading to

blower temp. switch

Page 31

TTW SERVICE PROCEDURE IX

32

120 VAC Trace

120 VAC Circuit Trace

120 volt potential exposure. Use caution

WARNING

making voltage checks to avoid personal injury.

Step 1. Verify 120VAC and proper polarity at wall outlet.

Step 2. With unit plugged in and control power switch in the “ON” position verify LED status.

LED status

None, Control LED not

on or flashing.

Disconnect cord set as

shown in photo 28

Using a volt meter set to

volts AC, is there 120VAC

across terminals shown

in photo 29 ?

Y

Is there 120VAC across

terminals shown in

photo 30 ?

N

Incorrect supply
voltage polarity

N

Y

LED status

Short flash, once every

four seconds.

Waiting for

call for heat.

Reconnect cord set
shown in photo 28.

Disconnect wire harness

from gas control

(see photo 31).

LED status

“Heartbeat”, alternates

bright/dim.

Thermostat calling

for heat

28

Check for damage to AC

supply power cord.

N

Replace Blower

29

Y

Wire harness

LED status

Various flashing error

codes.

Verify error code as

listed on page 13

30

Repair damage

31

Locate black & white wires at connector, It
may be necessary to pull back wire sheath

to identify wire colors.

(see photo 32)

Is there 120VAC across

black & white wires as

shown in photo 32?

N

Call for technical

support.

Y

Replace gas

control.

32

Wire sheath pulled back to

identify wire colors

Check for 120VAC between black & white wires.

-NOTE-

Electronic meter probes required. Use care not to

damage connector during this check.

Page 32

TTW SERVICE PROCEDURE X

33

Dip Tube

Inspection and replacement

Dip Tube Inspection and Replacement

WARNING

Water Heater components and stored water may be HOT when performing the following

steps in this procedure. Take necessary precaution to prevent personal injury.

Step 1. Position on/off switch of gas control valve to “OFF” position and unplug water heater from wall outlet.

Step 2. Turn off cold water supply to water heater. Connect hose to drain valve of water heater and route to an

open drain. Open a nearby hot water faucet to vent heater for draining. Open drain valve of water
heater and allow heater to drain to a point below the inlet connection nipple.

Step 3. Disconnect inlet nipple from plumbing system.

Step 4 With an appropriate tool such as a pipe wrench, remove inlet nipple/dip tube from the water heater.

Use caution not to damage pipe threads.

Step 5. Visually inspect inlet nipple/dip tube. Inlet nipple/dip tube should be free of cracks and any blockage.

Hydro-jet slots should be open and free of any blockage.

Any damage such as cracks, restriction due to deformation or unintentional holes are not field
repairable and the inlet nipple/dip tube must be replaced.

Step 6. Upon completion of inspection or subsequent replacement, reinstall inlet nipple/dip tube into water

heater. Connect nipple to plumbing system, resume water supply and refill with water.

Step 7. To resume operation follow the instructions located on the lighting instruction label or the lighting

instructions located in the installation and operation manual.

Page 33

TTW SERVICE PROCEDURE XI

34

Anode

Inspection and replacement

Anode Inspection and Replacement

WARNING

Water Heater components and stored water may be HOT when performing the following

steps in this procedure. Take necessary precaution to prevent personal injury.

Step 1. Position on/off switch of gas control valve to the “OFF” position and unplug water heater from wall

outlet.

Step 2. Turn off cold water supply to water heater. Connect hose to drain valve of water heater and route to an

open drain. Open a nearby hot water faucet to vent water heater for draining. Open drain valve of
water heater and allow water heater to drain to a point below the outlet connection nipple.

Step 3. Disconnect outlet nipple from plumbing system.

Step 4 With an appropriate tool such as a pipe wrench, remove outlet nipple/anode from the water heater. Use

caution not to damage pipe threads.

Step 5. Visually inspect outlet nipple/anode. Outlet nipple/anode should show signs of depletion, this is

normal. If depletion is ½ of the original anode diameter (approximately ¾” diameter), replacement is
recommended. If any of the steel core of the anode is exposed, replacement is recommended.

Step 6. Upon completion of inspection or subsequent replacement, reinstall outlet nipple/anode into water

heater. Connect nipple to plumbing system, resume water supply and refill with water.

Step 7. To resume operation, follow the instructions located on the lighting instruction label or the lighting

instructions located in the installation and operation manual.

Page 34

TTW SERVICE PROCEDURE XII

35

Flue Baffle

Inspection and replacement

Remove blower to gain access to

Disconnect vent system

from exhaust adapter.

flue baffle

Step 1. Position gas control power switch to the “OFF” position

and unplug blower from wall outlet.

Step 2. Disconnect vent system from exhaust adapter on top of

blower.

Step 3. Unplug cord sets from blower. (see photo 33).

Step 4. Remove the three blower mounting screws

(¼" nut driver) (see photo 33).

Step 5. Remove blower with gasket from water heater.

Step 6. Remove flue baffle from Heater (see photo 34).

Step 7. Inspect baffle for deterioration, missing restrictors.

Clean any scale or debris build up. Replace with new
baffle as necessary.

Step 8. Reinstall baffle into flue tube. Be sure baffle

hanger tab are inserted into notch location at the
top of the flue tube (see photos 35 & 36).

33

Blower

Cord Sets

34

Blower Mounting

Screws

Flue Baffle

Step 9 Check Burner to insure no scale has accumulated during

this operation. See burner cleaning procedure on page 15.

Step 10. Reinstall blower on water heater. Connect vent

system and cords set to blower. Plug water heater
into wall outlet.

Step 11. To resume operation follow the lighting instruction

located on the lighting instruction label or the lighting
instruction located in the installation and operation
manual.

Flue tube

35

notch

36

Baffle shown

installed in flue

tube notch.

Page 35

BTU British Thermal Units

36

GPM Gallons per Minute
Hz Hertz
KW/h Killo-watts per hour
LED Light Emitting Diode
NPT National Pipe Thread

Ohms Ohms of resistance
PSI Pounds per Square Inch
RPM Revolutions per Minute

TCO Temperature Cut Off
VAC Volts Alternating Current
W.C. Inches of Water Column

°C Degrees Centigrade
°F Degrees Fahrenheit

Glossary of Terms

NOTES

Page 36

NOTES

37

NOTES

38

NOTES

39