Bradford White M1TW50S*FCX, M1TW40S*FBN, M1TW40S*FCX, M1TW50S*FBN, M4TW40T*FBN Service Manual
...
Save this manual for future reference
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
Loading...