Bradford White MI30T*F(BN User manual

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Manual 238-44943-00D
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
FEATURING
(To be performed ONLY by
qualified service providers)
For the Bradford White
Defender Safety System
®
Models:
MI30T*F(BN,CX,SX)
MI30S*F(BN, CX,SX)
MI303T*F(BN,CX,SX)
MI40T*F(BN,CX,SX)
MI403S*F(BN,CX,SX)
MI404T*F(BN,CX,SX)
MI503*F(BN,CX,SX)
MI50L*F(BN,CX,SX)
MI504S*F(BN,CX,SX)
MI60T*F(BN,CX,SX)
C(S,D)W2504T*F(BN,CX,SX)
M430T*F(BN,CX,SX)
M440T*F(BN, CX,SX)
M4403S*F(BN,CX,SX)
M4503*F(BN,CX,SX)
M460T*F(BN,CX,SX)
M1XR403S*F(BN,CX,SX)
M1XR504T*F(BN,CX,SX)
M2XR504T*F(BN,CX,SX)
M2XR65T*F(BN,CX,SX)
M2C504T*F(BN,CX,SX)
50T65F(B*N,C*X,S*X)
65T65F(B*N,C*X,S*X)
(*) Denotes Warranty Years
Gas Water Heaters
Flammable Vapor Ignition
Resistant Water Heaters
®
National Excelsior Company
www.excelsiorhvac.com
Subject to change without notice.

The Bradford White
DEFENDER
Safety System®
Flammable Vapor Ignition Resistant Water Heaters
Table of Contents
Page Service Procedure
Introduction 3 - - -
Trouble shooting Chart 4 - - -
Inner Door Gasket Removal, Inspection, Replacement and Installation 7 RG-I
Thermocouple/Thermopile Testing and Replacement 10 RG-II
Pilot Assembly Inspection Cleaning and Replacement 13 RG-III
Piezo Igniter, Electrode Testing and Replacement 14 RG-IV
White Rodgers/Robertshaw Gas Valve Testing and Replacement 15 RG-V
Honeywell Gas Control Testing, Disassembly, and Replacement 20 RG-VI
Burner Operation Inspection, Adjustment, Cleaning and Replacement 31 RG-VII
Resettable Thermal Switch Testing and Replacement 34 RG-VIII
ScreenLok®Flame Arrestor Cleaning 36 RG-IV
Dip Tube and Anode Inspection and Replacement 37 RG-X
Generic Parts List 39 - - -
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The Bradford White DEFENDER Safety System®
The Bradford White DEFENDER Safety System®was designed to resist
the ignition of flammable vapors that can occur outside of the water
heater. Use and installation are nearly identical to previous versions of
atmospherically fired and vented water heaters. A number of exclusive
design features are incorporated in the system that will require additional
knowledge on the part of the qualified service provider. The following
information will instruct service professionals on the function, proper
diagnosis and repair of water heaters employing the Bradford White
DEFENDER Safety System.
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 the
air is increased and its direction altered. The air then mixes in a normal
manner with the supplied gas and is efficiently combusted, producing very
low NOx emissions.
In the case where trace amounts of flammable vapors are present in the air
flowing into the combustion chamber, the vapors are harmlessly ignited
by the burner / pilot flame. If flammable vapors are in sufficient quantity
to prevent normal combustion, the burner/pilot flame is shut down.
Should the flammable vapors continue to the burner, the flame arrestor
plate prevents the flames from traveling backwards and igniting vapors
outside of the combustion chamber. The calibrated, multipurpose thermal
switch recognizes this and shuts down the pilot and main burner. This
switch also deactivates the burner and pilot in the unlikely event of
restricted airflow caused by severe lint, dust or oil accumulation on the
arrestor plate.
INTRODUCTION
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White Rodgers/Robertshaw Gas Valve Troubleshooting Chart
SYMPTOM PROBABLE CAUSE CORRECTIVE ACTION
Pilot Will Not Light
1. No incoming gas or too low gas
pressure.
2. Gas control knob set to wrong position.
3. Pilot light button not being fully
depressed when attempting to light pilot.
4. Pilot orifice or pilot tube is obstructed or
kinked.
5. Pilot electrode not sparking to pilot.
6. Piezo igniter not functioning.
1. Poor thermocouple connection at
combination thermostat/gas valve.
2. Thermocouple not fully engaged in pilot
assembly bracket.
3. Pilot flame is not fully enveloping the
thermocouple “hot” junction.
4. Weak or defective thermocouple.
5. Open ECO on combination thermostat/
gas valve.
6. Defective magnet in combination
thermostat/gas valve.
7 Resettable thermal switch has opened.
Pilot Will Not
stay lit
when button is
released
Pilot will light but
the main burner
will not come on
1. Combination thermostat/gas valve set too
low for desired water temperature.
2. Combination thermostat/gas valve
temperature is satisfied.
3. Insufficient gas supply or low gas
pressure.
4. Combination thermostat/gas valve has
wide differential or is out of calibration.
Pilot goes out
periodically (after
heating cycles,
once a day, once
a week etc.)
1. Insufficient combustion air supply.
2. Incorrect, clogged vent system/ vent
terminal or location.
3. Inconsistent gas supply or gas pressure.
Not enough hot
water
1. Combination thermostat/gas valve set too
low for desired water temperature.
2. Cold inlet water temperature is very cold.
3. High demand periods.
4. Incorrectly sized water heater for
application.
5. Combination thermostat/gas valve is out
of calibration/not functioning.
6. Out of spec dip tube is diluting hot water
with cold water.
1. Turn on gas supply and/or check line
pressure.
2. Review lighting instruction. Set
combination/thermostat
gas valve to correct position.
3. Review lighting instruction. Fully depress
pilot lighting button.
4. Clean, repair or replace.
5. Verify correct electrode position. Replace
pilot assembly.
6. Replace Piezo igniter.
1. Check connection at combination
thermostat/gas valve. Proper tightness
should be finger tight plus ¼turn.
2. Inspect thermocouple to ensure that it is
fully engaged into pilot bracket.
3. Adjust tip of thermocouple to be fully
engulfed by pilot flame.
4. Check thermocouple and replace if
necessary.
5. Check ECO continuity and replace
combination thermostat/gas valve if
necessary.
6. Check magnet operation and replace
combination thermostat/gas valve if
necessary.
7. Determine cause of switch activation. To
reset, depress button on resettable thermal
switch located on inner door.
1. Adjust temperature dial on combination
thermostat/gas valve.
2. Check temperature dial setting on
combination thermostat/gas valve.
3. Check gas supply and line pressure.
4. Check combination thermostat/gas valve
for proper operation, replace if
necessary.
1. Verify adequate combustion air is available
to the unit. Check and clear Jacket slot
openings of any dirt, dust, restrictions or
other obstructions. Inspect flame arrestor
plate and clean with stiff bristled brush
and/or vacuum to remove any debris
accumulation.
2. Check venting for proper sizing and proper
operation
3. Check gas supply and line pressure.
1. Check dial on combination thermostat/gas
valve.
2.Extremely cold water going into the heater
will decrease the amount of hot water
produced. It may be necessary to temper
incoming water supply.
3. Adjust high demand usage.
4. Contact Plumbing professional.
5. Check combination thermostat/gas valve
for proper operation, replace if
necessary.
6. Inspect dip tube and replace if necessary.
SERVICE
PROCEDURE
1. See Service Procedure
RG-V, Page 12.
4. See Service Procedure
RG-III, Page 10.
5. See Service Procedure
RG-III, Page 10.
6. See Service Procedure
RG-IV, Page 11.
4. See Service Procedure
RG-II, Page 8
5. See Service Procedure
RG-V, Page 14
6. See Service Procedure
RG-V, Page 13
2. See Installation &
operation manual.
3. See Service Procedure
RG-V, Page 12
4. See Service Procedure
RG-V, Page 12
1. See Service Procedure
RG-VIII, Page 22
3. See Service Procedure
RG-V, Page 12
5. See Service Procedure
RG-V, Page 12
6. See Service Procedure
RG-IX, Page 23
Flammable Vapor Ignition Resistant Water Heaters
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Honeywell Gas Control Troubleshooting Chart
LED Status Control Status Probable Cause
None (LED not on
or flashing
Gas Control is operating normally.
Pilot flame may not be present.
Check for pilot flame through sight
glass and light if necessary.
If set point knob is in “PILOT”
position then pilot flame is
detected. Turn set point knob to
desired setting.
One flash and
three second
pause
LED on
continuously
(Solid)
Set point knob has been recently
turned to the “OFF” position. Wait
until LED goes out before
attempting to relight
Two flashes and
three second
pause
Weak pilot signal detected. System
will reset when pilot flame is
sufficient.
1. Gas Control is functioning
normally.
2. Gas Control is not powered. Light
pilot.
3. Thermopile failure.
Gas Control is powered and waiting
for the set point knob to be turned to
a water temperature setting.
Set point knob was turned to “OFF”
position.
1. Thermopile failure
2. Unstable pilot
3. Pilot tube block or restricted.
4. Resettable thermal switch has
opened
Service
Procedure
If the pilot will not stay
lit replace pilot
assembly. If problem
persists replace Gas
Control.
Normal operation.
Adjust thermostat to
desired temperature
setting.
LED will go out and the
control will function
normally when the pilot
is lit.
1. See service
procedure RG-II
2. See service
procedure RG-III
3. See service
procedure RG-III
4. See service
procedure RG-VIII
Flammable Vapor Ignition Resistant Water Heaters
Green LED Indicator
Observe green LED indicator on
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.
Three flashes and
three second
pause
Insufficient water heating. System
will reset.
1. Temperature sensor out of
calibration
1. See service
procedure RG-VI
Four flashes and
three second
pause
Excessive tank temperature.
System must be reset.
1. Temperature sensor out of
calibration
2. Faulty Gas Control
1. See service
procedure RG-VI
2. See service
procedure RG-VI
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Honeywell Gas Control Troubleshooting Chart
LED Status Control Status Probable Cause
Five flashes and
three second
pause
Thermostat/well sensor fault.
Gas Control electronic fault
detected.
Seven flashes and
three second
pause
Eight flashes and
three second
pause
Standing pilot remains on while set
point knob is in “OFF” position.
1. Damage to the temperature
sensor.
2. Temperature sensor resistance
out of range.
1. Control need to be reset.
2. Control is wet or physically
damaged.
Pilot valve stuck in open position.
Service
Procedure
1. See service
procedure RG-VI
1. Reset Gas Control
2. Replace Gas
Control.
Replace Gas Control.
Flammable Vapor Ignition Resistant Water Heaters
Green LED Indicator
Observe green LED indicator on
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.
6
Water leak detected by accessory
module.
Six flashes and
three second
pause
Excessive amount of water in drain
pan/water dam.
1. Check T&P valve
2. Check all water
fittings.
3. Pressurize and leak
test tank.
6
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Inner Door Removal Procedure
Step 1. Rotate knob of the combination
thermostat/gas valve to the “OFF” position.
Step 2. Remove outer jacket burner access door
Step 3. Inner Door Removal.
a) Disconnect resettable thermal switch wire leads (leading from Gas Control/gas valve).
b) Remove (2) hex drive screws from right side inner door.
c) Remove (2) hex drive screws from flange section of inner door.
d) Remove (2) hex drive screws from left side inner door.
e) Remove inner door and inspect per step 4.
Step 4. Fully inspect inner door gaskets for the following:
>Tears >Other imperfections that will inhibit proper seal
>Missing Material >Gasket adhesion to inner door
>Cracks >Material left on combustion chamber (around opening)
>Dirt or debris
If the gasket is not effected by any of the above, gasket replacement is not required. If replacement is required,
proceed to Inner Door Gasket Replacement Procedure.
Inner Door Gasket Replacement Procedure.
WARNING
If the information in these instructions is not
followed exactly, a fire or explosion may result causing
property damage, personal injury or death.
Step 5. After inspection of inner door as noted in step 4, completely remove gasket and adhesive residue from right
and left side inner doors as needed.
Step 6. Use RTV sealant (recommended bead size 1/8") to secure the inner door gasket to the inner door sections
(right & left). Refer to illustration on next page for proper application. Note the overlap configuration in the
flange area of the inner door. Set the flange section first, this will help to achieve the proper over lap position.
For Robertshaw Control,
rotate knob clockwise to
the “OFF” position.
The Bradford White
DEFENDER
Safety System®
For White Rodgers Control,
depress knob slightly and rotate
clockwise to the “OFF” position.
For Honeywell Control, rotate
knob counter-clockwise to the
“OFF” position.
SERVICE PROCEDURE RG-I
Inner Door/Gasket Removal, Inspection
Replacement and Reinstallation
Resettable Thermal Switch
Wire Connection
Hex Drive Screws
Right and Left Side Inner Door.
Hex Drive Screws at
Flange Area of Inner Door
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Installation of Inner Door With Gasket.
WARNING
Stripped fastener connections may allow
for seal breach of inner door. A seal
breach may result in a fire or explosion
causing property damage, personal injury
or death. Do not over tighten screws in
steps 8, 10 and 11.
If a fastener connection is stripped,
contact the manufacturer listed on the
water heater rating plate.
Step 7. Clean any residual gasket residue or other debris
from combustion chamber surface before
installing the inner door/gasket assembly.
Step 8. Place the left side inner door into position first.
Firmly position the radiused channel of the inner
door aroundthe feedline. Using the (2) hex drive
screws from step 3d, secure left side inner door in
place. DO NOT OVER TIGHTEN SCREWS.
Step 9 Position thermocouple, pilot tube and Piezo wire
against left side inner door flange gasket.
DO NOT ROUTE THROUGH RADIUSED
CHANNEL WITH FEEDLINE.
Radiused Channel for
Feedline
Position thermocouple/thermopile,
pilot tube and piezo wire.
PLACE FLANGE
SECTIONS FIRST
RECOMMENDED PATTERN
FOR RTV SEALANT
GASKET
OVERLAP MUST
BE AS SHOWN
±1/32" ENLARGED
VIEW OF
FLANGE AREA
EXPANDED VIEW
VIEW WITH GASKETS
IN PLACE
SERVICE PROCEDURE RG-I
Inner Door/Gasket Removal, Inspection
Replacement and Reinstallation
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Step 10. Firmly place right side inner door flange against the left side inner door flange and secure with (2) hex drive
screws from step 3c. DO NOT OVER TIGHTEN SCREWS.
Step 11. Align right side inner door to combustion chamber and verify the fastener holes of the combustion
chamber are aligned with the right side inner door slotted opening. Verify seal integrity around combustion
opening. Secure right side inner door using (2) hex drive screws from step 3b.DO NOT OVER TIGHTEN
SCREWS. Verify both left and right sides of the inner door are properly positioned and sealed against
the combustion chamber.
Step 12. Reconnect lead wires from combination thermostat/gas valve to resettable thermal switch (See photo in step
3). Note, wire terminations are interchangeable with either resettable thermal switch connections.
Step 13. Replace outer jacket burner access door.
Step 14. To resume operation follow the instructions located on the lighting instruction label or the lighting instructions
located in the installation and operation manual.
Verify threaded hole
alignment with slotted
openings in inner door.
Secure flange with
hex drive screws.
SERVICE PROCEDURE RG-I
Inner Door/Gasket Removal, Inspection
Replacement and Reinstallation
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Step 1. Closed circuit testing is the preferred method for testing thermocouple. Following the lighting instruction
label on the heater, proceed to light the pilot and allow to operate for three minuets. If the pilot will not stay
lit, hold the pilot button (located on the combination thermostat/gas valve) down during this test
Step 2. Using a multimeter capable of measuring millivolts, connect one lead
using an alligator clip to the copper sheath of the thermocouple, use the second lead of the multi meter to
probe the top terminal located at the back of the combination thermostat/gas valve.
Step 3. If meter reads 10 millivolts or higher, the thermocouple is OK. If reading is below 10 millivolts,
replace the thermocouple.
CLOSED CIRCUIT THERMOCOUPLE TESTING (White Rodgers Control)
The Bradford White
DEFENDER
Safety System®
Probe top terminal on
back of combination
thermostat/gas valve Alligator clip to copper
sheath of thermocouple
Step 1. Disconnect thermocouple from combination thermostat/gas valve.
Step 2. Connect a thermocouple adaptor
(BWC P/N 239-44642-00, Robertshaw P/N 75036) at the
thermocouple location in the combination thermostat/gas valve.
Step 3. Reconnect thermocouple to adaptor. Make certain all
connections are tight (finger tight plus ¼turn)
Step 4 Using a multimeter capable of measuring millivolts, connect
one alligator clip to the set screw of the adaptor, and the other
alligator clip to copper portion of the thermocouple.
Step 5. Following the lighting instruction label on the heater, proceed to light the pilot and allow to operate for
three minuets. If the pilot will not stay lit, hold the red reset button (located on the combination
thermostat/gas valve) down during this test
Step 6. If meter reads 13 millivolts or higher, the thermocouple is OK. If reading is below 13 millivolts
replace the thermocouple.
CLOSED CIRCUIT THERMOCOUPLE TESTING (Robertshaw Control)
SERVICE PROCEDURE RG-II
Thermocouple/Thermopile Testing and
Replacement
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