Bradford-White M1XR403S-FBN, MI403S-F-BN, MI404T-F-BN, M450S-F-BN, MI50L-F-BN User Manual
...
SERVICE
MANUAL
Flammable Vapor Ignition Resistant Water Heater
Troubleshooting Guide
and Instruction for Service
(To be performed ONLY by qualified service providers)
For the Bradford White
Defender Safety System
™
Models:
MI30T*F(BN,CX)2
MI30S*F(BN,CX)2
MI303T*F(BN,CX)2
MI40T*F(BN,CX)2
MI403S*F(BN,CX)2
MI404T*F(BN,CX)2
MI503*F(BN,CX)2
MI50L*F(BN,CX)2
MI504S*F(BN,CX)2
M430T*F(BN,CX)2
M4403S*F(BN,CX)2
M4403T*F(BN,CX)2
M450S*F(BN,CX)
M1XR403S*F(BN,CX)2
M1XR504T*F(BN,CX)2
M2XR504T*F(BN,CX)2
M2C504T*F(BN,CX)
50T65F(BN,CX)
Manual 44943A
(*) Denotes Warranty Years.
Save this manual for future reference
2
Flammable Vapor Ignition Resistant Water Heater
Table of Contents
Page Service Pr
ocedure
Introduction 3 - - -
Trouble shooting Chart 4 - - -
Inner Door Gasket Removal, Inspection, Replacement and Installation 5 RG-I
Thermocouple Testing and Replacement 8 RG-II
Pilot Assembly Inspection Cleaning and Replacement 10 RG-III
Piezo Igniter and Electrode Testing 11 RG-IV
Combination Thermostat/Gas Valve Testing and Replacement 12 RG-V
Burner Operation Inspection, Adjustment, Cleaning and Replacement 17 RG-VI
Resettable Thermal Switch Testing and Replacement 20 RG-VII
ScreenLok Flame Arrestor Cleaning 22 RG-VIII
Dip Tube and Anode Inspection and Replacement 23 RG-IX
Generic Parts List 25 - - -
3
Introduction
The Bradf
ord White DEFENDER Safety System
™
The Bradford White DEFENDER Safety SystemTMwas 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 .
Ho
w the Safety System Works
™
During normal operation, air for combustion is drawn into the water heater through the
openings 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 supplied gas
and is efficiently combusted, producing very low NOx emissions. In the unlikely event trace
amounts of flammable vapors are present in the air flowing into the combustion chamber, the
vapors are harmlessly ignited by the burner / 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 burn, 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. If accumulation occurs, the
ScreenLok flame arrestor can be easily cleaned and when the inner door is properly secured
the unit can then be placed in operation. A cleaning procedure is included in this service
manual.
4
SYMPTOM PROBABLE CA
USE
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. Combination thermostat/gas valve
set too low for desired water temp.
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.
1. Insufficient combustion air supply.
2. Incorrect, clogged vent system/ vent
terminal or location.
3. Inconsistent gas supply or gas
pressure.
1. Combination thermostat/gas valve
set too low for desired water temp.
2. Cold inlet water temp. 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. 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.
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. 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.
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
4. See Service Procedure
RG-II, Page 8.
5. See ServiceProcedure
RG-V, Page 13.
6. See Service Procedure
RG-V, Page 13.
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.
1. Check connection at combination thermostat/gas
valve. Proper tightness should be finger tight
plus 1/4 turn.
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.
Pilot will not
stay lit when
button is
released
Pilot will light
but the main
burner will
not come on
Pilot goes out
periodically
(after heating
cycles, once a
day, once a
week etc.)
Not enough
hot water
SERVICE
PROCEDURE
Tr
oubleshooting Char
t
Flammable Vapor Ignition Resistant Water Heaters
SERVICE PROCEDURE RG-I
Inner Door/Gasket Removal, Inspection
Replacement and Reinstallation
Inner Door Remo
v
al 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 combination thermostat/gas valve).
b) Remove (2) 1/4" hex drive screws from right side inner door.
c) Remove (2) 1/4" drive screws from flange section of inner door.
d) Remove (2) 1/4" 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 Gask
et Replacement Procedure.
Inner Door Gasket Replacement Procedure
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.
5
! WARNING
If the information in these instructions is not followed exactly, a fire or
explosion may result causing property damage, personal injury or death.
!
1/4" Hex Drive Screws at
Flange Area of Inner Door
1/4" Hex Drive Screws
Right and Left Side Inner Door
Resettable Thermal Switch
Wire Connection
6
SERVICE PROCEDURE RG-I
Inner Door/Gasket Removal, Inspection
Replacement and Reinstallation
Installation of Inner Door with Gasket
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 around the feedline. Using the 1/4” 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 N
OT ROUTE THROUGH RADIUSED
CHANNEL WITH FEEDLINE.
! 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.
!
Radiused Channel for Feedline
Position thermocouple,
pilot tube and Piezo wire
7
SERVICE PROCEDURE RG-I
Inner Door/Gasket Removal, Inspection
Replacement and Reinstallation
Step 10. Firmly place right side inner door flange against the left side inner door flange and secure with two
1/4” 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 chamber opening. Secure right side inner door using 1/4” 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
1/4" drive screws
8
SERVICE PROCEDURE RG-II
Thermocouple Testing and Replacement
Closed Circuit Thermocouple Testing
Step 1. Disconnect thermocouple from combination thermostat/gas valve.
Step 2. Connect a thermocouple adapter (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 adapter. make certain all connections
are tight (finger tight plus 1/4 turn)
Step 4. Using a multimeter capable of measuring millivolts, connect one
alligator clip to the set screw of the adapter, 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 minutes. 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 below13 millivolts replace
the thermocouple.
Open Cir
cuit Thermocouple Tes
ting
Step 1. Disconnect thermocouple from combination thermostat/gas valve.
Step 2. Using a multimeter capable of measuring millivolts, connect one
alligator clip to the end ball or contact portion of the
thermocouple, and the other alligator clip to copper portion of the
thermocouple.
Step 3. Following the lighting instruction label on the heater, proceed to
light the pilot and allow to operate for three minutes. It will be
necessary to hold the red reset button continuously
throughout this test. If meter reads 20 millivolts or higher, the thermocouple is OK. If reading is
below20 millivolts, replace the thermocouple.
9
SERVICE PROCEDURE RG-II
Thermocouple Testing and Replacement
Thermocouple Replacement
Step 1. Turn off gas supply to water heater. Rotate knob of combination
thermostat/gas valve to “OFF” position.
Step 2. Remove outer jacket door.
Step 3. Remove right side of inner door per SERVICE PROCEDURE RG-I,
steps 3a through 3c.
Step 4. Disconnect thermocouple from combination thermostat/gas valve (3/8" wrench). Locate other end of
thermocouple inside of combustion chamber and remove from pilot bracket. Pull firmly pulling away
from the pilot assembly.
Step 5. Install new thermocouple into pilot bracket making certain the
thermocouple is fully engaged into the pilot bracket. Position
thermocouple against left side inner door flange at its original
position. Connect other end of thermocouple to combination
thermostat/gas valve (finger tight + 1/4 turn).
Step 6. Inspect inner door gasket per SERVICE PROCEDURE RG-I, Step 4.
Step 7. Install right side inner door per SERVICE PROCEDURE RG-I, Step 10 through Step 13.
Step 8. To resume operation follow the instructions located on the lighting instruction label or the lighting
instructions located in the installation and operation manual.
Position thermocouple,
in its original position
Make certain thermocouple is
fully engaged into bracket
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