Bradford White GX225S BN Series User manual

Save this manual for future reference
Manual 238-46647-00B
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
GX225S*BN
GX155S*BN
25X78B*N
55X80B*N
M1XR65T*(BN,CX,SX)
MI75S*(BN,CX,SX)
M2XR75S*(BN,CX,SX)
MI100T*(BN,CX,SX)
65T65*(BN,CX,SX)
75T80*(BN,CX,SX)
C(S,D)W275T*(BN,CX,SX)
(*) Denotes Warranty Years
For Models Using White Rodgers,
Robertshaw and Honeywell Gas Control
Atmospheric Gas Water Heaters
(GX155S6BN Model Shown)

Table of Contents
Service
Page Procedure
Troubleshooting Chart White Rodgers and Robertshaw Gas Control 3 - - -
Troubleshooting Chart Honeywell Gas Control 4 - - -
Thermocouple Testing and Replacement White Rodgers and Robertshaw Gas Control 6 AG-I
Thermopile Testing and Replacement Honeywell Gas Control 7 AG-I
Pilot Assembly Inspection Cleaning and Replacement
White Rodgers and Robertshaw Gas Control 9 AG-II
Pilot Assembly Inspection Cleaning and Replacement Honeywell Gas Control 10 AG-II
Gas Control Testing and Replacement White Rodgers and Robertshaw 12 AG-III
Gas Control Replacement Honeywell 12 AG-III
Honeywell Thermowell Testing and Replacement 16 AG-III
Honeywell Gas Control and Thermowell Replacement 18 AG-III
Burner Operation Inspection, Adjustment, Cleaning and Replacement 20 AG-IV
Dip Tube and Anode Inspection and Replacement 23 AG-V
Page 2
2

Troubleshooting Chart
Symptom Probable Cause Corrective Action
Pilot will not light
1. Noincoming gas or too low gas
pressure.
2. Gas control knob set to wrong position.
3. Pilot lightbutton not being fully
depressed when attempting to lightpilot.
4. Pilot orificeor pilot tube isobstructed or
kinked.
1. Poor thermocoupleconnection at
gas control.
2. Thermocouplenot fully engaged inpilot
assembly bracket.
3. Pilot flameisnot fully enveloping the
thermocouple“hot” junction.
4. Weak or defectivethermocouple.
5. Open ECO on gas control.
6. Defectivemagnet ingas control.
Pilot will not
stay lit
when button isreleased
Pilot will light, butthe
mainburner will not
comeon
1. Gas Control set too low for desired water
temperature.
2. Gas Control temperatureissatisfied.
3. Insufficient gas supply or low gas
pressure.
4. Gas Control has widedifferential or isout
of calibration.
Pilot goes out
periodically (after
heating cycles, oncea
day, onceaweek 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. Gas Control set too low for desired water
temperature.
2. Cold inlet water temperatureisvery cold.
3. High demand periods.
4. Incorrectly sized water heater for
application.
5. Gas Control isoutof calibration/not
functioning.
6. Outof spec dip tube isdiluting hot water
with cold water.
7. Integrated mixing deviceisset too low for
desired water temperature.
1. Turnon gas supply and/or check line
pressure.
2. Review lighting instruction. Set
gas control to correctposition.
3. Review lighting instruction. Fully depress
pilot lighting button.
4. Clean, repair or replace.
1. Check connection at gas control.
Proper tightness should be finger tightplus
¼ turn.
2. Inspectthermocoupleto ensurethat itis
fully engaged into pilot bracket.
3. Adjust tip of thermocoupleto be fully
engulfed by pilot flame.
4. Check thermocoupleand replaceif
necessary.
5. Check ECO continuity and replace
gas control ifnecessary.
6. Check magnet operation and replace
gas control ifnecessary.
1. Adjust temperaturedial on gas control.
2. Check temperaturedial setting on
gas control.
3. Check gas supply and line pressure.
4. Check gas control
for proper operation, replaceif
necessary.
1. Verify adequate combustion air isavailable
to theunit. Check and clear Jacket slot
openings of any dirt, dust, restrictions or
other obstructions.
2. Check venting for proper sizing and proper
operation
3. Check gas supply and line pressure.
1. Check dial on gas control.
2.Extremely cold water going into thewater
heater will decrease theamount of hot
water produced. Itmay be necessary to
temper incoming water supply.
3. Adjust high demand usage.
4. ContactPlumbing professional.
5. Check gas control
for proper operation, replaceif
necessary.
6. Inspectdip tube and replaceifnecessary.
7. Reset deviceusing theprocedure
intheinstructions included with thedevice.
Service
Procedure
1. See ServiceProcedure
AG-III, Page 12.
4. See ServiceProcedure
AG-II, Page 9.
4. See ServiceProcedure
AG-I, Page 6
5. See ServiceProcedure
AG-III, Page 12
6. See ServiceProcedure
AG-III, Page 12
2. See Installation &
operation manual.
3. See ServiceProcedure
AG-III, Page 12
4. See ServiceProcedure
AG-III, Page 12
3. See ServiceProcedure
AG-III, Page 12
5. See ServiceProcedure
AG-III, Page 12
6. See ServiceProcedure
AG-V, Page 23
Page 3
For ModelsUsing White Rodgersor Robertshaw Thermostat
3

Troubleshooting Chart
For ModelsUsing Honeywell Gas Control
Observe 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:
LED Status Control Status Probable Cause
Not on and/or
not flashingPilot flamemay not be present.
Gas control is in the“PILOT” position and
thepilot flameis detected.
One flash and athree
second pause.
LEDis on continuouslyGas control has recentlybeen turned to the
“OFF” position. Wait until LEDgoes out
before attempting to relight.
Two flashes and athree
second pause.
Weak pilot flamedetected. System will reset
when pilot flameis sufficient.
Three flashes and a
three second pause.
Tank temperature fault.
System will reset.
Pilot flameis not present.
Gas control is powered and waiting for theset
point knob to be turned to awater
temperature setting.
Gas control was turned to the“OFF” position.
1. Thermopilefailure
2. Unstablepilot.
3. Pilot tube blocked or restricted.
Thermowell sensor out of calibration.
Service
Procedure
1. Lite pilot per theinstructions
located on thelighting
instructions label or the
lighting instructions located in
theinstallation and operation
manual.
2. See Service
Procedure AG-I,
Page7.
Normal operation. Adjust gas
control set point knob to
desired temperature level.
1. Wait for LEDto goout.
2. Lite pilot per theinstructions
located on thelighting
instructions label or the
lighting instructions located in
theinstallation and operation
manual.
1. See Service
Procedure AG-I,
Page7
2& 3. See Service
Procedure AG-II,
Page10.
1. See Service
Procedure AG-III,
Page16
Four flashes and athree
second pause.Excessivetank temperature.Thermowell sensor out of calibration.
1. See Service
Procedure AG-III,
Page16
Page4
LEDIndicator
4

Troubleshooting Chart (cont.)
For ModelsUsing Honeywell Gas Control
Five flashes and athree
second pause.Thermowell fault
Seven flashes and a
three second pause.Gas control faultdetected.
1. Damageto thermowell
wires.
2. Thermowell sensor resistance
out of range.
1. Gas control needs to be reset.
2. Gas control is wet or physically
damaged.
See Service Procedure
AG-III,Page16
Lite pilot per theinstructions
located on thelighting
instructions label or the
lighting instructions located in
theinstallation and operation
manual.
Eightflashes and athree
second pause.
Pilot flameremains on whilegas control is in
the“OFF” position.Pilot valve stuck in theopen position.
Replace gas control.
See Service Procedure
AG-III,Page18.
Page5
LED Status Control Status Probable Cause Service
Procedure
5

THERMOCOUPLE REPLACEMENT
Step 1. Turn off gas supply to water heater. Rotate knob of gas control to “OFF” position.
Step 2. Remove outer jacket door.
Step 3. Slide open inner combustion chamber door.
Step 4. Disconnect thermocouple from gas control. 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. Connect other end of thermocouple to gas control (finger tight + ¼ turn).
Step 6. Route carefully through the relief opening in the combustion chamber skirt.
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.
Step 8. Slide inner door closed when finished.
SERVICE PROCEDURE AG-I
ThermocoupleTesting and Replacement
For ModelsUsing White Rodgers or
Robertshaw Gas Control
Page6
Figure 3
For White Rodgers gas
control,depress knob
slightlyand rotate
clockwise to the “OFF”
position.
For Robertshaw gas
control,rotate knob
clockwise to the “OFF”
position.
Step 1. Disconnect thermocouple from gas control.
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. A reading of 20 to 30 millivolts indicates good thermocouple output.
OPEN CIRCUIT THERMOCOUPLE TESTING
Figure 4
Thermocoupleposition
Figure 1
Figure 2
NOTE:
Itwill be necessary to holdthe gas control
knob down in the “PILOT” position
continuouslythroughout this test.
6

Figure 6
OPEN CIRCUIT THERMOPILE TESTING
Step 1. Disconnect red and white thermopile wires from the wire harness leading to the gas control.
Step 2. Using a multimeter capable of reading millivolts, check across thermopile leads.
Step 3. Following the instructions located on the lighting instruction label or the lighting instructions located in the
installation and operation manual, proceed to light the pilot and allow the gas control to operate for three
minutes.
Step 1. Closed circuit testing is the preferred method for testing the thermopile. Following the instructions
located on the lighting instruction label or the lighting instructions located in the installation and operation
manual, proceed to light the pilot and allow the control to operate for three minutes.
Step 2. Using a multimeter capable of measuring millivolts, measure across thermopile connections at the
gas control (see Figure 6).
CLOSEDCIRCUIT THERMOPILE TESTING
Thermopile
Connections at gas
control
Page7
Figure 5
Gas Control
Knob
SERVICE PROCEDURE AG-I
ThermocoupleTesting and Replacement
For ModelsUsing Honeywell Gas Control
NOTE:
Itmay be necessary to holdthe gas
control knob down in the “PILOT” position
continuouslythroughout this test.
NOTE:
Itmay be necessary to holdthe gas
control knob down in the “PILOT” position
continuouslythroughout this test.
InaCLOSEDCIRCUIT test:
Any reading over 300 millivolts
indicates good thermopileoutput.
For readingsunder 300 millivolts
replacement of thermopileis
recommended.
Inan OPEN CIRCUIT test:
Any reading over 400 millivolts
indicates good thermopileoutput.
For readingsunder 400 millivolts
replacement of thermopileis
recommended.
7

Figure 7
SERVICE PROCEDURE AG-I
ThermopileTesting andReplacement
ForModelsUsing Honeywell Gas Control
Step 1. Turn off the gas supply to the water heater by rotating the gas control knob to the “OFF” position
(see Figure 7).
Step 2. Remove outer jacket door.
Step 3. Remove or slide open the inner combustion chamber door.
Step 4. Disconnect red and white thermopile wires from the wire harness leading
to the gas control.
Step 5. Disconnect the thermopile from the pilot bracket using a 7/16” open-end wrench.
Step 6. Install the new thermopile into the pilot bracket and tighten the threads using care not to damage the
thermopile lead wires. Route new wires through the appropriate opening in the combustion chamber.
Step 7. Reconnect the lead wires being careful to match the colors (red to red and white to white).
Step 8. Reinstall, or slide closed, inner combustion chamber door.
Step 9. Replace the outer door.
Step 10. To resume operation follow the instructions located on the lighting instruction label or the lighting
instructions located in the installation and operation manual.
Page8
THERMOPILE REPLACEMENT
Gas Control Knob
(ShowninOFF
position)
8

PILOT ASSEMBLY INSPECTION,
CLEANING ANDREPLACEMENT
Step 1. Turn off gas supply to water heater. Rotate knob
of gas control to “OFF” position.
Step 2. Remove outer jacket door.
Step 3. Slide open inner combustion chamber door.
Step 4. Disconnect thermocouple, pilot tube,
and feedline from gas control.
NOTE: Feedline nut for natural gas control
uses right hand threads, LP control uses left hand thread.
Step 5. Remove burner assembly from combustion chamber.
Step 6. Remove pilot assembly from feedline.
Step 7. Inspect pilot for the following:
a) Primary air openings for blockage. Must be free from any
debris (dirt, lint, etc).
b) Kinks or cracks in the pilot tube. If found,
the pilot must be replaced.
Step 8. Inspect pilot orifice:
a) Remove ½" nut from bottom of pilot assembly.
b) Remove pilot tube and pilot orifice.
c) inspect pilot orifice for blockage, must be cleaned or replaced.
SERVICE PROCEDURE AG-II
Pilot AssemblyInspection,Cleaning
andReplacement ForModelsUsing White
RodgersorRobertshawGas Control
Step 9. Install pilot assembly to feedline, secure with screw from step 6.
Step 10. Re-Install burner assembly into combustion chamber, connect feedline, pilot tube and thermocouple
to gas control.
Step 11. Slide inner combustion chamber door closed and re-attach outer jacket door.
Step 12. To resume operation follow the instructions located on the lighting instruction label or the lighting
instructions located in the installation and operation manual.
Page9
Primary Air
Opening
R
ForWhiteRodgersgas
control,depress knob
slightlyandrotate
clockwiseto the“OFF”
position.
ForRobertshawgas
control,rotateknob
clockwiseto the“OFF”
position.
Pilot Orifice
FeedlineNut
Figure 8
Figure 9
Figure 10
Figure 11
9

SERVICE PROCEDURE AG-II
Pilot AssemblyInspection, Cleaning
and Replacement For ModelsUsing
Honeywell Gas Control
R
Step 1. Turn off the gas supply to the water
Heater. Rotate gas control knob to the
“OFF” position.
Step 2. Remove outer jacket door.
Step 3. Remove burner assembly per
Service Procedure AG-IV page 20.
Step 4. Remove the pilot assembly from the burner assembly.
Step 5. Inspect the pilot assembly for the following:
a)Primary air opening for any blockage .
Must be free from any debris (dirt, lint, dust, etc.).
b) Kinks or cracks in the pilot tube. If found, the pilot
must be replaced.
Step 6. Inspect pilot orifice:
a) Remove 7/16” nut from the bottom of the pilot assembly.
b) Remove pilot tube and pilot orifice.
c) Inspect pilot orifice for blockage, must be free from any debris (dirt, lint, dust, etc.).
d) Reassemble pilot orifice and pilot tube to pilot assembly.
Step 7. Install pilot assembly to burner assembly using the screw from Step 4.
Step 8. Reinstall burner assembly per Service Procedure AG-IV page 22: Steps 10 through 12.
Step 9. To resume operation follow the instructions located on the lighting instruction label or the lighting
instructions located in the installation and operation manual.
Step 10. Check all gas connections for gas leaks using a soapy water solution.
PILOT ASSEMBLY INSPECTION,
CLEANING ANDREPLACEMENT
Figure 12
Figure 13
Primary Air
Opening
Pilot Orifice
Page10
10