Bradford White ECO-DEFENDER Series User manual

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Manual 238-51546-00B REV 10/18
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
URG230T*N
URG240S*N
URG240T*N
URG250L*N
URG250H*N
URG250T*N
URG250S*N
URG130T*N
URG140T*N
URG150T*N
(*) Denotes Warranty Years
Flammable Vapor Ignition Resistant
Water Heaters
Ultra Low NOx Gas Water Heaters

2
ED-X
Flue Baffle Inspection & Replacement ....................................................................................26 ED-XI
ScreenLok® ...............................................................................................................................27 ---
Glossary of Terms......................................................................................................................28 ---
Parts List .....................................................................................................................................29 ---
The Bradford White
ECO
DEFENDER
Safety System®
Ultra Low NOx Gas Water Heaters
Page ED Service Procedure
Introduction.................................................................................................................................4 ---
How to Use This Manual ..........................................................................................................5 ---
Tools Required for Service........................................................................................................5 ---
Troubleshooting .........................................................................................................................6 ---
Burner Operation Inspection, Cleaning & Replacement....................................................... 10 ED-I
Pilot Inspection, Testing & Replacement .................................................................................12 ED-II
Gas Control Testing & Replacement........................................................................................13 ED-III
Chamber Sensor Testing ...........................................................................................................16 ED-IV
Thermopile Testing and Replacement......................................................................................17 ED-V
Igniter, Electrode Testing and Replacement ............................................................................18 ED-VI
Resettable Thermal Switch Testing and Replacement............................................................19 ED-VII
Diptube Inspection and Replacement .......................................................................................21 ED-VIII
Anode Inspection & Replacement............................................................................................22 ED-IX
Inner Door Removal, Inspection & Replacement...................................................................23
2

3
ECO Defender Series
WARNING: If the information in these
instructions is not followed exactly, a fire or
explosion may result causing property damage,
personal injury, or death.
WHAT TO DO IF YOU SMELL GAS!
x
x
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.
x
x
Installation and service must be performed by a qualified
installer, service agency or the gas supplier.
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 dangerous operation.
Verify proper operation after servicing.
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 extremely
flammable. To prevent the 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
appliance 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
smoke or have open flame near the faucet at the time it is open.
WARNING
FAILURE TO INSTALL AND MAINTAIN A NEW, LISTED ¾” X ¾”
TEMPERATURE AND PRESSURE RELIEF VALVE WILL RELEASE
THE MANUFACTURER FROM ANY CLAIM THAT MIGHT RESULT
FROM EXCESSIVE TEMPERATURE AND PRESSURES.
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 applied to the nipples containing a
plastic liner.
WARNING
DO NOT ATTEMPT TO LIGHT ANY GAS APPLIANCE IF YOU ARE
NOT CERTAIN OF THE FOLLOWING:
x Liquefied petroleum gases/propane gas and natural gas
have an odorant added by the gas supplier that aids in the
detection of the gas.
x Most people recognize this odor as a “sulfur” or “rotten egg”
smell.
x Other conditions, such as “odorant fade” can cause the
odorant to diminish in intensity, or “fade”, and not be as
readily detectable.
x 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
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 contact
(especially by children) with 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
IMPORTANT
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 supplier where
the water heater was purchased or the
manufacturer listed on the rating plate
for replacement parts.
DANGER
Do not store or use gasoline or other flammable,
combustible, or corrosive vapors and liquids in
the vicinity of this or any other appliance.
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.
3

4
ECO Defender Series
Introduction
The Bradford White ECO-DEFENDER Safety System was designed to resist the ignition of flammable
vapors that can occur outside of the water heater. In addition, the ECO-DEFENDER Safety System is
designed to meet the stringent NOx emissions standards required in the South Coast Air Quality
Management District (SCAQMD) Rule 1121. 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 the water
heaters employing the Bradford White ECO-DEFENDER Safety System®.
How the Safety System Works
During normal operation, most air for combustion is drawn into the water heater through the openings in the
jacket door. This air travels into the burner venturi, mixing with the gas jet. This air is then mixed with gas
inside the burner and drawn to the burner screen and is efficiently combusted producing Ultra Low NOx
emissions. Additional air is drawn through the openings in the jacket. This air travels down and around the
combustion chamber and enters through holes in the 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 combustion products
from the burner.
In the case where trace amounts of flammable vapors are present in the air flowing into the combustion
chamber and burner venturi, the vapors are harmlessly ignited by the burner pilot flame. If flammable vapors
are in sufficient quantity to prevent normal combustion, the burner and pilot flames are designed to shut
down.
Should the flammable vapors continue to the burner, the flame arrestor plate and burner screen prevent the
flames from traveling backwards and igniting vapors outside of the combustion chamber. This causes the
thermopile to overheat and shuts down the main pilot and burner. The thermopile powers the intelligent
diagnostic control which is capable of recognizing restricted airflow conditions caused by severe lint, dust
and oil accumulation on the burner screen and arrestor plate. The intelligent diagnostic control will
deactivate the burner and pilot in the unlikely event of restricted airflow.
4

5
ECO Defender Series
It is intended for this manual to be used by qualified service personnel for the primary purpose of
troubleshooting and repair of the Bradford White ECO-DEFENDER Series water heaters.
The Honeywell WV8860 Gas Control will display status codes in the event of abnormal operation. Status
codes are listed in the troubleshooting chart beginning on page 6 of this service manual. The troubleshooting
chart will also indicate the probable cause for the status code and direct the service professional to a service
procedure to properly diagnose the abnormal operation.
Contact the Bradford White technical support group immediately if diagnosis cannot be made using the
methods described in this service manual.
Tools Required for Service
A liquid “U” tube type or a digital (magnahelic) type can be used. This
device is used to measure gas and/or air pressure and vacuum.
Manometer:
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.
Multi-Meter:
In some cases, standard multi-meter probes will damage or simply not be
effective to obtain certain voltage and ohm readings. It will be necessary to
have special electronic “pin” type multi-meter probes. These probes are
available at most electronic wholesale outlets.
Electronic Probes:
Used to measure water temperature. An accurate thermometer is
recommended.
Thermometer:
Used to measure water supply pressure. Also used to determine tank
pressure by adapting to the drain valve of the heater.
Water Pressure Gage:
Pipe wrench, channel locks, open end wrenches (3/8”, 7/16”, 1/2”), 12”
crescent wrench, allen wrench set, screw drivers (common & Phillip’s), 1/4”
nut driver, pliers (common & needle nose), socket set, side cutters, wire
cutters, wire strippers, wire crimpers, torpedo level, small shop vacuum,
step ladder, flashlight and 5-gallon pail.
Various Hand Tools:
5

6
ECO Defender Series V1
Observe green LED indicator on
electronic gas control. Status 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 Service Procedure
None (LED not
on or flashing) Pilot assembly is not lit Gas control is not powered. Light Pilot.
If the pilot will not stay lit
replace pilot assembly. If
problem persists, replace
gas control.
One flash and
three second
pause
1. If setpoint knob is in “PILOT”
position then pilot flame is
detected. Turn setpoint knob
to desired setting.
2. If the setpoint knob is
already at the desired
setting, the water heater is
satisfied.
1. Gas control is
powered and waiting
for setpoint knob to
be turned to a water
temperature setting.
2. Water heater is
satisfied and
operating normally.
Normal operation.
LED strobe (two
quick flashes)
and three second
pause
Thermostat calling for heat (no
faults).
Tank temperature
below setpoint of
thermostat.
Normal operation.
LED on
continuously
(solid)
Setpoint knob has been recently
turned to the “OFF” position. Wait
until LED goes out before
attemptin
g
to reli
g
ht.
Setpoint knob was
turned to “OFF”
position.
LED will not go out and the
control will function
normally the is lit.
Two flashes
and three
second pause
Weak pilot signal detected.
System will reset when pilot
flame is sufficient.
1. Thermopile failure.
2. Unstable pilot.
3. Pilot tube block or
restricted.
1. See service procedure IV
2. See service procedure II
3. See service procedure II
Three flashes
and three
second pause
Insufficient water heating.
System will reset.
1. Thermal sensor out
of calibration.
2. Faulty gas control.
Replace gas control.
6

7
ECO Defender Series V1
Observe green LED indicator on
electronic gas control. Status 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 Service Procedure
Four flashes
three second
pause
Excessive tank temperature.
System must be reset.
1. Temperature sensor
out of calibration.
2. Faulty gas control.
Replace gas control
Five flashes
and three
second pause
Temperature sensor fault.
1. Damage to the
temperature sensor.
2. Temperature sensor
resistance out of
range.
1. Verify control is not wet or
physically damaged
2. Turn set point knob to
“OFF” position. Turn set
point knob to “PILOT”
position and light pilot.
3. Replace gas valve if five
flash status persists.
Six flashes
and three
second pause
Chamber temperature sensor out
of specification. Possible short.
1. Chamber
temperature sensor
out of calibration.
2. Possible short.
1. Reset gas control
2. Replace gas control.
Seven flashes
and three
second pause
Gas valve electronic fault
detected.
1. Control needs to be
reset.
2. Control is wet or
physically damaged.
1. Reset gas control
2. Replace gas control.
Eight flashes
and three
second pause
Standing pilot remains on while
setpoint knob is in “OFF”
position.
Pilot valve stuck in
open position. Replace gas control
Ten flashes
and three
second pause.
Insufficient combustion air
detected.
Insufficient
combustion air.
1. Reset gas control
2. Replace gas control.
7

8
ECO Defender Series V2
Observe colored LED indicator on
electronic gas control. Status 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 Service Procedure
None (LED not
on or flashing)
Millivolt power is not
present. Light pilot.
Gas valve is functioning
normally. Gas valve is not
powered. Light pilot.
If the pilot will not stay
lit replace pilot
assembly. If problem
persists, replace gas
control.
One flash every
four seconds
(LED green)
Not an error. Indicates
pilot is lit and main
burner is off.
You can now turn the know
to a desired setpoint
temperature
Normal operation.
One flash every
second
(LED green)
Not an error. Indicates
main valve is open and
main burner is lit.
None. Control will
automatically shut main
burner off when water
temperature reaches the
setpoint temperature.
Normal operation.
Two flashes
(LED yellow)
Low thermopile voltage;
main valve not turned
ON.
Check thermopile and its
connections. Check pilot
flame.
1. See service procedure
IV.
2. See service procedure
II.
3. See service procedure
II.
Four flashes
(LED red)
Temperature cut-out
limit reached.
Check the valves and the
water temperature sensor.
Reduce the water
temperature setpoint.
Thoroughly check
out main valve operation
and water temperature
control before walking
away.
Replace gas control
8

9
ECO Defender Series V2
Observe colored LED indicator on
electronic gas control. Status 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 Service Procedure
Five flashes
(LED red)
Water temperature
sensor failure.
Check water temperature
sensor and its connection
for open circuits, shorts, or
differences in resistance
between the two sensor
elements.
Replace gas control
Six flashes
(LED red)
Door temperature
sensor failure.
Check door temperature
sensor and its connection
for open circuits or shorts.
See service procedure X.
Solid ON
(LED red)
Not an error-indicates
that the control is in
OFF mode.
None; wait until LED turns
off if you want to restart
system.
LED will go out and the
control will function
normally the pilot is lit.
Nine flashes
(LED red)
Tank leakage detected
by accessory module.
Control recovers after
receiving message from
accessory module.
1. Check T&P valve.
2. Check all water fittings.
3. Pressurize and leak test
tank.
Ten flashes
(LED red)
Abnormal combustion
chamber temperature
profile during heating
cycle.
Clean all combustion air
intakes to the appliance.
Clean the burner. Remove
all obstacles that may
restrict air flow to the
burner.
Replace gas control
9

10
ECO Defender Series
Burner Inspection
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.
Gas pressure is out of specification.
Pilot flame not fully
engulfing spark/flame
sensor.
b)
c)
Main burner should light smoothly from
pilot and burn with a blue flame with a
minimum of yellow tips.
Main burner must be free from any
debris accumulation that may affect
burner operation (see burner cleaning
procedure below).
Burner Cleaning
Step 1. Position gas control knob to the
“OFF” position.
Turn off gas supply to water
heater.
Remove outer jacket door and inner door per
service procedure ED-X on page 21.
Disconnect pilot tube (7/16” wrench) and
feedline (3/4” wrench) from gas control.
Disconnect chamber door temperature sensor
from gas control.
Disconnect resettable thermal switch’s white
and red wire leads from gas control.
Remove burner assembly from combustion
chamber.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Step 7.
10

11
ECO Defender Series
Burner Cleaning (cont.)
Step 8. Remove manifold mount from burner
inner door by removing (2) ¼” hex
drive screws.
Step 9. Thoroughly inspect burner surface
area and burner port area. Remove
any loose debris using a stiff brush,
compressed air and/or a shop
vacuum.
Step 10. Unscrew main burner orifice and feedline
from manifold mount. Remove main burner
orifice from feedline (1/2” wrench) inspect
orifice, clean or replace if necessary.
Step 11. Reassemble burner and reinstall into
water heater. Restore gas supply and
check for gas leaks.
To resume operation, follow the
instructions located on the lighting
instruction label or the lighting instructions
located in the installation and operation
manual.
Step 12.
11

12
ECO Defender Series
Pilot Inspection, Testing and
Replacement
Step 1.
Step 2.
Step 3.
Position gas control knob “OFF” position.
Turn off gas supply to water heater.
Remove outer jacket door and inner door per
service procedure ED-X on page 21.
Disconnect pilot tubing nut (7/16” wrench) and
feedline nut (3/4” wrench) from gas control.
Disconnect igniter/flame sense wire from gas control.
Disconnect wire connections to the resettable thermal switch.
Disconnect chamber door thermal sensor from gas control.
Remove burner assembly from combustion chamber.
Remove pilot assembly from burner (1/4” nut driver).
Visually inspect igniter/flame sense wire for damage.
Replace pilot if damage is found.
With a multi-meter set to ohms setting,
check continuity through igniter/flame
sense wire. Replace pilot if no continuity.
Visually inspect igniter/flame sense
electrode for deterioration. Replace
pilot as necessary. Electrode should
not be in contact with pilot hood.
Visually inspect igniter/flame sense
electrode for oxidation build up.
Carefully clean any oxidation using very
fine emery cloth.
Visually inspect pilot tubing for kinks or
cracks. If damage is found, replace
pilot.
Inspect pilot tubing and pilot orifice for
blockage:
Remove ferrule nut from bottom of pilot
assembly (7/16” wrench).
Remove pilot tube and pilot orifice.
Step 4.
Step 5.
Step 6.
Step 7.
Step 8.
Step 9.
Step 10.
Step 11.
Step 12.
Step 13.
Step 14.
Step 15.
a.
b.
c. Inspect pilot tubing and pilot orifice for blockage.
replace as necessary.
Reassemble pilot and install onto burner.
Reinstall burner assembly to water heater.
Restore gas supply and check for gas leaks.
Clean or
Step 16.
Step 17.
Step 18.
Step 19. To resume operation, follow the instructions located on the lighting
instruction label or the lighting instructions located in the installation and
operation manual.
12

13
ECO Defender Series
Line Pressure
The gas control is designed for a maximum
line pressure of 14.0” w.c. and a minimum
line pressure of 1.0” w.c. over the water
heater’s rated manifold pressure (check
rating plate). Line pressure must be
checked with the main burner on and off to
assure proper readings.
Manifold Pressure Testing
(this procedure presumes a maximum
line pressure of 14.0” w.c.)
Step 1. Set the gas control knob to the “OFF”
position.
Remove pressure tap plug and install
1/8” NPT pipe, coupling & pressure
tap.
Connect manometer to pressure tap.
Follow instructions located on the
lighting instructions label and proceed
to light the main burner and observe
manometer reading.
Proper manifold pressure operating
range for Natural Gas is 5.0” ±0.5” w.c.
If pressure is within the range specified
in the previous step, set Gas
Control knob to the “OFF” position,
remove manometer and pressure tap,
and replace pressure tap plug. Check
for gas leaks prior to placing water
heater back into operation by following
the instructions located on the lighting
label, or the lighting instructions
located in the installation and operation
manual.
If gas pressure is outside the
specification noted above, refer to
page 16 to replace gas control.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Step 7.
13

14
ECO Defender Series
Determine Water Temperature Inside Tank
Step 1.
Step 2.
Position gas control knob to the “OFF” position.
Draw approximately 4 gallons of water from the 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).
Compare the measured water temperature with the setting on the gasStep 3.
control.
10°F.
In most instances, they should not differ by more than approx.
WARNING
Stored water may be HOT WHEN PERFORMING THE FOLLOWING STEPS IN
THIS PROCEDURE. Take necessary precaution to prevent personal injury.
14

15
ECO Defender Series
Gas Control Removal from Water Heater
Step 1. Rotate the gas control knob to the
“OFF” position.
Drain the heater to a point below the
gas control level.
Turn off the gas supply to the water
heater and disconnect gas piping from
the gas control.
Disconnect wire harnesses from the
gas control.
Remove the outer jacket burner
access door.
Disconnect main burner feedline, swing counter-clockwise away from gas control.
Disconnect pilot tube from gas control and move away from gas control.
Removal gas control from water heater by rotating counter clockwise. DO NOT
use a wrench on the gas control body, damage to the gas control may occur. If
necessary, use a length of ½” NPT pipe threaded into gas inlet of gas control.
Install new gas control into water heater by rotating clockwise. DO NOT use a
wrench on the gas control body, damage to the gas control may occur. If
necessary, use a length of ½” NPT pipe threaded into gas inlet of gas control.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Step 7.
Step 8.
Step 9.
Step 10. Reattach main burner feedline, pilot tube and all wire harnesses.
Step 11. Reconnect gas supply piping to inlet of gas control.
15

16
ECO Defender Series
Chamber Sensor Testing
Step 1. Rotate the gas control knob to
the “OFF” position.
Step 2. Disconnect the chamber sensor wire
harness from the gas control.
Step 3. Remove the chamber door temperature
sensor from the right side inner door
(Phillips screw driver).
Step 4. Make sure that the ring terminal of the chamber door
temperature sensor is not touching any surface. Using a multi-meter set to the
ohms setting, insert one-meter probe (see caution) into each of the wire
positions (see photo).
Step 5. Measure the ambient air temperature near the sensor. Compare the ambient
temperature range to the expected resistance range on the chart below.
that resistance increases as temperature decreases.
Note
Sensor Resistance at Various Temperatures
Temperature Range (°F) Resistance Range (kOhms)
41-50 279-175
50-59 219-139
59-68 173-112
68-77 137-90
77-86 110-72
86-104 89-59
104-113 73-48
113-122 60-39
122-131 49-32
CAUTION
DO NOT use standard multimeter
probes for this test. Doing so will
damage connector. Use special
pin type electronic probes or
small diameter wire pins inserted
into connector.
16

17
ECO Defender Series
Closed Circuit Thermopile Testing
Step 1. Closed circuit testing is the
preferred method for testing the
thermopile. 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 pilot
button (rotate the gas control knob
to the pilot position, push and hold
in) during this test.
Using a multimeter capable of measuring millivolts, place
on lead of the multi meter on the left side of the wire
harness and place the second lead of the multi meter on
the right side of the wire harness.
If meter reads 300 millivolts or higher, the thermopile is OK.
Step 2.
Step 3. If reading is
below 300 millivolts, replace the pilot assembly per service procedure ED-II
on page 10.
Open Circuit Thermopile Testing
Step 1. Disconnect red thermopile wire from wire harness leading to the gas control.
Disconnect the white thermopile wire from the resettable thermal switch.
Using a multi meter capable of measuring millivolts, connect one lead to
the red thermopile wire and one lead to the white thermopile wire.
Following the lighting instruction label on the heater,
proceed to light the pilot
and allow the heater to
operate for three minutes.
It will be necessary to hold
the gas control knob down
in the “PILOT”
position continuously
throughout this test. A
reading over 400 millivolts
indicates a good thermopile
output. A reading under 400 millivolts indicates a bad thermopile,
replace the pilot assembly per service procedure ED-II on page 10.
Step 2.
Step 3.
WARNING
115 volt potential exposure. Use
caution to avoid personal injury.
17

18
ECO Defender Series
Igniter, Electrode Testing and Replacement
Step 1.
Step 2.
Remove outer jacket door.
Repeatedly depress the igniter button while
viewing the pilot through the sight glass. If a
spark is present, the circuit is OK. If there is
no spark, proceed to step 3.
Remove white wire from igniter. Hold the
igniter lead from the gas control to an
unpainted surface such as the feedline or gas
control and depress the igniter. If there is a
spark, the igniter is OK, the pilot is not
functioning and must be replaced, see service
procedure ED-II on page 10.
Step 3.
18

19
ECO Defender Series
Resettable Thermal Switch Testing and Replacement
Step 1.
Step 2.
Remove outer jacket door.
Disconnect white wire leads from the
resettable thermal switch.
Using a multimeter capable of
measuring continuity (Ohms), place one
probe of the meter on one of the brass
connection tabs of the resettable
thermal switch, and the remaining probe
on the other connection tab.
If continuity is indicated, the switch is
closed, allowing millivolt current to pass.
If continuity is not indicated, the switch
is open, possibly due to an overheating
condition. The switch is designed to
open at predetermined temperatures.
An open switch can be reset by
depressing the red colored button
located at the center of the switch. The
overheating condition must be
determined prior to putting the water
heater back into service.
Step 3.
Step 4.
Step 5.
PROBABLE CAUSE FOR RESETTABLE THERMAL SWITCH
PROBABLE CAUSE CORRECTIVE ACTION
Burner failure
Inspect burner per service
procedure ED
- I on page 8 and
replace burner if
Weak switch or switch out of Replace resettable thermal switch
Flammable vapor incident Replace water heater
19

20
ECO Defender Series
Resettable Thermal Switch Testing and Replacement (cont.)
Step 1. Rotate gas control knob to the
“OFF” position.
Remove outer jacket door.
Disconnect wire leads from
resettable thermal switch.
Remove (2) ¼” hex drive screws
from the manifold mount.
Remove resettable thermal switch from
manifold mount (Phillips screw driver).
Place new resettable thermal switch in place. Be sure contact surface
of resettable thermal switch and manifold mount are free of any debris.
Secure resettable thermal switch into place using screws from step 6.
DO NOT OVER TIGHTEN SCREWS.
Reconnect wire leads from gas valve and thermopile to resettable
thermal switch.
Step 2.
Step 3.
Step 4.
Step 5.
Step 6.
Step 7.
Note: Wire terminations are interchangeable with either resettable
thermal switch connection.
Step 8.
Step 9.
Replace outer jacket door.
To resume operation, follow the instructions located on the lighting
instruction label or the lighting instruction located in the installation and
operation manual.
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