Bradford White URG2DV40S*N User manual

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Manual 238‐51635‐00A 3/15
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
URG2DV40S*N
URG2DV50S*N
URG2DV50H*N
ULG2DV50H50*N
(*) Denotes Warranty Years
Ultra Low NOx Direct Vent Water Heaters
UDV Series

The Bradford White

2

UDV Series
Ultra Low NOxDirect Vent Water Heaters
Table of Contents
Page UDV SVC Procedure
Introduction ................................................................................................................................4 ---
How to Use This Manual..........................................................................................................5 ---
Tools Required for Service.......................................................................................................5 ---
Troubleshooting.........................................................................................................................6 ---
Burner Inspection, Cleaning & Replacement .........................................................................8 I
Pilot Testing, Cleaning & Replacement ..................................................................................10 II
Gas Control Testing & Replacement.......................................................................................12 III
Thermopile Testing ...................................................................................................................15 IV
Igniter, Electrode Testing and Replacement ...........................................................................16 V
Inner Door Removal and Replacement ...................................................................................17 VI
Diptube Inspection & Replacement.........................................................................................20 VII
Anode Inspection & Replacement ...........................................................................................21 VIII
Glossary of Terms .....................................................................................................................22 ---
Parts List .....................................................................................................................................23 ---
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UDV Series
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WARNING: Iftheinformation inthese
instructions isnot followed exactly, afireor
explosion may resultcausing property damage,
personal injury, or death.
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.

WHATTODOIFYOUSMELLGAS!
xDonottrytolightanyappliance.
xDonottouchanyelectricalswitch;donotuseany
phoneinyourbuilding.
xImmediatelycallyourgassupplierfromaneighbor'sphone.
Followthegassupplier'sinstructions.
xIf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.

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.
WARNING
DO NOT ATTEMPT TO LIGHT ANY GAS APPLIANCE IF YOU ARE
NOT CERTAIN OF THE FOLLOWING:
xLiquefied petroleum gases/propane gas and natural gas
have an odorant added by the gas supplier that aids in the
detection of the gas.
xMost people recognize this odor as a “sulfur” or “rotten egg”
smell.
xOther conditions, such as “odorant fade” can cause the
odorant to diminish in intensity, or “fade”, and not be as
readily detectable.
xIf 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 ¾” X ¾”
TEMPERATURE AND PRESSURE RELIEF VALVE WILL RELEASE
THE MANUFACTURER FROM ANY CLAIM THAT MIGHT RESULT
FROM EXCESSIVE TEMPERATURE AND PRESSURES.
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
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.
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.
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UDV Series
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Introduction
The new Bradford White UDV water heaters are designed to provide reliable performance with enhanced
standard features. Design features include reliable standing pilot ignition system, enhanced diagnostics,
simplified servicing, certified FVIRtechnology, and Ultra Low NOxemissions.
The UDV water heaters use a combustion system where combustion air is drawn from the outside of the
building. The gas control maintains water temperature and maintains gas flow. If a situation outside of
the normal operating parameters exists, the gas control diagnostic LED will flash a code to identify an
operational issue.
This service manual is designed to facilitate problem diagnosis and enhance service efficiency.
Please read the service manual completely before attempting service on this new series of direct vent
water heaters.
How theSafety System Works
During normal operation, most air for combustion is drawn into the water heater though the openings in
the jacket door. This air travels into the burner venturi, mixing the gas jet. This air is then mixed with gas
inside the burner and drawn into 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 it’s 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 shutdown.
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.
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UDV Series
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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 UDV Series water heaters.
The Honeywell WV8840 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 on page 6 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.
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 cannot be made using the
methods described in this service manual.
Tools Required for Service
Manometer:
Multi-Meter:
Electronic Probes:
Thermometer:
Water Pressure Gage:
Various Hand Tools:
Aliquid “U” tube type or a digital (magnahelic)type can be used. This
device is used to measure gas and/or air pressure and vacuum.
Adigital 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.
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.
Used to measure water temperature. An accurate thermometer is
recommended.
Used to measure water supply pressure. Also used to determine tank
pressure by adapting to the drain valve of the heater.
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 vac, step ladder, flashlight and 5 gallon pail.
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UDV Series
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Observegreen LED indicator on
electronic gas control. Status flash
codes are displayed with athree second
pause before repeating. Check and
repair the system as noted in the
troubleshooting tablebelow.
LED Status Control Status Probable
Cause
Service
Procedure
None (LED not
on or flashing)Pilot assemblyis 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 knobis in “PILOT”
position then pilot flame is detected.
Turn setpoint knobto desired
setting.
2. If the setpoint knobis already at
the desiredsetting,the water
heater is satisfied.
1. Gas control is
poweredandwaiting
for setpoint knobto
be turnedto a water
temperature setting.
2. Water heater is
satisfiedand
operating normally.
Normal operation.
Short flash
once per
second
Gas control is calling for
heat (no fault).
Tanktemperature
belowsetpoint of
thermostat.
Normal operation.
LED on
continuously
(Solid)
Setpoint knobhas been
recentlyturnedto the “OFF”
position. Wait until LED
goes out before attempting
to relight.
Setpoint knobwas
turnedto “OFF”
position.
LED will go out andthe
control will function normally
when the pilot is lit.
Two flashes
andthree
secondpause
Weakpilot signal detected.
Systemwill 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
andthree
secondpause
Insufficient water heating.
Systemwill reset.
1. Thermal sensor
out of calibration.
2. Possible short.
Replace gas control
Four flash,
three second
pause
Excessive tanktemperature.
Systemmust be reset.
1. Temperature
sensor out of
calibration.
2. Faultygas control.
1. See service procedure III
2. See service procedure III
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UDV Series
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LED
Status Control Status ProbableCause Service Procedure
Five flashes
and three
second pause
Temperature sensor
fault.
1. Damage to the
temperature sensor.
2. Temperature sensor
resistance out of range.
See service procedure III
Sixflashes
and three
second pause
Water leakdetected
by accessorymodule.
Excessive amount of
water in drain pan/water
dam.
1. CheckT&Pvalve
2. Checkall water
fittings.
3. Pressurize and leak
test tank.
Seven flashes
and three
second pause
Gas control electronic
fault detected.
1. Control needs to be
reset.
2. Control is wet or
physicallydamaged.
1. Reset gas control
2. Replace gas control.
Eight flashes
and three
second pause
Standingpilot remains
on while setpoint knob
is in “OFF” position.
Pilot valve stuckin open
position. Replace gas control.
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UDV Series
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Burner Inspection
Atperiodic intervals(every 6months) avisual inspection shouldbe made of the pilot and main
burner for proper operation and to assure no debris is accumulating.
Pilot flame shouldbe stable, some causes for an unstablepilot flame are:
a) Water heater vent is less than the allowablevent length.
b) Gas pressure is out of specification.
c) Pilot flame not fullyengulfing spark/flame sensor.
Main burner shouldlight smoothlyfrom pilot and
burn with ablue flame with aminimum 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 the gas control knob in
the “OFF” position.
Step 2. Turn off the gas supplyto the
water heater.
Step 3. Disconnect the igniter wire from
the gas control.
Step 4. Disconnect the red and white
pilot wires from the gas control.
Step 5. Remove the outer jacket door.
Remove the inner doors per
service procedure VI on page 17.
Step 6. Disconnect the pilot tube (7/16”
wrench) from the gas control.
Step 7. Disconnect the main feedline
(3/4”wrench) from the gas
control.
Step 8. Remove the burner assembly
from the combustion chamber.
8

UDV Series
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Burner Cleaning (cont.)
Step 9. Thoroughlyinspect the burner
surface area and the burner
port area and remove any
loose debris.
Step 10. Unscrew the burner feedline
from the main burner inner
door.
Step 11. Remove the main burner
orifice from the feedline
(1/2” wrench).
Step 12. Inspect the orifice, clean or
replace if necessary.
Step 13. Reassemblethe burner and reinstall
into the water heater.
Step 14. Restore the gas supplyand check
for any gas leaks.
Step 15. To resume operation, follow the instructions located on the lighting
instruction label or the lighting instructions located in the installation
and operation manual.
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UDV Series
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
RemoveBurner to Gain Access to thePilot
Step 1. Position the gas control knob in
the “OFF” position.
Step 2. Turn off the gas supplyto the
water heater.
Step 3. Remove the outer jacket door
and inner doors per service
procedure VI on page 17.
Step 4. Disconnect the igniter wire from
the gas control. Disconnect the
red and white pilot wires from the
gas control.
Step 5. Disconnect the pilot tube (7/16”
wrench) from the gas control.
Step 6. Disconnect the main feedline
(3/4”wrench) from gas control.
Step 7. Remove the burner assembly
from the combustion chamber.
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UDV Series
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Pilot Inspection, Testing and Replacement
Step 1. Remove the pilot assemblyfrom the burner
(1/4”nut driver).
Step 2. Visuallyinspect the igniter wire for
damage. Replace pilot if damaged.
Electrode shouldnot be in contact with the
pilot hood.
Step 3. With amulti-meter set to ohms setting,
check continuity through igniter wire.
Replace pilot if no continuity.
Step 4. Visuallyinspect igniter electrode for
oxidation buildup. Carefullyclean any
oxidation using avery fine emery cloth.
Step 5. Visuallyinspect the pilot tubing for kinks or
cracks. Ifdamage is found, replace the
pilot assembly.
Step 6. Inspect the pilot tubing and the pilot orifice
for blockage:
a. Remove the ferrulenut from the bottom of
the pilot assembly(7/16” wrench).
b. Remove the pilot tube and pilot orifice.
c. Inspect the pilot tubing and orifice for
blockage. Clean or replace as necessary.
Step 7. Reassemblepilot and install onto the
burner.
Step 8. Reinstall the burner assemblyinto the
water heater.
Step 9. Restore the gas supplyand check for any
gas leaks.
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.
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UDV Series
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Line Pressure
The gas control is designed for amaximum line pressure of 14.0” W.C. and aminimum
line pressure of 1.0” W.C. over the water heater’s rated manifoldpressure (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 amaximum
line pressure of 14.0” w.c.)
Step 1. Position the gas control knob in the “OFF”
position.
Step 2. Remove the pressure tap plug and install
a1/8” NPT pipe, coupling &pressure tap.
Step 3. Connect amanometer to the pressure
tap.
Step 4. Follow instructions located on the lighting
instruction label and proceed to light the
main burner and observe the manometer
readings.
Step 5. Proper operating range for Natural Gas is
5.0” ±0.5” w.c.
Step 6. Ifpressure is within the range specified in
the previous step, set the Gas Control
knob to the “OFF” position, remove
manometer and pressure tap, and replace
pressure tap plug.
Step 7. 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.
Step 8. Ifthe gas pressure is outside of the
specification noted above, refer to the
“Gas Control Testing and Replacement”
to replace gas control on page 14.
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UDV Series
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ECO(Energy CutOut)
The Honeywell gas control is designed with an ECO device that will reset.
To reset the gas control after an status code (4), turn the gas control knob to the “OFF”
position and wait aminimum of (5) minutes before relighting following the instructions
located on the lighting instruction label or the lighting instructions located in the
installation and operation manual.
Determine Water Temperature InsideTank
Step 1. Position the gas control knob to the “OFF” position.
Step 2. Draw approximately4 gallons of water from the drain valve into acontainer
and discard.
Step 3. Compare the measured water temperature with the setting on the gas
control. Inmost instances, they shouldnot differ by more than approx.
10°F.
WARNING
Stored water may be HOT WHEN PERFORMING THEFOLLOWING STEPSIN
THISPROCEDURE. Take necessary precaution to prevent personal injury.
13

UDV Series
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Gas Control Removal From Water Heater
Step 1. Position the gas control knob in the “OFF” position.
Step 2. Drain the heater to apoint below the gas control level.
Step 3. Turn off the gas supplyto the water heater and disconnect
gas piping from the gas control.
Step 4. Disconnect the igniter wire and the red and white pilot wires
from the gas control.
Step 5. Remove the outer jacket burner access door.
Step 6. Disconnect the pilot tube (7/16” wrench) from the gas
control.
Step 7. Disconnect the main feedline (3/4”wrench) from gas control.
Step 8. Remove gas control from water heater by rotating counter
clockwise. DO NOT use awrench on the gas control body,
damage to the Gas Control may occur. Ifnecessary, use a
length of ½”NPT pipe threaded into the gas inlet of gas
control.
Step 9. Install new gas control into water heater by rotating
clockwise. DO NOT use awrench on the gas control body,
damage to the Gas Control may occur. Ifnecessary, use a
length of ½”NPT pipe threaded into the gas inlet of the gas
control.
Step 10.Reattach the main burner feedline, pilot tube and pilot
wires. Reattach igniter wire.
Step 11.Reconnect gas supplyand check for leaks.
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.
14

UDV Series
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
Closed Circuit Thermopile Testing
Closed circuit thermopiletesting is the preferred method for testing the thermopile.
Step 1. Following the lighting instruction
label on the heater, proceed to light
the pilot and allow to operate for
three minutes. Ifthe pilot will not
stay lit, holdthe pilot button (rotate
the gas control knob to the pilot
position, push and holdin) during
this test.
Step 2. Using amultimeter capableof
measuring millivolts, place one lead
of the multimeter on the left side of
the wire harness and place the
second lead of the multimeter on
the right side of the wire harness.
Step 3. Ifmeter reads 300 millivolts or higher, the thermopileis OK. Ifreading is
below 300 millivolts, replace the pilot assemblyper service procedure II on
pages 10 &11.
Open Circuit Thermopile Testing

Step 1. Disconnect the red and white pilot wires from the gas control.
Step 2. Using amultimeter capableof measuring millivolts, connect one lead to the
red thermopilewire and one lead to the white thermopilewire.
Step 3. Following the lighting instruction label on the heater,
proceed to light the pilot and allow the heater to
operate for three minutes. Itwill be necessary to
holdthegas control knob
down in the“PILOT”position
continuouslythroughout this
test. Areading over 400
millivolts indicates agood
thermopileoutput.
Step 4. Areading under 400 millivolts
indicates abad thermopile, replace
the pilot assemblyper service procedure II on pages 10 &11.
15

UDV Series
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Igniter, ElectrodeTesting and
Replacement
Step 1. Remove the outer jacket door.
Step 2. Repeatedlydepress the igniter button while
viewing the pilot through the flame viewing
window. Ifaspark is present, the circuit is
OK. Ifthere is no spark, proceed to step 3.
Step 3. Remove the white wire from the gas
control’s igniter wire. Holdthe igniter lead
from the gas control to an unpainted
surface such as the feedline and depress
the igniter. Ifthere is aspark, the igniter is
OK. Otherwise, the igniter is not
functioning and the pilot assemblymust be
replaced. See service procedure II on
pages 10 &11.
16

UDV Series
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Inner Door Removal Procedure
Step 1. Position the gas control knob in the “OFF” position.
Step 2. Remove the outer jacket burner access door.
Step 3. Remove the wire clip from the feedline if present.
Step 4. Remove (2) ¼”hex drive screws from the right side inner door.
Step 5. Remove (2) ¼”drive screws from the flange section of the inner door.
Step 6. Remove (3) ¼”drive screws from the left side inner door.
Step 7. Remove the inner doors.
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Step 8. Fullyinspect 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
Ifthe 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
Step 9. After inspection of inner door as noted in step 8, completelyremove gasket and
adhesive residue from right and left side inner doors as needed.
WARNING
Ifthe information inthese instructions isnot followed exactly, a
fire or explosion may resultcausing property damage, personal
injury or death.
17

UDV Series
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Inner Door Gasket Replacement Procedure (cont.)
Step 10. Use RTV sealant (recommended bead size 1/8”) to secure the inner door gasket to
the inner door sections (right &left). Refer to the illustrations on the next page for
proper application. Note the overlap configuration in the flange area of the inner
door. Set the flange section first, this will helpto achieve the proper overlap position.
Installation of Inner Door with Gasket
Step 11. Clean any residual gasket residue or other debris
from combustion chamber surface before
installing the inner door/gasket assembly.
Step 12. Place the left side inner door and burner
assemblyinto position first. Using the (3) ¼”hex
drive screws from step 6, secure left side inner
door in place. DONOT OVER TIGHTEN
SCREWS
Step 13. Position pilot tube and igniter/sensor
wire against left side inner door flange
gasket.
Step 14. Firmlyplace right side inner door flange
against the left side inner door flange
and secure with (2) ¼”hex drive screws
from step 5. DONOT OVER TIGHTEN
SCREWS.
WARNING
Stripped fastener connections
mayallowfor seal breachof
inner door. A seal breachmay
resultinafire or explosion
causingpropertydamage,
personal injuryor death. Do
not over tighten screwsin
steps 12,14 and 15.
18

UDV Series
19
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Installation of Inner Door with Gasket (cont.)
Step 15. Align right side inner door to combustion chamber and verify the fastener
holes of the combustion chamber are aligned with right side inner door
slotted opening. Verify seal integrity around combustion opening.
Secure right side inner door using ¼”hex drive screws from step 4. DO
NOT OVER TIGHTEN SCREWS. Verify both left and right sides of inner
door are properlypositioned and sealed against the combustion
chamber.
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Step 16. Replace outer jacket burner access door.
Step 17. To resume operation follow the instructions located on the lighting
instruction label or the lighting instructions located in the installation and
operation manual.
19

UDV Series
20
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DiptubeInspection & Replacement
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
Step 1. Position the gas control knob in the “OFF” position.
Step 2. Turn off the coldwater supplyto the water heater.
Step 3. Connect ahose to the drain valve of the water heater and route to an open
drain.
Step 4. Open anearby hot water faucet to vent the water heater for draining.
Step 5. Open the drain valve of the water heater and allow the heater to drain to apoint
below the inlet connection nipple.
Step 6. Disconnect the inlet nipplefrom the plumbing system.
Step 7. With an appropriate tool such as apipe wrench, remove the inlet nipple/diptube
from the water heater. Use caution not to damage any pipe threads.
Step 8. Visuallyinspect the inlet nipple/diptube. The inlet nipple/diptube shouldbe free
of cracks and any blockage. Hydrojet slots shouldbe open and free of any
blockage. Any damage such as cracks, restriction due to deformation or
unintentional holes are not fieldrepairableand the inlet nipple/diptube must be
replaced.
Step 9. Upon completion of inspection or subsequent replacement, re-install the inlet
nipple/diptube into the water heater.
Step 10.Connect the nipple/diptube to the plumbing system and resume the water supply
to refill with water.
Step 11.To resume operation, follow the instructions located on the lighting instruction
label or the lighting instructions located in the installation and operation manual.

WARNING
Water Heater components and stored water maybeHOT when performingthe
followingsteps inthisprocedure. Take necessaryprecaution to prevent
personal injury.
20