Bradford White UDH-75T-50FR-3N User Manual
Save this manual for future reference
Manual 238-49640-00A
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
ECO-Defender Safety System® Models
UDS140S*FRN
UDS150S*FRN
UDH1504T*FRN
UDH165T*FRN
UDH175S*FRN
UDH50T45FR*N
UDH65T45FR*N
UDH75T50FR*N
(*) Denotes Warranty Years
Ultra Low NOx Direct Vent Water Heaters
UDS / UDH Series
The Bradford White
2
Ultra Low NOx Direct Vent Water Heaters
Table of Contents
Page Service Procedure
Introduction 3 - - -
Trouble shooting Chart 4 - - -
Inner Door Gasket Removal, Inspection, Replacement and Installation 6 I
Thermopile Testing and Replacement 9 II
Pilot Assembly Inspection Cleaning and Replacement 10 III
Igniter, Electrode Testing and Replacement 11 IV
Honeywell Gas Control Testing, Disassembly, and Replacement 20 V
Burner Operation Inspection, Adjustment, Cleaning and Replacement 21 VI
Dip Tube and Anode Inspection and Replacement 23 VII
Generic Parts List 25 - - -
2
INTRODUCTION
3
The new Bradford White UDS and UDH 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 FVIR technology and Ultra
Low NOx emissions.
The UDS and UDH 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 normal operating parameters exists, the gas control diagnostic LED wll
flash a code to positively identify an operational issue.
This service manual is designed to facilitate problem diagnosis and
enhance service efficiency. To further promote quicker service times the
gas valve can be removed and replaced without draining the water heater.
Please read the service manual completely before attempting service on
this new series of direct vent water heaters.
How the Safety System Works
During normal operation, air for the combustion chamber is drawn into
the water heater through the vent pipe from outside your building. The air
travels into the closed combustion chamber. The air then mixes in a
normal manner with supplied gas and is efficiently combusted, producing
Ultra Low NOx emissions.
In the unlikely event trace amounts of flammable vapors are present in the
area surrounding the water heater, the sealed combustion system prevents
the flammable vapors from reaching the ignition source.
3
4
Honeywell Gas Control Troubleshooting Chart
Flammable Vapor Ignition Resistant Water
Heaters
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.
Green LED Indicator
LED Status Control Status Probable Cause
None (LED not on or
flashing
One flash and three
second pause
Two quick flashes
and a three second
pause
LED on continuously
(Solid)
Two flashes and
three second pause
Pilot assembly is not lit
1. If set point knob is in “PILOT”
position then pilot flame is detected.
Turn set point knob to desired setting.
2. If the set point knob is already at
the desired setting, the water heater is
satisfied.
Gas control is calling for heat (no
fault).
Set point knob has been recently
turned to the “OFF” position. Wait
until LED goes out before
attempting to relight
Weak pilot signal detected. System will
reset when pilot flame is sufficient.
.
Gas Control is not powered. Light pilot.
1. Gas Control is powered and waiting
for the set point knob to be turned to a
water temperature setting.
2. Water heater is satisfied and
operating normally.
Tank temperature below set point of
thermostat.
Set point knob was turned to “OFF”
position.
1. Thermopile failure
2. Unstable pilot
3. Pilot tube block or restricted.
Service
Procedure
If the pilot will not stay
lit replace pilot
assembly. If problem
persists replace Gas
Control.
1. Adjust set point knob
to desired setting.
Normal operation.
LED will go out and the
control will function
normally when the pilot
is lit.
1. See service
procedure II
2. See service
procedure III
3. See service
procedure III
Four flashes and
three second pause
Excessive tank temperature. System
must be reset.
1. Temperature sensor out of
calibration
2. Faulty Gas Control
4
1. See service
procedure V
2. See service
procedure V
Honeywell Gas Control Troubleshooting Chart
5
Flammable Vapor Ignition Resistant Water
Heaters
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.
Green LED Indicator
LED Status Control Status Probable Cause
Five flashes and
three second pause
Six flashes and
three second pause
Seven flashes and
three second pause
Eight flashes and
three second pause
Thermostat/well sensor fault.
Water leak detected by accessory
module.
Gas Control electronic fault detected.
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.
Excessive amount of water in drain
pan/water dam.
1. Control needs to be reset.
2. Control is wet or physically
damaged.
Pilot valve stuck in open position.
Service
Procedure
1. See service
procedure V
1. Check T&P valve
2. Check all water
fittings.
3. Pressurize and leak
test tank.
1. Reset Gas Control
2. Replace Gas
Control.
Replace Gas Control.
5
The Bradford White
6
Inner Door Removal Procedure
Step 1. Rotate set point knob of the gas control to the “OFF” position.
Step 2. Turn off the gas supply to the water heater
Step 3. Remove the outer door.
Step 4. Remove the four (4) ¼” hex drive screws holding the
right side inner door in place
SERVICE PROCEDURE I
Inner Door/Gasket Removal, Inspection
Replacement and Reinstallation
Step 5. Remove the three (3) ¼” hex drive screws holding the
left side burner door in place.
¼” Hex Drive Screws at Flange
Area of Inner Door
¼” Hex Drive Screws on Left
Side Inner Door
Step 6. Disconnect the pilot tube from the gas control using a
7/16" wrench. Remove the main burner feedline from
the gas control with a ¾” wrench.
Step 7. Disconnect the spark igniter wire from
the gas control.
Step 8. Remove the burner assembly from the combustion chamber.
tep 9. Fully inspect burner and 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 affected by any of the above, gasket replacement is not required. If replacement is
required, proceed to Inner Door Gasket Replacement Procedure.
¼” Hex Drive Screws Right
Side Inner Door
6
The Bradford White
7
Inner Door/Gasket Removal, Inspection
SERVICE PROCEDURE I
Replacement and Reinstallation
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 10. After inspection of inner door as noted in step 9, completely remove gasket and adhesive residue from
burner and left side inner doors as needed.
Step 11. Use RTV sealant (recommended bead size 1/8") to secure the inner door gasket to the inner door sections
(right & burner). The burner door gasket must be sliced in the location shown on the illustration below in
order to slide the gasket over the burner venturi. Refer to illustration below for proper RTV sealant
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.
Installation of Inner Door With
Gasket.
Step 12. Clean any residual gasket residue or other
debris from combustion chamber surface
before installing the inner door/gasket
assembly.
Step 13. Place the burner door into position first. Tighten
the pilot line nut to the gas control. Tighten the
main burner feedline to the gas control. Use the
¼” hex drive screw without the built-in washer
to secure the right side of the burner door to the
chamber. Use the ¼” hex drive screws with the
built-in washer to secure the left side of the
burner door in place. DO NOT OVER
TIGHTEN SCREWS.
Step 14. Position the fiberglass sock containing the igniter
wire, the pilot tube and the armored thermopile
cable against the inner door flange.
7
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 13, 15 and 16.
If a fastener connection is stripped,
contact the manufacturer listed on the
water heater rating plate.
Page 37
The Bradford White
8
Inner Door/Gasket Removal, Inspection
SERVICE PROCEDURE I
Replacement and Reinstallation
Position fiberglass sock, pilot
tube and armored thermopile
cable against flange.
Step 15. Firmly place right side inner door flange against the burner door flange and secure with two ¼” drive
screws from step 5. DO NOT OVER TIGHTEN SCREWS.
Step 16. 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 1/4” hex drive screws from step 5. DO NOT OVER TIGHTEN
SCREWS. Verify both burner and right sides of the inner door are properly positioned and sealed against
the combustion chamber.
Secure flange with
¼" drive screws.
Verify threaded hole
alignment with slotted
openings in inner door.
Step 17. Reconnect the igniter wire to the gas control
Step 18. Replace outer jacket burner access door.
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.
8
The Bradford White
9
SERVICE PROCEDURE II
Thermopile Testing and Replacement
OPEN CIRCUIT THERMOPILE TESTING
The following test should be performed while the pilot flame is on.
Step 1. Turn knob to pilot position and depress.
Step 2. Continue pressing knob and remove red (+) thermopile wire from the red wire leading from the gas control.
Also remove white (-) thermopile wire from the gas control.
Step 3. Using a multimeter capable of measuring millivolts, connect the positive side of the multimeter to the
red (+) thermopile wire connector. Connect the negative side of the multimeter to the white thermopile
connector.
White (-) thermopile wire
Red (+) thermopile wire
Red gas control wire
Red (+) thermopile wire
White (-) thermopile wire
Normal thermopile operation will be between 350mV - 850mV. If reading is less than 350mV, replacement of pilot
assembly is recommended following SERVICE PROCEDURE III.
Step 4. If thermopile reading is between 350mV - 850mV, remove multimeter and reconnect red (+) thermopile wire
to red wire leading from the gas control. Reconnect white (-) thermopile wire negative (-) terminal on gas
control.
Step 5. Release Gas Control knob and turn to desired setting to resume normal operation.
9
Loading...