Bradford White D-38T-155 User manual

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Manual 47985A
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
For The Bradford White
“D” Series Models:
D38T155
D75T(125,160,300)
D65T(370,399)
D80T(180,199,250)
D80T(425,505)
D100T(199,250)
D80L(399,450,505)
D100L(199,250,270,300)
D100S(199,250)
Gas Water Heaters
COMMERCIAL 24 VOLT FLUE DAMPER
SERIES WATER HEATER WITH HONEYWELL
INTEGRATED CONTROL SYSTEM
®

Table of Contents
Page Service Procedure
Introduction 4 - - -
Tools Required for Service 4 - - -
Sequence of Operation 6 - - -
Troubleshooting 7 - - -
Thermostat Circuit Testing 24 D24-I
Pilot Operation Testing 27 D24-II
Main Burner Operation Testing 30 D24-III
Main Burner & Pilot Removal & Inspection 32 D24-IV
Flue Baffle Removal & Inspection 35 D24-V
Anode Removal & Inspection 36 D24-VI
Generic Parts List 38 - - -
Glossary of Terms 41 - - -
Notes 41 - - -
Page 2
2

FEATURES OF HONEYWELL INTEGRATED CONTROLS SYSTEM
Attractive digital water heater display on control panel for setting and displaying
the temperature setpoint. Pressing temperature up and down buttons changes
the temperature setpoint. Temperature format may be displayed in degrees F or
degrees C.
Single control board with plug in wiring controls temperature, ignition, and flue
damper operation.
Reduced number of parts for servicing and wiring.
Plug in wiring reduces chance of miswiring.
Water heater display will show diagnostic codes in the event the water heater
needs servicing. Aids in diagnosing and servicing the water heater.
Water heater display can show up to 10 previous error codes in the service mode
to further aid in servicing the water heater.
Page 3
3

Tools Required for Service
It is intended for this manual to be used by qualified service personnel for the primary purpose of
troubleshooting analysis and repair of the Bradford White 24 Volt Flue Damper Series Water
Heater. Understanding the sequence of operation section of this manual will contribute greatly to
troubleshooting this product.
Troubleshooting begins by noting the error code, if any, on the water heater control display and
finding the section in this service manual for diagnosing the problem for this error code. This step
by step procedure beginning on page 5 will direct the service provider to a series of test
procedures to determine root cause of failure.
Contact Technical support immediately if diagnosis is not determined using the methods described
in this service manual.
Page 4
Manometer: Two types available, a liquid “U” tube type or a digital (magna-helic)
type. This device is used to measure gas and/or air pressures and
vacuum.
Multi-Meter: 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.
Thermometer: Used to measure water temperature. An accurate thermometer is
recommended.
Water Pressure Gage: Used to measure water supply pressure. Also used to determine tank
pressure by adapting to the drain valve of the heater.
Jumper Leads: A length of wire (12" min.) with alligator clip at both ends.
Various Hand Tools: Pipe wrench, channel locks, open end wrench set, 12" crescent wrench,
Allen wrench set, torx bit set, screw drivers (common & phillips), long
reach (12") magnetic tip phillips head screw driver #2 tip, ¼" nut driver,
pliers (common & needle nose), socket set including a 1-1/16 deep well
socket, wire cutters, wire strippers, wire crimpers, torpedo level, small
shop vac, step ladder, and flashlight.
Introduction
4

Power Supply Dedicated 120 VAC, 60 Hz., 15 A
Current Draw Less than 5 Amps.
Approved Gas Type Natural or Propane. Gas supply must match the gas type listed on the water
heater rating label.
Gas Supply Connection 1" NPT connection to gas valve for 370,000 Btu/hr. and over for natural gas,
¾" NPT for rest. Schedule 40 black iron pipe recommended.
Gas Pressure (Nat. & L.P.) Manifold Pressure: 4.5" w.c. natural gas, 10.0" w.c. L.P. Gas Supply
Pressure: At least 1" above manifold pressure with water heater operating,
14" w.c. maximum.
Venting System Atmospherically Vented, Type B venting system or approved chimney. Follow
current National Fuel Gas Code requirements or in Canada, the Natural Gas
and Propane Installation Code.
Minimum Clearance for Servicing 24" Front Clearance, 20" Top, 6" Sides.
Maximum Water Supply Pressure 150 PSI.
Thermostat Sensor(s) Redundant thermister with 11,900 + or - 0.5% ohms resistance at 70 deg. F.
Sensor inside well for lower sensor. Some models use an additional upper
sensor (w/o well) with same resistance values.
Control Board Honeywell Integrated Control Board for Temperature Control, Flue Damper,
and Ignition Control Functions. Operates on 24 volts AC current from
transformer. Some models use single sensor boards, others use two
sensors.
Control Display Honeywell LCD Control Display with Temperature Setpoint, Format, and Error
Code Display in User Mode, Diagnostic Functions in Service Mode.
Communicates with Control Board.
Transformer 120 VAC Primary, 24 VAC Secondary, 40 VA.
Pilot Intermittent Pilot with Spark Electrode and Flame Sensor monitored by Control
Board.
Flue Damper 24 VAC, 60 Hz., 80 Ma.
Page 5
Specifications
5

1
Thermostat calls for heat.
The control board sends 24 volts from damper terminal #2 on the control plug
to the flue damper.
2Flue damper begins to rotate open. Once the flue damper is fully open, the damper end switch closes and 24 volts
is allowed to continue through damper to damper pin terminal #5.
3
4Once pilot flame is proven, sparking will stop.
Page 6
Sequence of Operation
Trial for ignition (three 90 second ignition trials, with 65 second pauses
between trials).
Control Board simultaneously sends:
1. 24 volts from control pin terminal #8, to “MV/PV”
terminal of gas valve (common terminal).
2. 24 volts from control pin terminal #2, to “PV”
terminal of gas valve to establish
gas flow at pilot.
3. Low current high voltage from “spark”
terminal, to generate spark at the pilot and
ignite pilot gas flow.
4. Pilot flame proving signal (measured in
micro-amps). from the “sense” terminal, to
prove pilot flame.
5Once sparking stops, 24 volts is sent from control pin
terminal #5 on control board, to “MV” terminal on gas valve
to establish main burner gas flow. Main burners ignite from
the pilot flame.
The control board constantly monitors pilot flame through
the flame sensor rod. If pilot flame is lost, pilot and main
burners are shut down. After a 65 second inter-purge
period, the control will attempt to re-light the pilot beginning
at sequence 3 above.
7Main burner fires until the thermostat is satisfied. The control
board interrupts 24 volts through the damper and the gas valve
circuit. Pilot and main burners are turned off.
8Flue damper rotates to the closed position.
WIRING DIAGRAM
LOCKOUT CONDITION
Control board will go into “Soft Lockout” if the pilot cannot be lit
after 3 ignition trials. The water heater display indicates a lockout
condition by showing an error code number (62 or 63) with
“Service Needed” in the display window. Refer to error codes in
the diagnostic section of this Service Manual. In a “Soft Lockout”
condition, the control will wait for 60 minutes and then make 3
more attempts to light the pilot and establish the main burners.
Soft lockout reset is accomplished by depressing the lower right
button under “Reset” for 3 seconds.
If the water heater should reach 200 degrees F, then the high limit
control will shut off the burners and the water heater will go into a
“Hard Lockout”. Error code 65 will be shown in the water heater
display. The control can only be reset in the “service mode”,
which is detailed in the next section of this Service Manual.
6

CAUTION
Use Caution Not to Damage Connectors when making Voltage Measurements or Jumping Terminals
Water Heater Fault: Water heater does not operate
Display Error Code: Water heater display does not operate - blank display
Check main power supply to water
heater - fuse, circuit breaker, plug
receptacle, line cord or wiring to
water heater.
Check to make sure switch on top of
control panel is in the ON position
Verify Primary and Secondary
voltage at the control board.
Voltage at primary pins 1&3 (white and
black wires) should be 110-120. If not,
check Line In pins 1&4. Check line cord
with ohmeter. Replace line cord if
defective.
If there is not 24 volts at Secondary
pins on the control board, check
transformer. Replace transformer
or wire harness.
Does water heater display operate?
Does damper begin to open?
Increase thermostat setting if tank is
warm and make sure the control
display status reads “Heating”.
Check wire connections of
board to display. See
illustration.
With the control cover tilted down,
measure the voltage between red and
black wire pin connections to display.
Voltage should be 24 volts AC
measured at the back of the Control
Display.
If no voltage at Display, check wire
harnesses and voltage at E-com
screw terminals (see photo 5).
Replace display if voltage is present at
display pin terminals. Replace control
board if no voltage is present at E-
com terminals (1&3, white-black wires
and 1&2, white-red wires) to display.
N
Y
See next page
Checking primary voltage to
transformer from board. Pins to
black and white wires.
Checking line voltage to board.
Pins to black and white wires.
Checking secondary voltage from
transformer. Pins to blue and yellow
wires.
Checking transformer voltage, front
terminals are 24 volts, rear terminals
are 120 volts.
Page 7
Troubleshooting
1 2
34
5
7

Does damper blade move to the full
open position?
Error code #55 on display.
Remove damper from heater and
jump black & yellow wires of
heater harness. Refer to photo on
this page.
Does water heater begin to
operate?
Check for debris limiting damper
rotation. If no debris, replace
damper.
Isthere pilot flame? Error code #62 on display. See
“Pilot Will Not Light”.
Does Main Burner operate? Error code #62 on display. See
“Pilot Lights, No Flame Signal”
Does burner continue until
thermostat set point is reached?
See setting display in Service Mode
and displaying temperature
sensors.
Error code #63 on display. See
“Main Burner Short Cycles”.
Does the flue damper rotate to the
fully closed position?
Error code #56 on display.
Check for debris limiting damper
rotation. If no debris, replace
damper
System okay
Damper vane show in open position. If damper
is closed, disconnect from harness and
REMOVE damper from water heater.
Harness shown disconnected from
damper with BLACK and YELLOW
wires jumped.
CAUTION
Use Caution Not to Damage Connectors when making Voltage Measurements or Jumping Terminals
N
YY
N
N
N
N
Y
Y
Y
Y
From previous page
Example of error code shown on control display.
Page 8
SELECT Lockout RESET
Status Servic e Nee ded
Error Code Shown
in Water Heater Display
Troubleshooting
6
8

ACCESSING SERVICE MODE ON THE WATER HEATER DISPLAY (FOR SERVICE PERSONNEL ONLY)
The display has a “service mode” for changing the maximum setpoint and accessing information in aiding servicing of the
water heater. This procedure is for service and installation personnel only. To enter the Service Mode, follow the steps
illustrated below:
Step 1: Press “Select” and “Temperature Up” buttons together and hold for 3 seconds until “Max Setpoint” is shown in the
display.
Step 2: Pressing “Select” button will change display to next mode
SELECT SET
Status
°F
idl
e
Operational
Wate
r
Temp
The following is the sequence of modes available in “Service Mode” by pressing the “Select” button:
Error Code Number (Display/Reset). This is only shown if there is an operating error in the “User Mode”.
"Max Setpoint”
SELECT SET
Statu
s
idle
Operational
next to Temperature
Setpoint value.
Max
Setpoint
SELECT Lockout RESET
Status Service Needed
Error Code Shown
in Water Heater Display
Page 9
Troubleshooting
Using Control Display for Servicing the
Water Heater
9

1. Max Setpoint (Display/Change)
2a. Water Temperature Average (Displays average if there are two sensors - sensor temperature displayed if single
sensor is used).
SELECT SET
Status
°F
idle
Water Temp
Operational
2b. Water Temperature - Upper Sensor (Displays if there is an upper sensor - some models)
SELECT SET
Status
°F
idl
e
Operational
Upper Sensor
2c. Water Temperature - Lower Sensor (Displays if there are two sensors)
SELECT SET
Status
°F
idle
Operational
Lower Sensor
SELECT SET
Status
°F
idl
e
Operational
Max Setpoint value in
Water Heater Display
Max
Setpoin
t
&
Page 10
Troubleshooting
10