Bradford-White D-38T-155 User Manual

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C

IAL 24 VOLT FLUE DAMPER

S ES WATER HEATER WITH HONEYWELL

INT

TED CONTROL SYSTEM

 

Ga r Heate

S ICE

MANUAL

T eshooting Guide

a

structions for Service

 

(To be performed ONLY by

 

qua

ce providers)

 

M

Covered

 

b

 

For The Bradford White “D” Series Models: D38T155

D75T(1

D65T(3

D80T(180,199,250)

D80T(4

D100T(199,250)

D80L(399,450,505)

D100L(199,250,270,300)

D100S(199,250)

M

l 47985A

Save this manual for future reference

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

Introduction

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.

Tools Required for Service

 

 

 

 

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-ampsand 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 1-1/16deep well socket, wire cutters, wire strippers, wire crimpers, torpedo level, small shop vac, step ladder, and flashlight.

Page 4

4

Specifications

Power Supply

Dedicated 120 VAC, 60 Hz., 15 A

 

 

Current Draw

Less than 5 Amps.

 

 

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.

 

 

Approved Gas Type

Natural or Propane. Gas supply must match the gas type listed on the water

 

heater rating label.

 

 

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

5

Sequence of Operation

1

2

3

4

5

7

8

Thermostat calls for heat.

The control board sends 24 volts from damper terminal #2 on the control plug to the flue damper.

Flue 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.

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.

Once pilot flame is proven, sparking will stop.

Once 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-purgeperiod, the control will attempt tore-lightthe pilot beginning at sequence 3 above.

Main 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.

Flue damper rotates to the closed position.

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 WIRING DIAGRAM 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.

Page 6

6

Troubleshooting

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

1

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

Checking line voltage to board. Pins to black and white wires.

Verify Primary and Secondary

voltage at the control board.

If there is not 24 volts at Secondary pins on the control board, check transformer. Replace transformer or wire harness.

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.

3

2

Checking primary voltage to transformer from board. Pins to black and white wires.

4

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”.

Y

See next page

Checking secondary voltage from transformer. Pins to blue and yellow wires.

N

Check wire connections of

 

 

board to display. See

 

 

illustration.

5

Checking transformer voltage, front terminals are 24 volts, rear terminals are 120 volts.

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-comscrew 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-blackwires and 1&2,white-redwires) to display.

Page 7

7

Troubleshooting

CAUTION

Use Caution Not to Damage Connectors when making Voltage Measurements or Jumping Terminals

From previous page

Does damper blade move to the full open position?

Y

Is there pilot flame?

Y

Does Main Burner operate?

Y

Does burner continue until thermostat set point is reached? See setting display in Service Mode and displaying temperature sensors.

Y

Does the flue damper rotate to the fully closed position?

Y

System okay

 

Error code #55 on display.

 

 

 

N

Remove damper from heater and

 

Does water heater begin to

 

jump black & yellow wires of

 

 

 

operate?

 

heater harness. Refer to photo on

 

 

 

 

 

 

this page.

 

 

Y

 

 

 

 

 

 

 

N

Error code #62 on display. See

 

Check for debris limiting damper

 

 

 

“Pilot Will Not Light”.

 

rotation. If no debris, replace

 

 

 

damper.

N

Error code #62 on display. See

 

 

 

 

 

 

 

 

“Pilot Lights, No Flame Signal”

 

 

 

N

Error code #63 on display. See

 

 

“Main Burner Short Cycles”.

Error code #56 on display.

N Check for debris limiting damper rotation. If no debris, replace

damper

Damper vane show in open position. If damper is closed, disconnect from harness and REMOVE damper from water heater.

6

Harness shown disconnected from damper with BLACK and YELLOW wires jumped.

Error Code Shown

in Water Heater Display

Status Service Needed

SELECT Lockout RESET

Example of error code shown on control display.

Page 8

8

Troubleshooting

Using Control Display for Servicing the

Water Heater

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. "Max Setpoint”

next to Temperature Setpoint value.

Max

Setpoint

idle

Statu Operational s

SELECT SET

Step 2: Pressing “Select” button will change display to next mode

°F Water

Temp

idle

Status Operational

SELECT SET

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”.

Error Code Shown

in Water Heater Display

Status Service Needed

SELECT Lockout RESET

Page 9

9

 

 

Troubleshooting

1. Max Setpoint (Display/Change)

 

Max Setpoint value in

 

 

Water Heater Display

°F

Max

 

 

Setpoint

 

idle

 

 

Status Operational

 

 

2a. Water Temperature Average (Displays&average ifSELECTthere are twoSET

sensors - sensor temperature displayed if single

sensor is used).

 

 

°F Water Temp

idle

Status Operational

SELECT

SET

2b. Water Temperature - Upper Sensor (Displays if there is an upper sensor - some models)

°F

idle

Status Operational

Upper Sensor

SELECT SET

2c. Water Temperature - Lower Sensor (Displays if there are two sensors)

°F

idle

Status Operational

Lower Sensor

SELECT

SET

Page 10

10