BRADFORD WHITE D38T155 Commercial 24 Volt Flue Damper Series Water Heater Instruction Manual

BRADFORD WHITE D38T155 Commercial 24 Volt Flue Damper Series Water Heater

Introduction

It is intended for this manual to be used by qualified service personal 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 simply by resetting the water heater and observing the lighting sequence to determine failure mode. 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-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.

Sequence of Operation

1. Thermostat calls for heat.
   The relay closes on the thermostat board, sending 24 volts from the “COM” terminal of the thermostat board to the flue damper.

2. Flue damper begins to rotate open. Once damper is full open, 24 volts is allowed to continue through damper to the “TH” terminal of ignition module.

3. LED on ignition module illuminates.

4. Trial for ignition (90 second trials, 3 trials with 30 second pause between trials).

5. volts from “MV/PV” terminal, to “MV/PV” terminal of gas valve (common terminal).

6. volts from “PV” terminal, through the ECO located in the lower thermister, to “PV” terminal of gas valve to establish gas flow at pilot.

7. Low current high voltage from “spark” terminal, to generate spark at the pilot and ignite pilot gas flow.

8. Pilot flame proving signal (measured in micro-amps). from the “sense” terminal, to prove pilot flame
   

9. Once pilot flame is proven, sparking will stop.

10. Once sparking stops, 24 volts is sent from “MV” terminal on module, to “MV” terminal on gas valve to establish main burner gas flow. Main burners ignite from the pilot flame.
    The ignition module constantly monitors pilot flame. If pilot flame is lost, pilot and main burner are shut down. After a 30 second purge period, module will attempt to re-light pilot beginning at sequence 4 above.

11. Main burner fires until the thermostat is satisfied. The relay on the thermostat board opens, interrupting 24 volts through the damper and ignition module. Pilot and main burner is turned off.

12. Flue damper rotates to the closed position.

LOCKOUT CONDITION

Ignition module will “lockout” if the pilot can not be lit after 3 ignition trials. The ignition module indicates a lockout condition by the continues flash of the LED located on the module.
Lockout reset is accomplished by interrupting 120 VAC to the unit for at least 5 seconds.

TROUBLESHOOTING

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

SERVICE PROCEDURE D24-I Thermostat Circuit Testing

DANGER
120 volt exposure. To avoid personal injury, use caution while performing this procedure.

CAUTION
Be Careful When Making Voltage Measurements or Jumping Terminals Not to Damage or Deform Connectors or Connector Pins.

This procedure assumes the flue damper is in working order. Be sure damper opens under its own power when the thermostat circuit is by-passed. Damper must be open or removed during this test. Do not force damper open using your hands or tools.

SERVICE PROCEDURE D24-I Thermostat Circuit Testing

Thermister Resistance Testing Upper Thermister

1. Determine resistance value of upper thermister. Test across grey wires. (see photo 9).
2. Draw quart of water off T&P valve. Using a thermometer, determine water temperature.
3. Use table below to verify correct resistance per water temperature measured.

Lower Thermister:

1. Determine resistance value of lower thermister. Test across blue wires. (see photo 10).
2. Draw quart of water off Drain Valve. Using a thermometer, determine water temperature.
3. Use table below to verify correct resistance per water temperature measured.

CAUTION
Be Careful When Making Resistance Measurements Not to Damage or Deform Connectors or Connector Pins.

Thermister Resistance at Various Temperatures

Example: If water temperature is 84°F, then the resistance through the sensor would be 8449 (see shaded area). NOTE: Sensor resistance increases as the temperature falls.

SERVICE PROCEDURE D24-II Pilot Operation Testing

DANGER
120 volt exposure. To avoid personal injury, use caution while performing this procedure.

CAUTION
Be Careful When Making Voltage Measurements or Jumping Terminals Not to Damage or Deform Connectors or Connector Pins.

SERVICE PROCEDURE D24-II Pilot Operation Testing

DANGER
120 volt exposure. To avoid personal injury, use caution while performing this procedure.

CAUTION
Be Careful When Making Voltage Measurements or Jumping Terminals Not to Damage or Deform Connectors or Connector Pins.

SERVICE PROCEDURE D24-IV Main Burner & Pilot
Removal and Inspection

WARNING
Heater components may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury.

Main Burner Removal

1. Step 1. Disconnect (un-plug) water heater from electrical supply.
2. Step 2. Turn “OFF” gas supply to water heater.
3. Step 3. Rotate gas valve control knob to the “OFF” position (see photo 17).
4. Step 4. Disconnect Gas supply line from the gas valve (see photo 17).
5. Step 5. Disconnect wire leads from gas valve (see photo 17).
6. Step 6. Disconnect white flame sense wire & orange ignition wire from Ignition module (see photo 18).
7. Step 7. Remove the two burner rack mounting screws.
8. Step 8. Slide complete burner rack out from heater (see photo 19).
9. Step 9. To install burner, reverse above procedure.

Main Burner Inspection

1. Step 1. Burner tubes should be free of any flue scale or other debris. Clean burner tubes using a stiff brush and/or shop vac. Burner ports should have uniform openings. Replacement is recommended for burners where port area is deteriorated or other unintended openings are present.
2. Step 2. Insure pilot shield is in place (see photo 20).
3. Step 3. Inspect pilot position to insure smooth burner ignition from pilot flame. Pilot should be mounted using the two mounting screws thru the burner support bracket resulting in a level pilot position.

Pilot Burner Removal

1. Step 1. With burner rack removed from heater, disconnect pilot tube connection from gas valve
2. Step 2. Remove the two pilot burner mounting screws securing the pilot and pilot shield in place.
3. Step 3. Remove pilot shield and pilot from burner rack.
4. Step 4. To install pilot burner and pilot shield, reverse above procedure. Be sure to reconnect green ground wire.

Pilot Burner Inspection

1. Step 1. Inspect pilot for the following:
   • Broken or cracked ceramic insulators. If found, pilot must be replaced.
   • Damaged electrode or flame sense wire. If found, pilot must be replaced.
   • Oxidation build-up on flame rod. Clean flame rod or replace pilot as necessary.
2. Step 2. Inspect pilot orifice:
   • Remove 7/16″ ferrule nut from bottom of pilot.
   • Remove pilot tube and orifice from pilot.
   • Inspect pilot tube for blockage. Clean or replace as necessary.
   • Inspect pilot orifice for blockage. Clean or replace as necessary.

WARNING
Heater components may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury.

1. Step 1. Disconnect (unplug) water heater from electrical supply.
2. Step 2. Disconnect venting from draft diverter and remove draft diverter from top of water heater.
3. Step 3. Disconnect flue damper from wire harness and remove flue damper from top of water heater.
4. Step 4. If required disconnect top plumbing connection from top of water heater.
5. Step 5. Remove screws holding jacket head to top of water heater and remove jacket head from top of water heater.
6. Step 6. Remove insulation from top of water heater to expose collector cover.
7. Step 7. Remove screw from side (or top) of collector cover and remove collector cover from water heater.
8. Step 8. Remove flue baffles from heater. Note, it may be necessary to use pliers to loosen and remove baffles from flue tubes.
9. Step 9. Visually inspect flue baffles. Flue baffles should show signs of oxidation, this is normal. If the oxidation has deteriorated any portion of the flue baffle, replacement is recommended. If any restrictors are missing, replacement is recommended.
10. Step 10. Upon completion of inspection or subsequent replacement, reinstall flue baffles into heater.
11. Step 11. Reinstall collector cover and insulation over collector cover.
12. Step 12. Reinstall jacket head, flue damper and draft diverter. Reconnect venting.
13. Step 13. Reconnect plumbing connection to top of water heater if required.

WARNING
Heater components may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury.

1. Disconnect (unplug) water heater from electrical supply.

2. Step 2. Turn “OFF” water supply to water heater.

3. Step 3. Open a near by hot water faucet to relieve tank pressure.

4. Step 4. Connect hose to drain valve of water heater and route to an open drain. Open drain valve and drain approximately 1 gallon of water from the water heater. Close drain valve and disconnect drain hose from water heater.

5. Step 5. Disconnect venting from draft diverter and remove draft diverter from top of water heater.

6. Step 6. Disconnect flue damper from wire harness and remove flue damper from top of water heater.

7. Step 7. If required disconnect top plumbing connection from top of water heater.

8. Step 8. Remove screws holding jacket head to top of water heater and remove jacket head from top of water heater.

9. Step 9. Remove insulation from top of water heater to expose collector cover.

10. Step 10. Remove screw from side (or top) of collector cover and remove collector cover from water heater.

11. Step 11. Locate and remove anode rods from top of water heater (1-1/16 hex socket).

12. Step 12. Visually inspect anode rod. Anode rod should show signs of depletion, this is normal.
    If the depletion is half the original diameter (approximately ¾”), replacement is recommended. If any of the steel core of the anode is exposed, replacement is recommended.

13. Step 13. Upon completion of inspection or subsequent replacement, reinstall anode rods into heater.

14. Step 14. Reinstall collector cover and insulation over collector cover.

15. Step 15. Reinstall jacket head, flue damper and draft diverter. Reconnect venting.

16. Step 16. Reconnect plumbing connection to top of water heater if required.

17. Step 17. Restore water supply and power to water heater.

Generic Parts List

1. Draft Diverter w/Leg Kit.

2. Draft Diverter.

3. Draft Diverter Leg.

4. Damper Outlet Reducer.

5. Flue Damper.

6. Hot Outlet Nipple.

7. Cold Water Inlet Dip Tube.

8. Hex Head Anode. Flue Baffle.

9. Flue Reducer.

10. Flue Core. 1″ x ¾” Reducer Bushing.

11. Nipple T&P Valve.

12. T&P Valve.

13. Cleanout O-Ring.

14. Cleanout Gasket (ASME).

15. Cleanout Access Cover.

16. Cleanout Access Cover (ASME). Cleanout Cover Screw.

17. Cleanout Cover Screw (ASME)

18. Cleanout Jacket Cover.

19. Cleanout Jacket Cover Screw.

20. Burner Assembly Complete.

21. Brass Drain Valve.

22. Cold Water Inlet Nipple (side).

23. Gas Valve Harness.

24. Damper Harness.

25. Lower Thermister.

26. Control Box Assembly Complete.

27. Hot Water Outlet Nipple (side).

28. Upper Thermister.

29. Utility Cover.

30. ASSE Approved Nixing Valve

31. A. Draft Panel.

32. A. Burner Rack.

33. A. Burner Tube.

34. A. Gas Valve.

35. A. Burner Manifold.

36. A. Main Burner Orifice.

37. Pilot Shield.

38. A. Pilot Burner.

39. A. Pilot Orifice.

40. A. Pilot Tubing.

41. A. Pilot Mounting Screw.

42. A. Burner Tube Support.

43. A. Manifold Bracket.

44. A. C-Cane Manifold.

45. A. Manifold Straight.

46. A. Manifold Bracket.

47. A. 90° Street Elbow Black.

48. A. 1″ Down Pipe Nipple Black.

49. A. 1″ 90° Elbow Black.

50. A. 1″ Manifold Ball Valve.

51. A. 1″ Close Nipple Black.

52. A. Pilot Regulator.

53. A. Pilot Solenoid.

54. A. 1/8″ Pipe Plug Black.

55. A. 1″ x 1/8″ Reducer Bushing.

56. A. 1″ pipe Tee Black.

57. A. 1″ Close Nipple Black

58. A. 1″ Union Black.

59. A. 1″ 90° elbow Black.

1. C. Temperature Control Knob.
2. C. Potentiometer Gasket.
3. C. Potentiometer (Temperature Control).
4. C. 7/8″ Snap Bushing.
5. C. Temperature Scale Plate.
6. C. Control Box Panel.
7. C. Terminal Strip.
8. C. Ground Terminal.
9. C. Power Cord train Relief Bushing.
10. C. Power Cord.
11. C. Pilot wire Strain Relief Bushing. 12C. 7/8″ Snap Bushing.
12. C. Transformer.
13. Thermostat Board.
14. Ignition Module.
15. C. Control Box Cover.

Glossary of Terms

• AC Alternating Current
• BTU/H British Thermal Units
• CO Carbon Monoxide
• CO2 Carbon Dioxide
• DC Direct Current
• ECO Energy Cut Off
• GFI Ground fault interrupt
• GPM Gallons per Minute
• Hz Hertz
• LED Light Emitting Diode
• NOx Oxides of Nitrogen
• NPT National Pipe Thread
• PSI Pounds per Square Inch
• VA Volt Amps
• VAC Volts Alternating Current
• W.C. Inches of Water Column
• °C Degrees Centigrade
• °F Degrees Fahrenheit
• UA Micro Amp

WATER HEATERS Ambler, PA For U,S, and Canada field service, contact your professional installer or local Bradford

• White sales representative. Sales/800-523-2931 Fax/215-641-1670 Parts Fax/215-641-2180
• Technical Support/800-334-3393 Fax/269-795-1089
• Warranty/800-531-2111 Fax/269-795-1089
• International:Telephone/215-641-9400 Telefax/215-641-9750 BRADFORD WHITE-CANADA” INC.
• Mississauga, ON Sales/866-690-0961 905-238-0100 Fax/905-238-0105
• Technical Support/800-334-3393

Email
parts@bradfordwhite.com
techserv@bradfordwhite.com
www.bradfordwhite.com

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