BRADFORD WHITE D38T155 Commercial 24 Volt Flue Damper Water Heater User Manual

BRADFORD WHITE D38T155 Commercial 24 Volt Flue Damper Water Heater

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 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 the root cause of failure.
• Contact Technical support immediately if the 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 an 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, screwdrivers (common & Phillips), long reach (12″) magnetic tip Phillips head screwdriver #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. The 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. The flue damper begins to rotate open. Once the damper is fully open, 24 volts is allowed to continue through the damper to the “TH” terminal of the ignition module.
3. LED on ignition module illuminates.
4. Trial for ignition (90-second trials, 3 trials with 30-second pause between trials). The ignition module simultaneously sends:
   • 1. 24 volts from the “MV/PV” terminal, to the “MV/PV” terminal of gas valve (common terminal).
   • 2. 24 volts from the “PV” terminal, through the ECO located in the lower thermister, 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.
5. Once the pilot flame is proven, sparking will stop.
6. Once the sparking stops, 24 volts is sent from the “MV” terminal on the module, to the “MV” terminal on gas valve to establish the 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.
7. The 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
8. The flue damper rotates to the closed position.

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

WIRING DIAGRAM

TROUBLESHOOTING

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

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 TerminalsNot 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.

Thermister Resistance Testing

• Upper Thermister

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

Lower Thermister

1. Determine the 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 the 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 the 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.

• 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.

• 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.

• 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.

• 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.

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

Main Burner Removal

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

Main Burner Inspection

• 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 has deteriorated or other unintended openings are present.
• Step 2. Ensure the pilot shield is in place (see photo 20).
• Step 3. Inspect the pilot position to ensure smooth burner ignition from the pilot flame. The pilot should be mounted using the two mounting screws thru the burner support bracket resulting in a level pilot position.

Pilot Burner Removal

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

Pilot Burner Inspection

• Step 1. Inspect pilot for the following:
  • a) Broken or cracked ceramic insulators. If found, pilot must be replaced.
  • b) Damaged electrode or flame sense wire. If found, pilot must be replaced.
  • c) Oxidation build-up on the flame rod. Clean flame rod or replace pilot as necessary.
• Step 2. Inspect pilot orifice:
  • a) Remove 7/16″ ferrule nut from the bottom of the pilot.
  • b) Remove the pilot tube and orifice from the pilot.
  • c) Inspect the pilot tube for blockage. Clean or replace as necessary.
  • d) Inspect the 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 precautions to prevent personal injury.
• Step 1. Disconnect (unplug) the water heater from the electrical supply.
• Step 2. Disconnect the venting from the draft diverter and remove the draft diverter from top of the water heater.
• Step 3. Disconnect the flue damper from the wire harness and remove the flue damper from top of the water heater.
• Step 4. If required disconnect top plumbing connection from top of the water heater.
• Step 5. Remove screws holding jacket head to top of water heater and remove jacket head from top of water heater.
• Step 6. Remove insulation from top of water heater to expose collector cover.
• Step 7. Remove screw from side (or top) of collector cover and remove collector cover from water heater.
• Step 8. Remove flue baffles from heater. Note, it may be necessary to use pliers to loosen and remove baffles from flue tubes.
• 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.
• Step 10. Upon completion of inspection or subsequent replacement, reinstall flue baffles into heater.
• Step 11. Reinstall collector cover and insulation over the collector cover.
• Step 12. Reinstall jacket head, flue damper, and draft diverter. Reconnect venting.
• 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
• Step 1. Disconnect (unplug) water heater from electrical supply.
• Step 2. Turn “OFF” water supply to water heater.
• Step 3. Open a near by hot water faucet to relieve tank pressure.
• Step 4. Connect hose to drain valve of the 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.
• Step 5. Disconnect venting from draft diverter and remove draft diverter from top of water heater.
• Step 6. Disconnect flue damper from wire harness and remove flue damper from top of water heater.
• Step 7. If required disconnect top plumbing connection from top of water heater.
• Step 8. Remove screws holding jacket head to top of water heater and remove jacket head from top of water heater.
• Step 9. Remove insulation from top of water heater to expose collector cover.
• Step 10. Remove screw from side (or top) of collector cover and remove collector cover from water heater.
• Step 11. Locate and remove anode rods from top of water heater (1-1/16 hex socket).
• 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.
• Step 13. Upon completion of inspection or subsequent replacement, reinstall anode rods into heater.
• Step 14. Reinstall collector cover and insulation over collector cover.
• Step 15. Reinstall jacket head, flue damper and draft diverter. Reconnect venting.
• Step 16. Reconnect plumbing connection to top of water heater if required.
• 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.
9. Flue Baffle.
10. Flue Reducer.
11. 11. Flue Core.
12. 1″ x ¾” Reducer Bushing.
13.  Nipple T&P Valve.
14. T&P Valve.
15. Cleanout O-Ring.
    • 15A. Cleanout Gasket (ASME).
16. Cleanout Access Cover.
    • 16A. Cleanout Access Cover (ASME).
17. Cleanout Cover Screw.
    • 17A 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.

• 1A. Draft Panel.
• 2A. Burner Rack.
• 3A. Burner Tube.
• 4A. Gas Valve.
• 5A. Burner Manifold.
• 6A. Main Burner Orifice.
• 7A. Pilot Shield.
• 8A. Pilot Burner.
• 9A. Pilot Orifice.
• 10A. Pilot Tubing.
• 11A. Pilot Mounting Screw.
• 12A. Burner Tube Support.
• 13A. Manifold Bracket.
• 14A. C-Cane Manifold.
• 15A. Manifold Straight.
• 16A. Manifold Bracket.
• 17A. 90° Street Elbow Black.
• 18A. 1″ Down Pipe Nipple Black.
• 19A. 1″ 90° Elbow Black.
• 20A. 1″ Manifold Ball Valve.
• 21A. 1″ Close Nipple Black.
• 22A. Pilot Regulator.
• 23A. Pilot Solenoid.
• 24A. 1/8″ Pipe Plug Black.
• 25A. 1″ x 1/8″ Reducer Bushing.
• 26A. 1″ pipe Tee Black.
• 27A. 1″ Close Nipple Black
• 28A. 1″ Union Black.
• 29A. 1″ 90° elbow Black.

• 1C. Temperature Control Knob.
• 2C. Potentiometer Gasket.
• 3C. Potentiometer (Temperature Control).
• 4C. 7/8″ Snap Bushing.
• 5C. Temperature Scale Plate.
• 6C. Control Box Panel.
• 7C. Terminal Strip.
• 8C. Ground Terminal.
• 9C. Power Cord train Relief Bushing.
• 10C. Power Cord.
• 11C. Pilot wire Strain Relief Bushing.
• 12C. 7/8″ Snap Bushing.
• 13C. Transformer.
• 14C. Thermostat Board.
• 15C. Ignition Module.
• 16C. 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
• A/ Micro Amp

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
• 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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