COMMERCIAL 24 VOLT FLUE DAMPER SERIES WATER HEATER Gas Water Heaters 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) Manual 47324A Save this manual for future reference
Table of Contents Page Introduction 3 --- Tool required for service 3 --- Sequence of Operation 4 --- Troubleshooting 5 --- Thermostat Circuit Testing 6 D24-I Pilot Operation Testing 8 D24-II Main Burner Operation testing 10 D24-III Main Burner & Pilot Removal & Inspection 12 D24-IV Flue Baffle Removal & Inspection 14 D24-V Anode Removal & Inspection 15 D24-VI Generic Parts List 16 --- Glossary of Terms 19 --- Page 2 2 eF Service Procedure
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.
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). Ignition module simultaneously sends: 1.
TROUBLESHOOTING CAUTION Use Caution Not to Damage Connectors when making Voltage Measurements or Jumping Terminals DANGER 120 volt exposure. Use Caution To Avoid Personal Injury. 1 Verify Primary and secondary voltage at the transformer (see photo 1) Rear terminals primary (120 VAC) If LED on ignition module is flashing, reset water heater by turning “OFF” power.
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.
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). Upper thermister location (applicable models) 2. Draw quart of water off T&P valve. Using a thermometer, determine water temperature. 9 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.
SERVICE PROCEDURE D24-II Pilot Operation Testing 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. Condition: Pilot will not light, Ignition module LED is “ON” Reset heater by turning power “OFF”. Wait 5 seconds and turn power “ON”.
SERVICE PROCEDURE D24-II Pilot Operation Testing DANGER 120 volt exposure. To avoid personal injury, use caution while performing this procedure. Condition: Pilot lights, no flame signal. Module continues to spark until system “Lock Out”. Main burner will not light. Check for loose or damaged flame sense lead from pilot to module. (see illustration 1). Is flame sense lead okay? CAUTION Be Careful When Making Voltage Measurements or Jumping Terminals Not to Damage or Deform Connectors or Connector Pins.
SERVICE PROCEDURE D24-III Main Burner Operation Testing 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. Condition: Main burner will not light, Ignition module LED is “ON” Ground Is Pilot lit? Disconnect “brown” wire from “MV” location of ignition module. See “pilot will not light” (page 8).
SERVICE PROCEDURE D24-III Main Burner Operation Testing 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. Condition: Main burner short cycle Check gas (line) pressure to the water heater. Minimum line pressure should be 5.5" W.C.
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. Gas Valve Wire Leads Main Burner Removal Gas Valve Control Knob Step 1. Disconnect (un-plug) water heater from electrical supply. Step 2. Turn “OFF” gas supply to water heater. Step 3. Rotate gas valve control knob to the “OFF” position (see photo 17). Step 4.
SERVICE PROCEDURE D24-IV Main Burner & Pilot Removal and Inspection Pilot Shield Pilot Burner Removal Step 1. With burner rack removed from heater, disconnect 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 pilot shield and pilot from burner rack. Step 4. To install pilot burner and pilot shield, reverse above procedure. Be sure to reconnect green ground wire.
SERVICE PROCEDURE D24-V Flue Baffle Removal, Inspection 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. Disconnect venting from draft diverter and remove draft diverter from top of water heater. Step 3. Disconnect flue damper from wire harness and remove flue damper from top of water heater. Step 4.
SERVICE PROCEDURE D24-VI Anode Removal and Inspection 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 water heater and route to an open drain.
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. 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.
Generic Parts List 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.
Generic Parts List 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 BTU/H CO CO2 DC ECO GFI GPM Hz LED NOx NPT PSI VA VAC W.C.
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