Bradford White Water Heater D75T3003N

D24-III Main Burner Operation Testing

Confirm the pilot is lit and that the control board stops sparking once the pilot is lit

Check for 22–27 VAC across control-board pin terminals 5 and 8 with the pilot lit and control not sparking

Replace the control board if voltage is present but the main valve does not open

Disconnect the brown wire lead from the gas valve MV terminal and check for 22–27 VAC across the lead and ground

Repair or replace the wire harness if voltage is absent

Check incoming gas pressure and manifold pressure to the burners

Replace the gas valve if inlet pressure is correct but the burner still will not light

D24-VI Anode Removal and Inspection

Unplug the water heater from its electrical supply and shut off the water supply.

Open a nearby hot water faucet to relieve tank pressure.

Disconnect the venting and remove the draft diverter.

Disconnect the flue damper from the wire harness and remove it.

Is it required to disconnect the top plumbing connection?

Remove the screws holding the jacket head and remove it, using a screwdriver to pry underneath if necessary.

Remove the insulation, and the collector cover if necessary, to access the anode rods.

Remove the collector cover screws, chiseling away foam if needed.

D24-IV Main Burner & Pilot Removal and Inspection

WARNING — Heater components can be hot during this procedure; take precautions to avoid injury.

Unplug the water heater from its electrical supply.

Turn off the gas supply and rotate the gas valve control knob to OFF.

Disconnect the gas supply line and the gas valve wire leads.

Disconnect the white flame-sense wire and orange ignition wire from the control board.

Remove the two burner rack mounting screws and slide the burner rack out of the heater.

To reinstall, reverse the removal steps, then check for gas leaks and verify proper operation.

WARNING — 120-volt exposure; use caution while performing this procedure.

CAUTION — Be careful not to damage or deform connectors or connector pins when making voltage measurements or jumping terminals.

Reset the control by holding the Lockout Reset button for 3 seconds and confirm the board starts the ignition sequence and sparks; replace the control board if it does not.

Confirm there is spark at the pilot; if not, check for a loose or damaged ignition wire, a grounded pilot electrode, or a damaged pilot.

Check for 22–27 VAC across control-board pins 8 and 2, and across the MV/PV and PV wire leads at the gas valve, replacing the control board or repairing the harness as indicated.

Loosen the pilot tubing connection at the gas valve and soap-test for pilot gas flow; check for a clogged or kinked pilot tube or orifice, or tighten the connection and replace the gas valve if inlet pressure is otherwise okay.

Flame rod shorted to ground (error code 57)

D24-I Thermostat Circuit Testing

Unplug or disconnect electrical power to the water heater

Check continuity of the wire harness to the affected sensor

Measure resistance of the wire harness

Is the harness resistance close to 0 ohms?

Check sensor resistance against the sensor resistance table

Is the sensor resistance close to the expected value for the measured water temperature?

Restore power and run the heater through a full heating cycle