Bradford White Water Heater EF100T399E3N2

Service Procedure III — Burner Tube Inspection & Replacement

Turn the main power switch off and unplug the water heater, then turn off the gas supply.

Remove the surround cover, then disconnect the gas connection, PVC venting, wire harness, and silicone tubing from the gas valve.

Disconnect the wire harness from the blower assembly.

Remove the two screws holding the hot surface igniter and flame sensor and carefully remove them (for Direct Spark Ignition models, remove the spark rod bracket screws and spark rod instead).

Remove the four nuts holding the burner transition, lift the blower/gas valve/transition assembly off, and set the gasket aside.

Remove the burner tube from the burner mounting insert.

Service Procedure IX — Spark Rod Gap Inspection and Adjustment (Direct Spark Ignition models)

Remove the combustion system per the Combustion System Removal procedure

Measure the spark gap between the spark rod and burner tube

Is the spark gap within the acceptable range of 3/16 in. to 1/4 in.?

Adjust the spark rod if the gap is out of range

Re-measure the spark gap to confirm it is within 3/16 in. to 1/4 in. after adjustment

Reinstall the combustion system

Check several ignitions to confirm the burner lights smoothly

Service Procedure II — Combustion System Testing

Observe burner operation through the sight glass

Verify minimum gas supply piping size (3/4 in. NPT, or 1 in. NPT for EF100T399) and reconfigure piping if undersized

Confirm static inlet gas pressure is stable between 7 and 14 in. W.C.

Is the static inlet gas pressure stable?

For models with Hot Surface Ignition

Confirm the inlet gas pressure does not drop more than 2 in. W.C. during ignition

Does the igniter glow through the sight glass during warm-up?

Check for 120VAC at the ignition-module igniter terminals

Service Procedure VIII — Flame Sensor Testing & Replacement

WARNING — 120-volt potential exposure; the flame sensor may be too hot to handle, so use caution.

Check for a minimum of 1 microamp during the 1.5-second flame-proving period

Is the flame-sensing circuit okay?

Check for the expected 24VAC at the ignition module/control board flame-establishing terminals

Is 24VAC present at the ignition module/control board flame-establishing terminals?

Call technical support if 24VAC is absent

With the sensor disconnected, check for continuity to ground

Replace the sensor and/or wire lead if continuity to ground is present

Service Procedure XII — Intake Pressure Testing (models prior to serial "CF" only)

Check continuity through the normally closed intake pressure switch if the blower does not energize

Refer to the vent safety switch, exhaust pressure switch, or blower testing procedures if the intake pressure switch is not faulty

Check continuity through the switch if the purge LED does not illuminate within the expected time

Confirm the inlet tube pressure tap reads at least -1.2 in. W.C. using a manometer

Remove the hose from the intake pressure switch and restart the heater to see if the purge LED illuminates

Isolate the heater from the intake vent system and restart again to isolate a switch versus vent-system fault if the purge LED illuminates

Check whether the intake vent system is obstructed and clear any obstruction found

Call technical support if no cause is found