Code: 123🚿 Bradford White Gas Water Heater

Bradford White Error Code 123: Blower Speed Not Proved, Lockout (Meaning, Causes, Fixes)

Reviewed 2026-10-24 · Based on 3 manufacturer & service sources

What the code means

The combustion blower on Bradford White eF Series heaters with the ICON control reports its speed back to the control board through a PWM (pulse width modulation) signal on the blower modulation harness. If the control can't verify the blower speed it first shows hold code 62, "Fan speed not proved". Bradford White's service manual for its Ultra High Efficiency water heaters with ICON (238-54464-00) says that if blower speed isn't verified from the PWM signal within 5 minutes, code 62 changes from a hold condition to lockout 122 or 123 (listed as "Light-off Rate Proving Failed"). Bradford White's newer ICON HD quick service guides for eF Series 125,000 to 500,000 BTU models define 123 as "Fan speed not proved, purge rate proving failed", say it appears after hold 62 and is stored in Diagnostic History, and list 122 separately as light-off rate proving failed (fan speed not proved, hard lockout). Unlike a soft lockout such as 110, the manual says hard lockouts stay on the display and need a manual reset. Other Bradford White water heater lines use their own code lists, so check the manual for your model.

Likely causes

Safe DIY checks

⚠ Before you start

Unplug the appliance and shut off its gas valve before working on it; never disconnect or alter the gas line. If you smell gas, leave and call your gas utility.

  1. Check outside for blocked intake and exhaust terminals (snow, ice, leaves, nests) and clear them.
  2. Note whether the display showed 62 before 123; that tells a technician the blower speed problem lasted long enough to lock the heater out.
  3. Turn the heater off at its power switch, wait a minute and turn it back on. If 123 comes back, leave it off and call a qualified technician rather than resetting it again.
  4. Bradford White warns that resetting lockout conditions without correcting the malfunction can result in a hazardous condition.
  5. If you smell gas, don't touch any switches; leave and call your gas utility from outside.

🛠 When to call a pro

  • Bradford White says its service procedures are to be performed only by qualified service providers.
  • A technician will check the venting and intake for restrictions and confirm the vent length is within specification.
  • They'll check the blower modulation wire harness at the J2 connection for continuity, measure the resistance of each wire from the terminal ends, and make sure the pin terminals make solid contact, replacing the harness if it's defective.
  • If the harness checks good, Bradford White says to replace the blower or the control module. The blower testing procedure also checks 120 VAC at the blower and its amp draw (about 1.5 to 5.5 amps).

Parts that commonly fix it

Always match the part number to your exact model.

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Combustion blower

Must be the exact part for your model and serial number; a technician should replace it.

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Digital multimeter

Used to check harness continuity and voltage; leave live-voltage tests to a technician.

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Carbon monoxide alarm

Recommended in any home with a gas water heater.

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Sources

  1. Bradford White Service Manual 238-54464-00, Ultra High Efficiency Water Heater with ICON and Integrated Control Systems: error table 62 Fan speed not proved (PWM harness checks, hold changes to lockout 123), 122/123 Light-off Rate Proving Failed (blower speed not verified within 5 minutes; check harness and pin terminals, replace blower or control module), soft vs hard lockouts, reset warning, blower testing procedure
  2. Bradford White Quick Service Guide 238-55958-00, EF Series 125-500K BTU Input, ICON HD System: 62 Fan speed not proved (changes to lockout 123), 123 Fan speed not proved, purge rate proving failed (appears after hold 62, stored in Diagnostic History), check vent/intake restriction and blower modulation harness at J2; possible parts blower, control board
  3. Bradford White Quick Service Guide 238-55603-00, EF Series 125-300k and 400-500k BTU Input, ICON HD Sola Control: 122 Light off rate proving failed (hard lockout), 123 Purge rate proving failed (fan speed not proved)

Last reviewed 2026-10-24. Always confirm against the manual for your exact model number.