Bradford White Tankless Error Codes (11, 16, 29, 45, EA, EC, C5, E5): Meaning & Fixes

Bradford White's Infiniti tankless water heaters speak three code languages that must never be mixed: the Infiniti L Series uses plain two-digit numbers, the Infiniti GS/GR models use their own two-digit set with hard and soft lock classes (shown flashing as 'Er' codes on the controller), and the Infiniti K Series uses letter codes from its A, C, E and F families. This article covers the verified core of all three: ignition code 11 and overheat code 16 on the numeric platforms, GS/GR codes 29 (condensate trap), 42 (air pressure switch) and 45 (water leak detection), and the K Series flame, flue and valve codes EA, EC, C1, C2, C3, C5 and E5 — the code many people search for as 'E05.' One assigned member, AD, could not be verified in any Bradford White document and is dealt with in the closing section.

Three Infiniti generations, and the hard/soft lock rules that govern resets

Before reading any Infiniti code, identify the platform, because the numbers overlap and the letters exist on only one of them. The Infiniti L Series (the EverHot-derived platform) displays two-digit codes such as 11, 12, 14 and 16, plus the maintenance code LC for scale. The Infiniti GS/GR models display two-digit codes too, but a different set — 29 is a condensate fault there, a number the L Series does not use the same way — and they classify every code as a HARD lock, which stops the unit until the cause is remedied and the lock is cleared with the Power button, or a SOFT lock, which clears itself when the condition is remedied. The GS/GR controller flashes 'Er' with the number and records the ten previous faults, viewable in Installer Mode as history entries from newest to oldest. The Infiniti K Series uses letters: A0–A9 and AA for temperature sensors, C codes for flue, flow and fan conditions, E codes for high-temperature and internal faults, and F codes for control and gas-path faults; its reset is holding the ON/OFF button for more than 3 seconds, and its failure history holds ten codes. Every section below is tagged with its platform, and no meaning should be carried from one platform to another.

Error code 11: ignition failure on the GS/GR and L Series

Code 11 is the rare member that genuinely exists on two Infiniti platforms with the same core meaning: the burner would not ignite. On the GS/GR models Bradford White quantifies it — ignition has failed 10 times, a hard lock — meaning the control exhausted a long sequence of ignition attempts before giving up, so a GS/GR 11 is never a single missed spark; something in the chain is persistently wrong. On the L Series, 11 is worded 'no ignition,' and Bradford White's diagnostic table points first at the gas chain in a specific order: check that the gas is turned on at the water heater, the gas meter, and the gas valve. That ordering is good practice on both platforms: tankless units need high gas flow at full fire, and a partially open valve or an undersized, sagging supply shows up exactly here. The remaining causes are internal — igniter, flame rod, combustion air — and belong to a licensed technician with a manometer, who will measure inlet gas pressure static and under load rather than guessing. Owner work stops at the external gas chain, clear intake/exhaust terminations, and one reset (Power button on GS/GR after the cause is remedied). A repeating 11 with gas confirmed usually means the unit lit nothing ten times for a mechanical reason, and no number of resets changes that.

Error code 16: over temperature warning on both numeric platforms

Code 16 is the overheat warning shared — with different thresholds and wording — by the GS/GR and L Series. On the GS/GR it is a hard lock: the operating temperature sensor or the DHW sensor detects water temperature greater than 199 degrees Fahrenheit. On the L Series it is an 'over temperature warning' whose Bradford White remedy list is a tour of the usual suspects: restrictions in the combustion air or exhaust vent terminal, low flow or short-cycling (the burner firing against a trickle of water overheats the exchanger quickly), foreign material in the combustion chamber or exhaust, and a clogged — scaled — heat exchanger. Scale deserves emphasis because it explains most repeat 16s in hard-water areas: mineral insulation on the water side forces the metal and the sensors hotter for the same delivered temperature, until the warning trips on ordinary draws. The fix sequence is therefore physical, not electronic: clear the terminals, verify real flow through the unit, and descale the heat exchanger — a pump-driven flush that owners with the service valves and a kit can do, or a routine technician job. Do not treat a 16 as a sensor nuisance and reset past it; on the GS/GR the same protection family includes the high-limit switch (20) and the burner overheat switch (43), and a unit that overheats after descaling has a flow or combustion problem a technician needs to find.

Error code 29: condensate trap blocked (Infiniti GS/GR)

Code 29 on the GS/GR models is one of the most owner-actionable faults in this article: condensate trap blocked, a hard lock. A condensing tankless unit produces acidic condensate whenever it runs, and that water leaves through a trap and drain line; if the trap or line blocks — with debris, algae growth, a frozen or crushed section of hose, or an airlock from poor routing — condensate backs up until the control shuts the unit down to protect the heat exchanger and vent. Bradford White's own remedy for 29 is written at owner level: check the condensate line and its termination, and check the exhaust vent for blockages, because a blocked exhaust can back condensate up from the other side. The practical checklist is to follow the drain from the trap to where it terminates, confirm it actually drips when the unit fires, clear any trap that can be opened and flushed, and verify the line falls continuously downhill with no sagging loops holding water. Clearing the blockage and pressing the Power button should restore operation, per the hard-lock rule that the cause must be remedied first. A 29 that returns within days means the drain arrangement itself is wrong — an unprimed trap, a shared drain backing up, or a vent slope problem — and that is an installer's fix, not a weekly chore to accept.

Error code 45: water leak detection (Infiniti GS/GR)

Code 45 is the Infiniti GS/GR's leak alarm, and Bradford White's instructions for it are the most direct in the whole table: the unit has detected a water leak, the flow control valve closes automatically to prevent leak damage, and the owner is told to turn the power OFF immediately, turn off (valve off) the water heater, and call a qualified technician. Follow that literally. The automatic valve closure limits the damage, but it does not find the leak: candidates include the plumbing connections at the unit, a failed internal component, a condensate overflow masquerading as a leak, or a leak sensor sitting in water from an unrelated source such as a nearby drain or a sweating cold line. Resist the two temptations this code creates — resetting to see if it was a false alarm, and drying the sensor area and restarting without finding where the water came from. Water inside a gas appliance cabinet is an electrical and corrosion hazard as well as a property hazard. A hard lock, 45 clears with the Power button only after the cause is remedied, and 'remedied' here means the leak is found and repaired, which is why Bradford White routes it straight to a technician. Photograph where the water pooled before anything is moved; the pattern is the technician's best evidence.

Error code 42: air pressure switch fault (Infiniti GS/GR)

Code 42 on the GS/GR models reports the APS — the air pressure switch — in its fault state: Bradford White's table notes the switch is closed in normal operation and open is the fault, and classifies 42 as a hard lock. The switch is the unit's proof that combustion air is moving correctly through the intake, fan and exhaust path; when it reads open, the control will not trust the burn. The causes divide between the air path and the switch itself: blocked intake or exhaust terminations (snow, insects, landscaping against a sidewall vent), a vent run that no longer matches the installation, a failing fan, cracked or condensate-filled sensing tubing, or a switch that has failed open. Owner checks are the terminations — genuinely clear both, because a tankless intake can inhale surprising debris — and then stop. Switch testing involves measuring the pressure/vacuum the fan actually generates against the switch's rating, which is technician work with instruments, and bypassing an air pressure switch to 'test' the unit defeats the proof that exhaust gases are leaving the building; it must never be done, even briefly. A 42 that follows heavy snow or a storm often clears with the termination; a 42 on a clear day with clear vents is a fan-or-switch diagnosis, and the Power-button reset should wait until it is made.

Error codes EA and EC: flame loss on the Infiniti K Series

The K Series reports its flame failures in letters, and EA and EC are a graded pair. EA, per the K service manual, is flame not detected — ionization loss 9 consecutive times; the K I&O words the same code more plainly as ignition failure. Nine consecutive losses means the unit is trying to light (or stay lit) and the ionization signal — the flame rod's proof — keeps failing, with the standard causes: gas supply off or pressure low, a dirty or damaged flame rod, or a failing igniter. EC is the partial version: partial ionization loss 5 times in the service manual's wording, 'flame lost during operation' in the I&O — the flame establishes but drops out intermittently, the signature of a marginal flame rod signal, fluctuating gas pressure, or vent/wind effects disturbing the flame picture. Both reset the documented K way, holding ON/OFF for more than 3 seconds, and both deserve the same discipline: verify gas is on to the unit, check the intake/exhaust and air filter, reset once. The K platform gives the technician a gift here — the P4 information menu shows live data including fan speed and output power, and the failure history holds ten codes — so note whether EA/EC arrive with fan or temperature codes, because a flame loss that tracks a vent problem (C1, C2, CF) is a combustion-air repair, not a flame rod. Repeated EA after a confirmed gas supply is an ionization-circuit diagnosis, technician work.

Error code C5: bypass valve fault (Infiniti K Series)

Code C5 on the K Series is a fault in the bypass valve — the service manual's phrase — which the K I&O renders as the bypass water valve disconnected or damaged. The bypass valve is part of the K unit's water-side temperature control, blending and routing flow inside the appliance; when its actuator disconnects or the valve fails, the control cannot manage outlet temperature as designed and reports C5 rather than delivering unpredictable water. 'Disconnected' is worth taking literally as the first check a technician makes: a disturbed connector after other service, or a harness fault, produces the same code as a failed valve, and the repair differs in cost by an order of magnitude. Owners cannot reach this valve — it is inside the cabinet among the water connections — so owner action is limited to noting the context (recent plumbing work? a leak near the unit? temperature swings before the code?) and performing the ON/OFF reset once after any external cause is addressed. A C5 that persists is valve or actuator replacement, which involves draining the unit's water side; that is licensed work. Its neighbours in the C family frame the same philosophy: C7 (fan not working) and C8 (main water valve disconnected) are also connection-and-component faults the control reports precisely so nobody has to guess which actuator went quiet.

Error codes C1 and C2: flue blockage at startup (Infiniti K Series)

C1 and C2 are defined jointly in the K I&O — both mean flue blockage detected during startup due to insufficient combustion air — and Bradford White publishes one shared remedy that is unusually owner-friendly, so it is worth following exactly: reset the appliance (ON/OFF held more than 3 seconds), check the air and exhaust openings for obstructions, and check the air filter, which a dirty or clogged filter can starve. The manual then draws the line clearly: if gas or air tuning is needed, it is carried out by a qualified technician. Startup is when the control proves the flue before committing to ignition, so a C1/C2 is the unit catching a breathing problem at the safest possible moment. Typical obstructions are the mundane ones — a blocked intake screen, snow or mulch against the termination, a wasp nest in the exhaust — plus the K's own air filter, which owners forget exists. The K Series separates this startup pair from their running counterparts: CE (flue blockage during operation from excessive pressure on the condensate siphon) and CF (flue blockage during operation from insufficient combustion air), so a unit that starts clean but faults mid-cycle is telling a different story — check the condensate siphon for CE. C1/C2 codes that survive clean openings and a clean filter move to fan performance and vent sizing, which is technician diagnosis with the P4 live data (fan speed is item 5d) as evidence.

Error code C3: flow sensor does not detect water (Infiniti K Series)

Code C3 means the K unit's flow sensor does not detect water — the service manual's wording — with the I&O adding the recirculation angle: water recirculation not detected. A tankless control uses flow detection as its firing trigger, so a C3 can present two ways: a genuine no-flow condition (a closed isolation valve, a stopped recirculation pump, an air-locked loop after plumbing work) where the unit correctly refuses to fire into still water, or a flow sensor that has failed or fouled and no longer reports water that is actually moving. The owner's checks follow that split: confirm the hot water actually runs at a tap, that the unit's isolation valves are fully open, and that any recirculation system valves are open; if flow is plainly normal and C3 persists, the sensor is the suspect, and sensor testing or replacement is technician work inside the water path. Context helps the diagnosis — C3 immediately after plumbing or pump work is usually the loop, C3 arriving unprovoked on an untouched system is usually the sensor. Compare the related CA code, which covers the opposite extreme (flow above the unit's maximum, or air in a newly commissioned circuit), and C8, the main water valve disconnected: the K control reports its water path in unusual detail, and reading the exact letter matters more than resetting quickly.

Error code E5 — the code searched as 'E05': heat exchanger overheat lock (Infiniti K Series)

First, the spelling: Bradford White documents this code as E5, not E05, in both the K service manual and the K I&O manual; the zero-padded form circulates on third-party lists but appears in no Bradford White document, which matters when ordering parts or describing the fault. The meaning is serious: the copper heat exchanger gas temperature sensor detects temperature above 392 degrees Fahrenheit, and the appliance is locked — the I&O states the lockout condition in full as the condensing unit flue gas temperature above 428 degrees, or 2 minutes above 392 degrees, with the burner cut off. This is the K platform's hardest thermal protection, and its documented remedy points at the dominant cause: descale the appliance. A scaled heat exchanger cannot move heat into the water efficiently, so flue gas leaves hotter and hotter until the copper exchanger's protection trips; hard water and a skipped flush history are the usual backstory, and the related AA code (flue temperatures high, unit regulating power down) is often the warning that preceded the lock. The reset is the standard K hold of ON/OFF for more than 3 seconds, but resetting an E5 without descaling just re-runs the exchanger into the same wall. After descaling, a returning E5 means the overheat is not scale alone — vent restriction or a sensor fault — and becomes a technician's flue-side diagnosis. Treat E5 as the unit protecting its most expensive component, because that is literally what it is.

Diagnosis order on an Infiniti — and the member code AD, which we cannot verify

Work any Infiniti fault in this order. First, name the platform — L, GS/GR or K — from the unit's documentation, and write the code down exactly, letters included. Second, pull the history before resetting: the GS/GR controller stores ten faults, the K stores ten in its failure history, and the pattern (a lone code versus a family of related codes) chooses the repair. Third, do the external checks every platform shares: gas shutoffs open, intake and exhaust terminations clear, air filter clean (K), condensate line and trap draining (GS/GR 29, K CE), isolation valves open, and — on a 45 — water where it should not be, handled before anything else. Fourth, apply the platform's single documented reset: Power button on GS/GR hard locks after the remedy, ON/OFF held 3 seconds on K, and let soft locks clear themselves. Finally, know the stop lines: gas pressure measurement, gas valves, fans, internal sensors and anything inside the cabinet are licensed technician work. One member of this article's assignment must be reported honestly: the code AD appears in no Bradford White Infiniti document we could check — not the K service manual or I&O, not the GS/GR manuals, not the L Series table. Its only sighting anywhere is a third-party question-and-answer thread, which is not a manufacturer source, so this site publishes no meaning for AD rather than inventing one. If a unit displays AD, photograph the display, read the stored failure history, and give both to a Bradford White technician — the history code is the one that can be acted on.

Key takeaways

• Say the platform when you describe a tankless code — 'code 11' means ignition failure on both the GS/GR and L Series, but '29' is a condensate fault only on the GS/GR, and letter codes exist only on the K.
• On the K Series, write E5, not E05 — Bradford White's manuals use E5, and the padded spelling will slow down any parts or support conversation.
• Hard locks (GS/GR) clear with the Power button only after the cause is fixed, and soft locks clear themselves — a soft lock that keeps returning is a diagnosis, not a reset routine.

Resetting the Bradford White water heater

Each Bradford White system has its own documented reset, and they are not interchangeable. ICON gas control (tank): a TCO trip on TTW models resets by rotating the temperature knob to minimum for at least 6 seconds before returning it to the desired setting, and several sensor/valve faults direct the gas valve reset described in the model's Quick Service Guide; after any knob-OFF, wait until the LED goes out before relighting. eF Series, Honeywell generation: soft lockouts (62, 63) reset in User Mode with the lower right Lockout Reset button, and the control retries by itself 3 times every hour; all other codes are hard lockouts resettable only in Service Mode (Temperature Up + Select for 3 seconds, then Lockout Reset for 3 seconds) — service personnel only. eF ICON HD: soft lockout 110 resets by holding the lower right Reset button 3 seconds in User Mode; hard lockouts such as 80 are Service Mode only. Infiniti GS/GR: hard locks clear with the Power button after the cause is remedied; soft locks clear themselves when the condition clears. Infiniti K: press and hold ON/OFF for more than 3 seconds. One reset after fixing a cause is diagnosis; repeated resets are how a fault becomes damage.

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Facts on this page were checked against manufacturer documentation: bradfordwhitecorp.s3.amazonaws.com · res.cloudinary.com · media.distributordatasolutions.com · bradfordwhitecorp.s3.amazonaws.com · docs.bradfordwhite.com · mans.io · www.manualshelf.com · www.manualshelf.com · homeappliance.manualsonline.com · mans.io · homeappliance.manualsonline.com · manuzoid.com · www.manualshelf.com · www.manualshelf.com · manuals.plus · xrefs.plumbersstock.com · manualmachine.com · mans.io · mans.io · mans.io · mans.io