IBC Boiler Error Codes — Meanings, Causes & Repair in Greater Vancouver

Seeing a fault code on your IBC boiler? This guide explains what the most common IBC boiler error codes mean, what’s safe to check yourself, and when to call HeatLand’s licensed, TSBC-certified gas technicians for IBC boiler repair across Metro Vancouver and the Fraser Valley.

The codes below apply across common IBC models (SL, DC, HC, V-series). Meanings follow IBC’s documented fault codes — always confirm against your unit’s own manual, because exact wording can vary by model, control board and firmware.

How to read IBC boiler error codes

IBC uses two main display styles depending on the controller generation. (1) Touchscreen controllers (V10 / V-10, used on current SL and V-series boilers) display a plain-text error MESSAGE on the touchscreen, e.g. 'Error – Ignition Failure after 3 tries', and use a green/yellow/red status indication. (2) Older block-sensor / Honeywell-type controllers on DC and HC series, and the SFT/SFC controllers, display a short NUMERIC fault code on the main display (e.g. 10, 18, 29) with a flashing fault LED; SFT-199 models use an 'F0xx' format (e.g. F004, F018). After the underlying fault is corrected, the burner is restarted with the Reset button. Some faults are warnings (auto-clearing); others are hard lockouts that require a manual reset.

IBC boiler error codes & what they mean

These are the IBC boiler codes our Greater Vancouver technicians see most. Anything marked pro repair involves gas, electrical, sealed-combustion or control-board work that must be done by a licensed gas technician (TSBC-certified in BC) — never open gas or electrical components yourself.

Code	What it usually means	Common causes	Safe to check yourself
Error – Ignition Failure after 3 tries	Boiler failed to ignite/establish flame after three successive attempts; control goes to lockout (typically ~1 hour) before retrying pro repair	Gas supply off or low gas pressure; Air in gas line after service; Dirty/failed igniter or flame sensor	Confirm the gas shutoff valve to the boiler is open; Confirm other gas appliances work (so gas is on to the home); Check the condensate drain/trap is not clogged or frozen
Error – Water High-Limit Exceeded	Water temperature exceeded the high-limit threshold; boiler enters a hard lockout requiring manual reset pro repair	Circulator not running / seized pump; Air-bound system or closed isolation valves; Low system water / low pressure	Read system pressure on the gauge (typically ~12-25 psi cold); Confirm thermostat is calling for a normal temperature; Check that nearby isolation valves appear open (visual only)
Error – Low Water Cutoff	The Safety and Ignition Module (SIM/SIM+) detected a low-water condition; boiler locks out and must be reset pro repair	Low system water / pressure loss; Leak in piping or fittings; Air in the system	Read the system pressure gauge for low pressure; Look for visible water leaks around the boiler; Press Reset once after pressure is confirmed adequate
Insufficient Water Pressure	Measured system water pressure is below the required minimum (can also indicate a loose pressure-sensor plug) pro repair	System pressure loss / leak; Failed or unseated water-pressure sensor connector (P501); Air in system	Read the system pressure on the gauge; Look for obvious leaks; Press Reset once
Insufficient Air Flow	Controller detected inadequate combustion air flow / fan or air-proving condition (can also indicate a loose sensor connector) pro repair	Blocked or restricted intake/exhaust venting; Fan fault or wiring issue; Unseated sensor connector (P501)	Visually check that outdoor intake/exhaust vent terminals are clear of snow, leaves, or debris; Press Reset once
Loop/Indoor Sensor	Loop (system) or indoor temperature sensor signal is missing or out of range, often a disconnected/unseated sensor plug pro repair	Sensor wiring disconnected or damaged; Unseated connector (P501); Failed sensor	Press Reset once; Confirm thermostat operates normally
Error – Max. Inlet/Outlet Sensor Temp. Exceeded	Inlet or outlet water temperature signal is outside the acceptable operating range (too hot / out of bounds) pro repair	Poor circulation / pump not running; Air-bound system; Failed inlet or outlet temperature sensor	Read system pressure on the gauge; Press Reset once after the unit has cooled
Aux. Interlock 1 or 2	An external safety interlock terminal is open (an external safety/limit device has tripped, or its terminals are open) pro repair	External safety device tripped (e.g., flow switch, external LWCO, limit); Open or disconnected interlock wiring jumper	Press Reset once (do not bypass or remove any safety device)
Unknown Error	Generic/unspecified controller error, commonly caused by a disconnected sensor plug or temperature-sensor input fault pro repair	Unseated sensor/wiring connector; Temperature sensor input fault; Intermittent control fault	Press Reset once; Confirm power to the boiler is on
0	Sensor fault detected after the controller self-check pro repair	Temperature sensor or wiring fault detected at startup	Press Reset once
1	Temperature too high pro repair	Poor circulation / pump not running; Air-bound system; Low water flow through heat exchanger	Read the system pressure gauge; Press Reset once after the unit cools
2	S1 and S2 sensors interchanged (supply and return sensors reversed/wired incorrectly) pro repair	Supply (S1) and return (S2) sensor leads swapped after service	Press Reset once (wiring correction is a service task)
4	No flame signal (no flame detected during start-up) pro repair	Gas off or low gas pressure; Air in gas line; Igniter/flame-sense fault	Confirm gas shutoff to the boiler is open; Confirm other gas appliances work; Check condensate drain is clear
5	Poor flame signal / flame disappears during operation pro repair	Marginal gas pressure; Dirty flame sensor or burner; Combustion/venting problem	Confirm gas is on to the home; Press Reset once
6	Flame detection fault (flame sensed when none should be present / flame-simulation fault) pro repair	Flame-sense circuit or wiring fault; Moisture/shorted flame rod; Gas valve not closing properly	Press Reset once
8	Incorrect fan speed pro repair	Fan fault or wiring/connector issue; Blocked or restricted venting; Debris in fan	Visually confirm outdoor vent terminals are clear of debris/snow; Press Reset once
10, 11, 12, 13, 14	Sensor fault S1 (supply sensor, upper-left of heat exchanger) – open/short/out-of-range, e.g. below 28F or above 246F pro repair	Failed supply (S1) sensor; Damaged or disconnected sensor wiring/connector	Press Reset once
18	Flue gas temperature sensor OPEN – lockout condition pro repair	Open/disconnected flue gas sensor; Sensor wiring fault	Press Reset once
19	Flue gas temperature sensor SHORT – lockout condition pro repair	Shorted flue gas sensor; Sensor wiring fault	Press Reset once
20, 21, 22, 23, 24	Sensor fault S2 (return sensor, lower-left of heat exchanger) – open/short/out-of-range pro repair	Failed return (S2) sensor; Damaged or disconnected sensor wiring/connector	Press Reset once
29, 30	Gas valve relay faulty (short) – lockout condition pro repair	Faulty gas valve relay on the controller; Gas valve or wiring fault	Press Reset once
F000	Heat exchanger temperature sensor S0 is defective pro repair	Failed S0 sensor; Sensor wiring/connector fault	Press Reset once
F002	Temperature too high during DHW (domestic hot water) demand pro repair	Poor DHW flow / scaled heat exchanger; Circulation problem; Sensor fault	Press Reset once after the unit cools
F003	Flue gas temperature is too high pro repair	Scaled or fouled heat exchanger; Combustion/venting issue	Visually check vent terminals are clear; Press Reset once
F004	No flame during start-up pro repair	Gas off or low gas pressure; Air in gas line; Ignition/flame-sense fault	Confirm gas shutoff is open; Confirm other gas appliances work; Check condensate drain is clear
F005	Flame disappears during operation pro repair	Marginal gas pressure; Dirty flame sensor/burner; Venting/combustion issue	Confirm gas is on to the home; Press Reset once
F006	Flame simulation (flame detected when none should be present) pro repair	Flame-sense circuit/wiring fault; Moisture/shorted flame rod; Gas valve not closing	Press Reset once
F007	No or insufficient flame current pro repair	Dirty or misaligned flame sensor; Poor grounding; Marginal combustion	Press Reset once
F008	Incorrect fan speed pro repair	Fan fault or wiring issue; Blocked/restricted venting; Debris in fan	Visually confirm vent terminals are clear of debris/snow; Press Reset once
F009	Internal fault in burner controller pro repair	Controller internal fault; Electrical noise / power issue	Press Reset once; Confirm boiler power supply is on and stable
F010, F011	Sensor fault S0 (heat exchanger sensor open/short/out-of-range) pro repair	Failed S0 sensor; Sensor wiring/connector fault	Press Reset once
F012	Sensor fault S5 pro repair	Failed S5 sensor; Sensor wiring/connector fault	Press Reset once
F013	DHW inlet sensor fault S4 pro repair	Failed DHW inlet (S4) sensor; Sensor wiring/connector fault	Press Reset once
F014	Mounting fault sensor S0 (S0 sensor not properly mounted/positioned) pro repair	S0 sensor loose or improperly seated on heat exchanger	Press Reset once (re-mounting is a service task)
F016	Mounting fault S3 (S3 sensor not properly mounted/positioned) pro repair	S3 sensor loose or improperly seated	Press Reset once (re-mounting is a service task)
F018	Flue and/or air supply duct is blocked pro repair	Blocked or restricted intake/exhaust venting; Snow/ice/debris at vent terminals; Blocked condensate	Visually check outdoor intake/exhaust terminals are clear of debris, snow, or ice; Check condensate drain is not clogged or frozen; Press Reset once
F019	Boiler Memory Module (BMM) fault pro repair	Missing, loose, or failed Boiler Memory Module; Controller/BMM communication fault	Press Reset once
F028	Reset error (too many resets / reset-related fault) pro repair	Repeated manual resets without correcting underlying fault; Persistent recurring fault	Do not keep resetting repeatedly; record the prior fault code and call for service
F029	Gas valve fault pro repair	Gas valve or gas-valve wiring fault; Controller relay fault	Press Reset once
F030	Sensor fault S3 pro repair	Failed S3 sensor; Sensor wiring/connector fault	Press Reset once

IBC boiler codes we get called for most

Error – Low Water Cutoff — The Safety and Ignition Module (SIM/SIM+) detected a low-water condition; boiler locks out and must be reset

Typical causes include low system water / pressure loss; leak in piping or fittings; air in the system. A few things are safe to check yourself (Read the system pressure gauge for low pressure; Look for visible water leaks around the boiler), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes Error – Low Water Cutoff on IBC boilers throughout Greater Vancouver.

Insufficient Water Pressure — Measured system water pressure is below the required minimum (can also indicate a loose pressure-sensor plug)

Typical causes include system pressure loss / leak; failed or unseated water-pressure sensor connector (p501); air in system. A few things are safe to check yourself (Read the system pressure on the gauge; Look for obvious leaks), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes Insufficient Water Pressure on IBC boilers throughout Greater Vancouver.

Error – Water High-Limit Exceeded — Water temperature exceeded the high-limit threshold; boiler enters a hard lockout requiring manual reset

Typical causes include circulator not running / seized pump; air-bound system or closed isolation valves; low system water / low pressure. A few things are safe to check yourself (Read system pressure on the gauge (typically ~12-25 psi cold); Confirm thermostat is calling for a normal temperature), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes Error – Water High-Limit Exceeded on IBC boilers throughout Greater Vancouver.

Insufficient Air Flow — Controller detected inadequate combustion air flow / fan or air-proving condition (can also indicate a loose sensor connector)

Typical causes include blocked or restricted intake/exhaust venting; fan fault or wiring issue; unseated sensor connector (p501). A few things are safe to check yourself (Visually check that outdoor intake/exhaust vent terminals are clear of snow, leaves, or debris; Press Reset once), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes Insufficient Air Flow on IBC boilers throughout Greater Vancouver.

Is it safe to keep running a IBC boiler with a fault code?

Most IBC fault codes put the boiler into a safe lockout for a reason. You can safely check the basics — gas supply on, power on, the thermostat calling for heat, system pressure in the normal range, and the condensate drain not frozen or blocked (a common cause in Vancouver cold snaps) — and restart it once. If the code returns, stop and book a technician. If you ever smell gas, leave the building and call your gas utility’s emergency line or 911 first. If a carbon-monoxide alarm sounds, get everyone out and call 911.

IBC boiler repair across Greater Vancouver

HeatLand has kept Metro Vancouver homes comfortable since 1999. Our licensed, insured technicians diagnose and repair IBC boilers — ignition faults, flame and sensor errors, low-pressure and pump problems, fan and flue faults, and control-board issues — including units we didn’t install. We’re brand-agnostic, carry common parts, and give you an honest repair-or-replace assessment with upfront pricing and a free estimate. If your boiler is beyond economical repair, we’ll show you right-sized, high-efficiency replacement options and the rebates available.

Need it sorted fast? We offer priority emergency boiler repair. Explore Boiler services, browse all boiler error codes by brand, or request a free estimate.

IBC boiler service areas

We repair IBC boilers across Greater Vancouver and the Fraser Valley, including:

IBC boiler error code FAQs

Can I reset my IBC boiler myself?

Yes — power-cycling the reset button once is generally safe after you’ve checked the basics (gas supply on, power on, the thermostat calling for heat, system pressure in the normal range, and the condensate drain not frozen or blocked (a common cause in Vancouver cold snaps)). If the boiler faults again right away, stop and note the code — repeatedly resetting a boiler that keeps locking out can mask a real problem. Call a licensed, TSBC-certified gas technician to diagnose it.

What does the IBC Error – Low Water Cutoff code mean?

On IBC boilers, Error – Low Water Cutoff commonly indicates the safety and ignition module (sim/sim+) detected a low-water condition; boiler locks out and must be reset. Confirm the exact meaning against your unit’s manual — codes can vary by model and series — and have the repair done by a licensed, TSBC-certified gas technician. HeatLand fixes this across Greater Vancouver.

Do you repair IBC boilers you didn’t install?

Yes. HeatLand is brand-agnostic and services IBC boilers throughout Metro Vancouver and the Fraser Valley, whether or not we installed the unit. We carry common parts and give you an honest repair-or-replace assessment.

Is a IBC boiler fault code an emergency?

No heat in cold weather is worth treating urgently. If you ever smell gas, leave the building and call your gas utility’s emergency line or 911 first. If a carbon-monoxide alarm sounds, get everyone out and call 911. For priority boiler repair across Greater Vancouver, call (604) 330-3812.

How much does IBC boiler repair cost in Vancouver?

It depends on the fault. Many IBC codes point to sensors, ignition or pump parts — usually far cheaper than replacement. We give upfront pricing and a free estimate before any work.

More Boiler error-code guides

HeatLand repairs every major boiler brand across Greater Vancouver. More brand guides: