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

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

The codes below apply across common Buderus models (Logamax plus GB142, GB162, GB192i). Meanings follow Buderus’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 Buderus boiler error codes

Buderus Logamax plus GB-series boilers (GB142, GB162, and the newer GB172/GB192i) use the Bosch UBA3 burner control with a BC10/BC20 basic controller. The display shows a 2-character main code (e.g. 6A, 2E, 4C, 3L, 8Y) for combustion/safety faults, or an A-/H- code (e.g. A01, A11, H07) for EMS controller/sensor faults, paired with a 3-digit UBA3 sub-code (e.g. 227, 224, 207, 306) that pinpoints the exact cause. The combined code (main + sub, such as '6A 227') is what should be quoted to a technician. A flashing code means a LOCKING fault (lockout requiring a manual reset); a steady code is usually a BLOCKING fault that clears on its own once the condition is corrected. Reset is done by pressing the 'Reset' button for about 5 seconds — the display shows 'rE' while resetting. A red LED on the UBA3 corresponds to the displayed fault.

Buderus boiler error codes & what they mean

These are the Buderus 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
— (flashing dash)	Blocking fault: no communication between the UBA3 burner control and the BC10 basic controller (no heating, no DHW) pro repair	Loose or corroded ribbon/connector between BC10 and UBA3; Failed BC10 controller; Failed UBA3 control board	Switch the boiler off at its power switch, wait a minute, and switch it back on; Try a single reset (hold Reset ~5 seconds)
0Y / 276	Locking fault: the flow temperature sensor measured a flow temperature above 203 F (95 C) — overheat pro repair	Insufficient water flow / low system pressure; Seized or air-locked circulator pump; Closed isolation valves or blocked heat exchanger	Check the system pressure gauge is in the normal green band (about 12-22 psi) and top up only if you know how; Confirm radiator/zone isolation valves are open; Allow the boiler to cool, then try a single reset
0Y / 277	Locking fault: the safety temperature sensor measured a flow temperature above 203 F (95 C) — overheat pro repair	Low water flow / low system pressure; Blocked or air-bound circulator; Scaled or blocked heat exchanger	Check system pressure on the gauge and top up only if familiar with the procedure; Let the boiler cool down, then try a single reset
1A / 316	Blocking fault: the flue gas sensor temperature is too high (no heating, no DHW) pro repair	Blocked or restricted flue/condensate path; Fouled or scaled heat exchanger; Low water flow allowing high flue temperatures	Check the condensate drain/trap is clear and not frozen or blocked; Confirm the flue terminal outside is not obstructed; Let the unit cool, then try a single reset
1L / 211	Locking fault: no connection between UBA3 terminals 78 and 50 (external safety interlock open) — no heating, no DHW pro repair	Open external limit / interlock device wired to the boiler; Broken or disconnected interlock wiring/jumper	Confirm the boiler has power and any external thermostat is calling for heat
2E / 207	Locking fault: system (water) pressure is too low — below 3 psi (0.2 bar). No heating, no DHW pro repair	Water lost from the system (leak or recent bleeding); System never properly filled; Faulty pressure sensor	Read the system pressure gauge — it should be roughly 12-22 psi when cold; if very low, top up via the filling loop only if you know the procedure; Look for visible water leaks around the boiler and pipes; Try a single reset once pressure is restored
2F / 260	Locking fault: after burner start-up the flow temperature sensor detected no rise in heating-water temperature pro repair	No water circulation (pump failed/air-locked); Closed valves / no flow path; Misplaced or faulty flow temperature sensor	Check system pressure on the gauge; Confirm isolation valves are open; Try a single reset
2P / 271	Locking fault: the temperature difference between the flow and safety sensors is too high (rapid/uneven heating) pro repair	Low or restricted water flow; Air in the heat exchanger; Sensor fault	Check system pressure on the gauge; Try a single reset
2U / 213	Locking fault: temperature difference between flow and return sensors is more than 122 F (50 C) pro repair	Very low water flow / partial blockage; Seized circulator pump; Sensor fault	Check system pressure on the gauge; Try a single reset
2Y / 281	Locking fault: the pump has stopped or is running without water (dry running) pro repair	Loss of system water/pressure; Air-locked or seized circulator pump; Wiring fault to the pump	Check the system pressure gauge and top up only if you know the procedure; Try a single reset once pressure is normal
3A / 264	Locking fault: the fan tacho (speed feedback) signal failed during operation pro repair	Failing combustion fan or fan tacho; Loose fan wiring/connector; Faulty UBA3 control	Try a single reset; if it returns, the fan needs service
3C / 217	Blocking fault: no airflow detected after a set time (no heating, no DHW) pro repair	Blocked air intake or flue; Failing combustion fan; Disconnected/blocked air-pressure sensing	Confirm the outside flue/intake terminal is clear of snow, leaves or debris; Try a single reset
3F / 273	Operating phase (safety check): the boiler switched off briefly because it had run continuously for 24 hours. Normal self-test; it restarts automatically DIY-checkable	Normal 24-hour continuous-run safety reset (not a defect)	No action needed — the boiler restarts on its own
3L / 214	Blocking fault: no fan tacho signal during the pre-operative or operating phase (no heating, no DHW) pro repair	Failing combustion fan or its tacho sensor; Loose fan connector/wiring; Faulty UBA3 control	Try a single reset; if it persists, the fan needs service
3P / 216	Blocking fault: the fan is running too slowly (no heating, no DHW) pro repair	Worn or failing combustion fan; Obstruction loading the fan; Low supply voltage / wiring fault	Confirm the flue/intake terminal is unobstructed; Try a single reset
3Y / 215	Blocking fault: the fan is running too fast (no heating, no DHW) pro repair	Fan/tacho fault; Control or wiring fault	Try a single reset; if it returns, the fan needs service
4C / 224	Blocking fault: missing bridging cable / jumper between UBA3 terminals 22 and 24 (no heating, no DHW). On some units this code reports the dual temperature-limiter (STB) overheat lockout pro repair	Missing or disconnected jumper/interlock at terminals 22-24; Tripped flue-gas or heat-exchanger temperature limiter (overheat); Low water flow / low system pressure	Check the system pressure gauge is in the normal band; Allow the boiler to cool, then try a single reset
4F / 219	Blocking fault: the safety temperature sensor detected a flow temperature over 266 F (130 C) — overheat pro repair	Severe loss of water flow; Seized pump / closed valves; Faulty safety temperature sensor	Check system pressure on the gauge; Let the boiler cool, then try a single reset
4L / 220	Blocking fault: safety temperature sensor contacts shorted, or sensor detected over 266 F (130 C) pro repair	Shorted safety temperature sensor or wiring; Genuine overheat from low flow	Check system pressure on the gauge; Let the boiler cool, then try a single reset
4P / 221	Blocking fault: the safety temperature sensor contacts have been interrupted (open circuit) pro repair	Broken sensor wire/connector; Failed safety temperature sensor	Try a single reset; if it persists, the sensor/wiring needs service
6A / 227	Ignition lockout: insufficient ionization (flame) current — flashing/locking after an unsuccessful ignition, or blocking after 4 failed start-up attempts. No heating, no DHW pro repair	Gas supply turned off or low gas pressure; Dirty or misaligned ignition/ionization electrode; Condensate blockage or air in gas line	Confirm the gas supply is on and other gas appliances work; Check the condensate drain/trap is clear; Try a single reset (one attempt only — do not repeatedly reset)
6C / 228	Blocking fault: an ionization (flame) current was detected before the burner started — false flame signal (no heating, no DHW) pro repair	Wet/dirty ionization electrode giving a false signal; Faulty gas valve allowing gas before ignition; Control/wiring fault	Try a single reset; if it persists, the unit needs service
6C / 306	Blocking fault: an ionization (flame) current was still measured after the burner shut down — flame not extinguishing properly pro repair	Gas valve not closing fully; Dirty/faulty ionization electrode; Control fault	Try a single reset; if it persists, do not keep restarting — book service
6L / 229	Blocking fault: insufficient ionization current during the operating phase — flame lost while running pro repair	Marginal gas pressure or partial gas starvation; Dirty ionization/flame electrode; Condensate or flue restriction	Confirm the gas supply is fully on; Check the condensate drain is clear; Try a single reset
7C / 231	Blocking fault: the power supply was interrupted during a locking fault (e.g. 4A/4C/4E/4F/4L/4P/4U/4Y) pro repair	Power loss while a safety lockout was active; Original underlying lockout fault still present	Restore power, then try a single reset; Note the original code if it reappears
7L / 261	Blocking fault: the UBA3 burner control is defective (no heating, no DHW) pro repair	Failed UBA3 control board; Severe electrical disturbance	Switch the boiler off and on once; if the code remains, the control needs service
8Y / 232	Operating phase: an external switch contact is open, so heating is paused (no heating). Often a wired external limit/aquastat or accessory contact pro repair	External limit/aquastat or accessory contact open; Broken external control wiring	Confirm any external thermostat/control is calling for heat and is powered
9A / 235	Blocking fault: the UBA3 control or the KIM (boiler ID module) is defective (no heating, no DHW) pro repair	Faulty or unrecognized KIM coding plug; Failed UBA3 control board	Switch off and on once; if the code stays, the unit needs service
9L / 234	Blocking fault: the gas valve contacts have been broken (open circuit to the gas valve) pro repair	Disconnected or broken gas valve wiring/connector; Faulty gas valve coil; Faulty UBA3 control	Try a single reset; if it persists, do not keep retrying — book service
9P / 233	Blocking fault: the UBA3 control or the KIM (boiler coding module) is not recognized / defective pro repair	KIM coding plug missing, loose or unreadable; Failed UBA3 control board	Switch off and on once; if the code remains, the unit needs service
A01 / 810	Locking fault: the boiler water (DHW) does not warm up — DHW priority is cancelled. Possible sensor lead, fill-pump, or continuous-draw/leak issue pro repair	DHW sensor lead broken/shorted or sensor faulty; Continuous hot-water draw or a leak; Fill/charge pump fault	Confirm no hot tap or fixture is stuck running/leaking; Switch the boiler off and on once to reset
A01 / 816	Locking fault: no communication on the EMS bus (no connection to the UBA3/MC10). The heating system stops responding to heat demand pro repair	Overloaded or miswired EMS bus; Faulty UBA3/MC10 module; Loose bus wiring to controls	Switch the boiler off and on once; Try a single reset
A01 / 828	Locking fault: the digital water-pressure sensor is generating a fault (sensor defective). No heating, no DHW pro repair	Faulty digital water-pressure sensor; Loose sensor connector/wiring	Check the system pressure on the gauge for reference; Try a single reset; if it persists, the sensor needs service
A11 / 816	Locking fault: room-temperature sensor / remote-control communication or sensor fault on the EMS controller pro repair	Faulty remote control (RC) room sensor; Loose or miswired control bus; Incorrect controller addressing	Confirm the room thermostat/controller is mounted and powered; Switch off and on once
H07	Operating-phase warning: system (water) pressure is too low — below about 12 psi (0.8 bar). The boiler keeps running but flags low pressure DIY-checkable	Gradual water loss from the system; Recent bleeding of radiators; Small leak	Read the system pressure gauge; if low, top up via the filling loop only if you know the procedure; Look for visible leaks at the boiler and pipework
CA / 286	Blocking fault: the return temperature sensor measured a return temperature above 221 F (105 C) — overheat (no heating, no DHW) pro repair	Very low water flow; Seized pump / blockage; Faulty return temperature sensor	Check system pressure on the gauge; Let the boiler cool, then try a single reset
C0 / 288	Blocking fault: the water-pressure sensor contacts are open or shorted (no heating, no DHW) pro repair	Broken or shorted pressure-sensor wiring; Faulty pressure sensor	Try a single reset; if it persists, the sensor/wiring needs service
CU / 240	Blocking fault: the return temperature sensor contacts have shorted (no heating, no DHW) pro repair	Shorted return-sensor wiring; Faulty return temperature sensor	Try a single reset; if it persists, the sensor needs service
CY / 241	Blocking fault: the return temperature sensor contacts have been interrupted (open circuit). No heating, no DHW pro repair	Broken return-sensor wire/connector; Faulty return temperature sensor	Try a single reset; if it persists, the sensor needs service
EL / 290	Locking fault: the UBA3 control or the KIM (coding module) is defective (no heating, no DHW). Also reported on some units as a BC20/main-controller failure pro repair	Failed UBA3 control board; Faulty/unrecognized KIM coding plug	Switch the boiler off and on once; if the code remains, the control needs service
rE	Status (not a fault): displayed while a reset is being carried out — appears for a few seconds after the Reset button is held for about 5 seconds DIY-checkable	Normal reset in progress	No action needed — wait for the display to return to normal operation

Buderus boiler codes we get called for most

6A / 227 — Ignition lockout: insufficient ionization (flame) current — flashing/locking after an unsuccessful ignition, or blocking after 4 failed start-up attempts. No heating, no DHW

Typical causes include gas supply turned off or low gas pressure; dirty or misaligned ignition/ionization electrode; condensate blockage or air in gas line. A few things are safe to check yourself (Confirm the gas supply is on and other gas appliances work; Check the condensate drain/trap is clear), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 6A / 227 on Buderus boilers throughout Greater Vancouver.

6L / 229 — Blocking fault: insufficient ionization current during the operating phase — flame lost while running

Typical causes include marginal gas pressure or partial gas starvation; dirty ionization/flame electrode; condensate or flue restriction. A few things are safe to check yourself (Confirm the gas supply is fully on; Check the condensate drain is clear), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 6L / 229 on Buderus boilers throughout Greater Vancouver.

2E / 207 — Locking fault: system (water) pressure is too low — below 3 psi (0.2 bar). No heating, no DHW

Typical causes include water lost from the system (leak or recent bleeding); system never properly filled; faulty pressure sensor. A few things are safe to check yourself (Read the system pressure gauge — it should be roughly 12-22 psi when cold; if very low, top up via the filling loop only if you know the procedure; Look for visible water leaks around the boiler and pipes), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 2E / 207 on Buderus boilers throughout Greater Vancouver.

0Y / 276 — Locking fault: the flow temperature sensor measured a flow temperature above 203 F (95 C) — overheat

Typical causes include insufficient water flow / low system pressure; seized or air-locked circulator pump; closed isolation valves or blocked heat exchanger. A few things are safe to check yourself (Check the system pressure gauge is in the normal green band (about 12-22 psi) and top up only if you know how; Confirm radiator/zone isolation valves are open), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 0Y / 276 on Buderus boilers throughout Greater Vancouver.

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

Most Buderus 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.

Buderus boiler repair across Greater Vancouver

HeatLand has kept Metro Vancouver homes comfortable since 1999. Our licensed, insured technicians diagnose and repair Buderus 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.

Buderus boiler service areas

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

Buderus boiler error code FAQs

Can I reset my Buderus 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 Buderus — (flashing dash) code mean?

On Buderus boilers, — (flashing dash) commonly indicates blocking fault: no communication between the uba3 burner control and the bc10 basic controller (no heating, no dhw). 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 Buderus boilers you didn’t install?

Yes. HeatLand is brand-agnostic and services Buderus 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 Buderus 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 Buderus boiler repair cost in Vancouver?

It depends on the fault. Many Buderus 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: