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Buderus Fault Codes
Select a fault code to see its meaning, common causes and how to fix it.
GB162, GB172 & Logamax codes
- 3A Fault code 3A on Buderus boilers points to a problem with the flue fan (also called the blower). Depending on the… Read more →
- 3C The Buderus 3C fault code (subcode 217) indicates that the boiler's fan or airflow system has failed to perform… Read more →
- 3F The 3F fault code (also displayed as 3F / 273 on some Buderus models) indicates that the burner and fan have been… Read more →
- 3L The 3L fault code (commonly displayed alongside sub-code 214) means the boiler's draft inducer fan failed to operate… Read more →
- 3P The Buderus 3P fault code (also recorded internally as code 216) indicates that the boiler's blower fan is spinning at… Read more →
- 3Y The Buderus 3Y fault code indicates that the boiler's fan is operating outside its expected speed range — either… Read more →
- 4C Fault code 4C on a Buderus boiler signals that one or both of the built-in safety temperature limiters (STBs) —… Read more →
- 4U The Buderus 4U fault code indicates that the boiler's flow temperature sensor (NTC thermistor) has developed a short… Read more →
- 4Y Fault code 4Y on a Buderus boiler indicates that the flow temperature sensor has developed an open-circuit fault — in… Read more →
- 6A Fault code 6A on a Buderus boiler means the boiler attempted to light the burner but failed to detect a flame. After… Read more →
- 6C The 6C fault code on Buderus boilers is a safety shutdown triggered when the boiler's control electronics detect a… Read more →
- 6L Fault code 6L on a Buderus boiler indicates that the flame-sensing (ionisation) electrode has failed to detect a stable… Read more →
- 7L The 7L fault code on a Buderus boiler signals a timing failure during the very first stage of the ignition sequence.… Read more →
- 8Y The 8Y fault code on a Buderus boiler indicates that the AT90 temperature monitoring relay has triggered a safety… Read more →
- 9L The 9L fault code indicates that the boiler's UBA (Universal Burner Automation — the main control board) has detected… Read more →
- 9P The 9P fault code appears when the boiler's UBA 3 burner control board is unable to communicate with or identify the… Read more →
- EL The EL fault code on a Buderus boiler signals a problem with either the KIM (Boiler Identification Module) or the main… Read more →
- H11 The H11 code appears on Buderus boilers — including the GB072-24K — when the control system detects a problem with the… Read more →
GB142 (UBA-3 sub-codes)
- 0Y 276 Fault code 0Y 276 tells you that the boiler's flow temperature sensor has recorded water temperatures above 95°C,… Read more →
- 0Y 277 The Buderus 0Y fault code (displayed as '0Y 277' on many Buderus controllers) tells you that the boiler has detected a… Read more →
- 0Y 285 The 0Y code appears on Buderus boilers when the internal flow temperature has climbed above its permitted threshold —… Read more →
- 1L 211 The Buderus 1L 211 is a hard lockout fault — the boiler has shut itself down completely and will not restart until… Read more →
- 2E 207 The Buderus fault code 2E 207 tells you that water pressure inside your sealed heating system has dropped below 0.2 bar… Read more →
- 2F 260 The 2F fault code on Buderus boilers indicates that after the burner fires, either the flow sensor and the safety… Read more →
- 2F 271 Fault code 2F (sub-code 271) appears on Buderus boilers — most commonly the Logamax Plus GB142 series — when the… Read more →
- 2F 277 The 2F / 277 fault is a locking fault, meaning the boiler has shut itself down and will only restart after a manual… Read more →
- 2L 266 When your Buderus boiler displays fault code 2L 266, it means the circulation pump failed to generate the required 50… Read more →
- 2P 212 The Buderus 2P / 212 fault code signals that the boiler's control system has detected the heating flow temperature… Read more →
- 2U 213 The Buderus 2U 213 fault code is made up of two parts: the fault category prefix '2U', which covers heating system… Read more →
- 3A 264 The 3A 264 fault code indicates that the boiler fan has stopped or failed during operation. On Buderus boilers, the… Read more →
- 3C 217 The 3C 217 fault code on Buderus boilers indicates that the combustion air fan is not performing as expected. All '3C'… Read more →
- 3F 273 The 3F 273 code appears on Buderus boilers — most notably the Logamax Plus GB142 series — when the burner and fan have… Read more →
- 3L 214 The Buderus 3L 214 fault code means the boiler's draft inducer fan switched off unexpectedly during the pre-purge… Read more →
- 3P 216 Fault code 3P 216 on a Buderus boiler indicates that the flue fan (blower) is rotating below its required operating… Read more →
- 3Y 215 The 3Y fault code on Buderus boilers indicates that the flue gas blower (fan) is operating above its expected speed… Read more →
- 4A 218 The Buderus 4A fault code indicates that a safety temperature device has triggered a protective shutdown, preventing… Read more →
- 4C 224 The 4C 224 fault code on a Buderus boiler signals that one or both of the boiler's safety temperature limiters (STBs) —… Read more →
- 4C 286 The 4C fault code on a Buderus boiler indicates that one or both of the boiler's safety temperature limiters (STBs)… Read more →
- 4E 278 The 4E fault code, paired with operating code 278, means the boiler's control board (the UBA) has failed a sensor test… Read more →
- 4F 219 The 4F 219 fault code on Buderus boilers is a lockout triggered when the safety temperature sensor detects that the… Read more →
- 4L 220 On Buderus boilers running the EMS (Energy Management System) control platform, fault information is displayed in two… Read more →
- 4P 221 The 4P 221 fault on Buderus boilers (including the Logamax Plus GB142, GB162, and GB172 series) is a blocking or… Read more →
- 4P 227 The 227 sub-code appears alongside the primary fault code 6A (sometimes displayed as 4P on certain control panels) on… Read more →
- 4U 222 The 4U fault code (operating code 222) tells you that the boiler's flow temperature sensor — the NTC thermistor that… Read more →
- 4Y 223 The Buderus 4Y 223 fault indicates that the boiler's flow temperature sensor has developed an open circuit — meaning… Read more →
- 6A 227 Fault code 6A 227 on Buderus boilers signals that the ionisation electrode has failed to confirm a flame is present… Read more →
- 6C 228 The 6C 228 fault code on a Buderus boiler means the control system has shut off the gas supply and switched the burner… Read more →
- 6C 306 The 6C 306 fault code on Buderus boilers (including the Logamax Plus GB062 range) is a safety lockout that triggers… Read more →
- 6L 229 The Buderus 6L fault code means the boiler's UBA (Universal Burner Adapter) control board has detected no ionisation… Read more →
- 6L 306 The 6L fault code (displayed as 6L 306 on models such as the GB142 series, where 306 is the accompanying operating… Read more →
- 6P 269 The 6P fault code on a Buderus boiler indicates that the control board (UBA/PCB) is not receiving the expected signal… Read more →
- 7C 231 The 7C 231 code is a two-part display: '7C' identifies the service category, and '231' is the specific sub-code meaning… Read more →
- 7L 261 The Buderus 7L fault code signals a timing failure during the boiler's ignition startup sequence — specifically, the… Read more →
- 7L 280 The Buderus 7L fault (also displayed as sub-code 280) signals that the boiler has failed to complete its first delay… Read more →
- 8Y 232 The 8Y 232 fault code on Buderus boilers is a blocking error that stops the boiler from firing until the underlying… Read more →
- 9A 235 The Buderus 9A 235 fault code signals that the boiler's UBA (Universal Burner Automatics) control board has detected an… Read more →
- 9H 237 The 9H 237 code is a locking system fault on Buderus condensing boilers. It signals that the boiler's onboard… Read more →
- 9H 267 The Buderus fault display works on a two-code system: the primary code shown on screen is 9H, and pressing the Service… Read more →
- 9H 272 The 9H 272 code is a lockout fault on Buderus boilers, meaning the appliance has shut down and will not restart until… Read more →
- 9L 234 The Buderus 9L 234 code is made up of two parts shown in sequence on the boiler's display: 9L identifies the fault… Read more →
- 9L 238 The 9L fault family on Buderus boilers relates to an electrical problem with the gas valve circuit — specifically, the… Read more →
- 9P 239 The 9P fault code (display value 239) appears on Buderus boilers when the main controller cannot successfully read or… Read more →
- 9U 233 The 9U 233 fault code on Buderus boilers (including the Logamax GB series) is made up of two elements. The '9U' portion… Read more →
- C0 288 The C0 288 is a composite fault code made up of two parts. The 'C0' prefix on Buderus boilers signals a sensor short… Read more →
- C0 289 The C0 289 fault code on Buderus boilers indicates that the boiler's control system has detected a short circuit in the… Read more →
- CA 286 The CA 286 code on a Buderus boiler (notably the 500 series) indicates that the boiler is not entering central heating… Read more →
- CU 240 The designation 'CU 240' does not correspond to a recognised fault code within the Buderus boiler fault-code system.… Read more →
- CY 241 CY 241 is a Buderus EMS system fault that points to a short-circuit condition in the outdoor (ambient) temperature… Read more →
- E 290 On Buderus Logamax series boilers (such as the GB162, GB172, and GB192), fault displays typically combine a primary… Read more →