Welcome to the Maintracts Services blog, your trusted source for all your ATG boiler needs! With over four decades of experience since our establishment in 1974, Maintracts Services has become a leading name in the heating industry.
Our team of expert heating engineers possesses extensive knowledge and expertise in dealing with ATG boilers, offering a comprehensive range of services including installation, maintenance, and repair. In today’s blog post, we will be delving into a topic that is crucial for every ATG boiler owner or technician to understand: common ATG boiler error codes.
These error codes can be perplexing, but worry not! We are here to provide you with valuable insights into what these error codes signify and how to effectively troubleshoot them.
Whether you’re a homeowner, a landlord, or a heating professional, join us as we unravel the mysteries of ATG boiler error codes and help you maintain optimal performance and reliability for your heating system.
ATAG boiler error codes
When an error occurs with your ATAG boiler, you will encounter an error symbol like the one depicted above. Typically, this symbol is accompanied by one of the codes listed in the tables below.
| Fault code | System behaviour |
| 10 | Outside sensor error |
| 20 | Flow sensor error |
| 40 | Return sensor error |
| 61 | Bus communication error |
| 78 | Water pressure out of range |
| 105 | Venting program active when power turned on / interrupted (runs for 7 mins) |
| 110 | Exceeded safety temperature |
| 111 | Exceeded maximum pressure |
| 119 | X2 link position 4 and 5 missing |
| 129 | Fan doesn’t start |
| 133 | No flame after 5 ignition attempts |
| 151 | Fan error or control unit defective (speed control is not achieved) |
| 154 | Return greater than flow – flow temperature increases too fast |
| 101 | Overheat error |
| 102 | Pressure sensor fault |
| 104 | Flow check failed |
| 108 | Pressure needs filling to < 0.5 bar |
| 1P4 | Pressure needs filling to 0.5 – 0.8 bar |
| 109 | Pressure > Pmax error |
| 110 | Send probe damaged |
| 112 | Return probe error – could be damanged |
| 114 | Outdoor sensor error – could be damaged |
| 141 | Central heating flow switch is open |
| 201 | Domestic hot water (DHW) probe damaged |
| 203 | Tank probe damaged |
| 303 | Printed circuit board (PCB) error |
| 304 | Too many resets have occured |
| 501 | No flame detected |
| 612 | Fan fault – fan isn’t starting up |
IC & IS Combi Boiler Error Codes
| Fault code | System behaviour |
| 50 | Domestic hot water (DHW) sensor error |
| 117 | Pressure greater than 3 bar or pump pressure increase is too high |
| 118 | Pressure less than 1 bar or pump pressure increase too low (no pump detection). |
Other Fault Codes
If you come across a spanner symbol, it could indicate one of two possibilities. Firstly, it may signify that your boiler is in service mode. Secondly, it could indicate a blockage issue.
In the case of a blockage, the code is typically temporary and will clear itself or will eventually lock the boiler after several repeated attempts if the error persists.
ATAG Error code 133
When encountering error code 133, it indicates that your boiler’s flame is failing to ignite after five attempts. This issue is commonly attributed to a frozen condensate drain pipe. Fortunately, a frozen condensate pipe is often a simple problem to resolve.
