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 has gained extensive knowledge and expertise in dealing with Heat Line boilers, offering a wide range of services including installation, maintenance, and repair. In today’s blog post, we will be diving into a topic that every Heat Line boiler owner or technician should be familiar with common Heat Line boiler error codes.
These error codes can be perplexing, but fear 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 demystify the world of Heat Line boiler error codes and help you ensure optimal performance and reliability for your heating system.
Heat Line Fault Codes
This table below will show the most common Heat Line faults based on an error code message:
| Fault code | Description | Solution |
| F00 | Flow heating temperature sensor fault | Verify the sensor’s connections. Verify the wiring harness. Verify the sensor |
| F01 | Return heating temperature sensor fault | Verify the sensor’s connections. Verify the wiring harness. Verify the sensor |
| F10 | Flow heating temperature sensor fault | Verify the sensor’s connections. Verify the wiring harness. Verify the sensor |
| F11 | Return heating temperature sensor fault | Verify the sensor’s connections. Verify the wiring harness. Verify the sensor |
| F20 | Overheating fault | Verify the operation of the pump. Verify the wiring harness. Verify that the fl ow and return heating isolation valves are open |
| F22 | Water pressure of the installation | Fill the installation. Purge the installation. Verify the pump connections. Verify the flow and return heating sensor connections. Verify that there are no leaks |
| F23 | Maximum temperature difference reached between return and flow heating | Verify the flow and return heating sensor connection. Verify the pump speed |
| F24 | Water circulation fault | Verify that the fl ow and return heating isolation valves are open |
| F26 | Fault in gas valve motor | Verify the gas valve connections. Verify the operation of the gas valve. Verify the operation of the condensate pump |
| F27 | Flame detection fault | Verify the flame detection electrode. Verify the main board. Verify the igniter unit |
| F28 | Ignition fault | Verify the return gas circuit (gas valve open). Verify the observe the flame picture and Verify the CO setting. Verify the igniter unit connections. Verify the state of the electrode |
| F32 | Incorrect air pressure | Verify the entire flue system. Verify the fan’s electrical connections |
| F49 | EBUS voltage fault | Verify that the eBus controls are fitted and wired correctly |
| F61-67 | Fault in the main board | Verify the main boards connections. Verify the main board. Verify the appliance DSN number is correct. Reset the appliance |
| F68 | Fluctuation of flame signal | Verify the return gas circuit (gas valve open). Verify the observe the flame picture and Verify the CO setting. Verify the igniter unit connections. Verify the state of the electrode . |
| F70 | User interface incompatible with the main board | Verify that the appliance DSN code on the screen matches the product code of the nameplate. Verify the boards reference |
| F71 | Flow heating temperature sensor fault | Verify the sensor connections. Make sure that the sensor is clipped to the tube |
| F72 | Permanent temperature difference between flow and return heating sensors | Verify temperature sensors connections. Replace faulty sensors |
| F73-74 | Heating circuit pressure sensor fault | Verify the sensor’s connections. Verify the sensor |
| F76 | Thermal fuse fault | Verify the fuses connections. Replace the heat exchanger |
| F77 | Fault in gas valve motor | Verify the gas valve connections. Verify the operation of the gas valve. Verify the operation of the condensate pump |
| F83 | No water in the installation: the temperature doesn’t increase when the burner is lit | Fill the installation. Purge the installation. Verify the pump connections. Verify the fl ow and return heating sensor connections. Verify that there are no leaks |
| F84 | Permanent temperature difference between flow and return heating sensors | Verify temperature sensors connections. Replace faulty sensors |
| F85 | Flow and return heating sensors fault | Verify temperature sensors connections |
| F86 | Underfloor heating contact fault | Verify the sensor connections. Verify that the sensor is connected to the main board and the shunt is removed |
| Err | User interface fault | Verify connection from user interface PCB to main PCB. Replace user interface |
This second table below will show central heating and hot water functionality fault finding:
| Fault | Action | Solution |
| No hot water | Is the central heating? Yes | Replace flow meter or/and D.H.W. sensor |
| No hot water | Is bar LED illuminating? Yes | Re-pressurize system |
| No central heating | Is there overheat LED illuminating? Yes | Replace overheat thermostats |
| No central heating | Is pump running? No | Check wiring / connections mains voltage |
| No hot water and no central heating | Open a hot tap to create a demand – is there a spark at the ignition electrode? Yes | Replace gas supply, pressure or gas valve |
| No hot water and no central heating | Open a hot tap to create a demand – is there a spark at the ignition electrode? No. Is fan running? Yes | Replace air pressure switch or overheat sensor |
| No hot water and no central heating | Are LEDs on? No | Replace user interface PCB |
| No hot water and no central heating | Is fan running? No | Replace low water pressure switch |
