Keep this blog handy for any help with deciphering your ATAG boiler error codes and for possible fixes. However, always remember, it is advisable to seek professional help when there’s a problem with your boiler. They are experienced and trained to understand and fix your boiler errors.
So, if you’d rather speak to one of our ATAG boiler experts directly, we totally understand and would love to guide you. Call 01442 832202 or email info@gastechheatingltd.co.uk now.
ATAG boiler error codes and fixes!
When your ATAG boiler encounters an error, it will flash an error sign as shown below. This sign or symbol will be accompanied by a code relevant to the issue.
In the following sections, we will explain the codes and possible causes and fixes related to the ATAG boiler issue.
Fault code 10
This refers to “Outside sensor error” which indicates a problem with the outside sensor in your heating or HVAC system. The outside sensor is typically responsible for measuring outdoor temperature or other environmental conditions.
Ensure the heating or HVAC system is turned off and follow safety guidelines. Locate the outside sensor, which is usually positioned outside your home or in a specific outdoor location. Check the wiring and connections related to the outside sensor.
Contact a qualified HVAC technician. They can diagnose the problem, repair or replace the sensor if necessary, and ensure accurate temperature measurements outdoors.
Fault code 20
The ATAG error is caused by “Flow sensor error”. It indicates a problem with the flow sensor in your heating system. The flow sensor is crucial for measuring the flow rate of a fluid, such as water or another heat transfer medium, within the system.
Locate the flow sensor within your system. It is typically positioned in the water or fluid flow path. Ensure all connections are secure and that there are no loose or disconnected wires. Inspect the flow path for any obstructions or blockages that might be hindering the flow sensor’s operation. Clear any debris or obstacles.
Fault code 40
“Return sensor error” or fault code 40 refers to a problem with the return sensor in your heating system. The return sensor typically measures the temperature of the fluid (such as water) returning from the system. It is typically positioned in the return flow path.
Inspect the return flow path for any obstructions or blockages that might be affecting the return sensor’s operation. Clear any debris or obstacles. If the return sensor is damaged, malfunctioning, or showing incorrect readings, it may need to be replaced with a new one. It is advisable to consult a local professional.
Fault code 61
This error is caused by a “Bus communication error”. A “bus” in this context typically refers to a communication pathway that allows different components or devices in the heating system to exchange information.
Determine which communication bus is experiencing the error. This could be a wired bus (such as Modbus or BACnet) or a wireless communication protocol. If it’s a wireless communication system, check for any sources of interference that might be affecting communication signals. Remove or mitigate sources of interference.
After addressing potential issues, reset the system according to the manufacturer’s instructions to see if the communication error clears. If the issue persists or if you’re uncertain about the cause, contact a qualified HVAC technician.
Fault code 78
The error code refers to the “Water pressure out of range” issue. It indicates that the water pressure in your heating or HVAC system is outside the acceptable range. Water pressure is a critical parameter that needs to be within specified limits for the system to operate efficiently and safely.
If your system has a pressure gauge, check its reading. The acceptable pressure range can vary depending on the specific system, so refer to the system’s documentation or user manual for the correct pressure range. Check the pressure relief valve to ensure it is functioning correctly. The relief valve releases excess pressure to prevent damage to the system.
Inspect the system for any visible leaks that might be causing a drop in water pressure. Call a registered engineer for help. They’re the right people to understand and fix these complex issues. At Gas Tech Heating, we offer emergency boiler repair services for homes and businesses. Feel free to reach out!
Fault code 105
This ATAG error code refers to the cause “Venting program active when power turned on / interrupted (runs for 7 mins)” and suggests that your heating or HVAC system is programmed to run a venting cycle for a duration of 7 minutes when power is turned on or interrupted. Venting is a process in some systems where combustion byproducts or air are expelled to ensure proper combustion and safety.
Refer to your system’s documentation or user manual to understand the specific details of the venting program. Manufacturers provide information on the purpose and duration of such cycles. If the venting program is triggered by power interruptions, consider using a power backup solution (like an uninterruptible power supply – UPS) to maintain power during brief interruptions and prevent unnecessary venting cycles.
Fault code 110
The cause of this error is the “Exceeded safety temperature”. It indicates that the temperature in your HVAC system has surpassed a predefined safety limit. This safety feature is designed to prevent overheating and potential damage to the system.
Determine what might be causing the temperature to exceed the safety limit. Potential causes include issues with the thermostat, malfunctioning sensors, or restricted airflow.
Inspect the system for any obstructions or issues that might be restricting airflow. Blocked vents or a clogged air filter can lead to overheating. If your system has temperature sensors, check for proper calibration. Follow the manufacturer’s instructions to calibrate sensors accurately.
Note: This error code also often refers to another cause, namely “Send probe is damaged” in your heating or HVAC system. It refers to an issue with the sensor responsible for sending information or feedback within the system. Identify the location of the damaged send probe in your system. It may be part of a sensor network or a specific component. Visually inspect the send probe for any visible signs of physical damage. This could include broken wires, loose connections, or other issues.
Fault code 111
This boiler issue is caused by “Exceeded maximum pressure”. It indicates that the pressure in your heating system has gone beyond the specified maximum limit. This is a safety feature to prevent potential damage to the system due to excessive pressure.
Inspect the pressure relief valve to ensure it is functioning correctly. The relief valve releases excess pressure to prevent damage to the system. If your system allows for pressure adjustment, follow the manufacturer’s instructions to adjust the pressure to within the acceptable range. Regular boiler servicing by a professional and experienced team can help avoid these unexpected issues.
Fault code 119
The possible cause of this error is “X2 link position 4 and 5 missing”. It suggests that there is an issue with the X2 link, specifically positions 4 and 5. X2 links are typically used in electronic systems to configure or connect different components.
Identify the location of the X2 link in your system. It might be on a circuit board or a specific module. Verify whether the X2 link is correctly positioned. If positions 4 and 5 are missing, it indicates that the link might be incomplete or incorrectly configured. If the X2 link is removable, try repositioning it according to the manufacturer’s specifications. If it’s damaged or missing, you may need to replace it.
Fault code 129
This code refers to the “Fan doesn’t start” problem in your boiler system. If the fan in your heating or HVAC system doesn’t start, it could be due to various reasons. Verify that there is power reaching the unit. Ensure that circuit breakers are not tripped, and fuses are intact. If there’s a power issue, it may prevent the fan from starting.
Check the thermostat settings. Ensure that the thermostat is set to a temperature that should trigger the fan to start. If the thermostat is battery-powered, replace the batteries. If your system has a manual fan switch on the thermostat, make sure it is set to the “On” position.
The fan motor might be equipped with a capacitor. A faulty capacitor can cause the fan not to start. A qualified technician can test and replace the capacitor if necessary.
Fault code 133
“No flame after 5 ignition attempts” or fault code 133 suggests a problem with the heating system in which it is unable to establish a flame after multiple ignition attempts.
Verify that there is a steady and sufficient supply of gas to the system. Ensure that the gas valve is open. Check the ignition system components, including the igniter and flame sensor. If your system has a pilot light, ensure that it is lit. If it’s not, follow the manufacturer’s instructions for relighting the pilot.
Inspect the burner assembly for any visible damage or blockages. Ensure there are no obstructions in the air intake or exhaust vents. Restricted airflow can affect combustion. Some systems have safety switches that can prevent ignition if certain conditions are not met. Ensure that all safety switches are in their correct positions. Call a Gas Safe registered engineer immediately for help with the situation.
Fault code 151
This error code refers to the “Fan error or control unit defective (speed control is not achieved)” issue in your ATAG boiler. It suggests that there is an issue either with the fan itself or with the control unit responsible for regulating the fan speed.
Verify that there is power reaching the fan and control unit. Ensure that circuit breakers are not tripped, and fuses are intact. Examine the wiring and connections related to the fan and control unit. Check the fan motor for any visible damage or signs of malfunction. Ensure that the blades are not obstructed and can spin freely. If the fan or control unit is found to be defective, replacement might be necessary. Follow the manufacturer’s guidelines for replacement parts.
Fault code 154
“Return greater than flow – flow temperature increases too fast” or error code 154 indicates an abnormal condition where the temperature of the return fluid in your heating or HVAC system is higher than the flow temperature, and the flow temperature is increasing too rapidly. This situation can be a sign of improper system operation and may need attention.
Inspect the temperature sensors in the system, both for the flow and return sides. Ensure they are correctly positioned, securely connected, and functioning properly. Airlocks in the system can disrupt the proper flow of water. Bleed the radiators and check for any trapped air in the system.
Inspect the pipes and radiators for any blockages. Blocked components can cause irregular flow patterns and temperature differentials. If the issue persists or if you are uncertain about performing these checks, it’s advisable to contact a qualified boiler technician.
Fault code 101
This particular error code is caused by the “Overheat error” problem in your boiler system. This means that your heating or HVAC system has detected an overheat condition, where the temperature has exceeded safe limits. This could be caused by various issues, and it’s important to address it promptly.
Dirty or clogged air filters can impede airflow and contribute to overheating. Check and replace air filters if necessary. Inspect radiators or heat exchangers for blockages or buildup. Clear any debris that might be hindering heat dissipation. Look for any water or fluid leaks in the system. Low fluid levels can cause the system to overheat.
Fault code 102
This code is displayed when there’s a “Pressure sensor fault” in your boiler. It indicates an issue with the pressure sensor that is responsible for monitoring the pressure within the system.
Turn off the heating or HVAC system and follow safety guidelines before attempting any checks. If your system has a pressure gauge, check the readings. Abnormal pressure readings could indicate a faulty pressure sensor. Some systems allow for pressure sensor calibration. Follow the manufacturer’s instructions to calibrate the pressure sensor accurately. If the pressure sensor is found to be faulty or damaged, it may need to be replaced. Call a boiler repair engineer for help.
Fault code 104
The message corresponding to this ATAG boiler error code is “Flow check failed”. It suggests that there’s an issue with the flow of fluid (such as water or another heat transfer medium) within the system.
Inspect the pipes, valves, and components for any blockages that might be hindering the flow of fluid.
Clear any debris or obstructions. Check that the circulation pump is operating correctly. If your system has valves, ensure that they are open and allowing proper fluid flow. If there are airlocks in the system, bleed the radiators or use air vents to release trapped air. Airlocks can disrupt the flow of fluid.
Fault code 108
“Pressure needs filling to < 0.5 bar” or error code 108 suggests that the system’s pressure has dropped below the recommended level. Identify the pressure gauge on your system. This gauge typically displays the current pressure level.
Inspect the system for any visible leaks, especially around pipes, connections, valves, and radiators. If you find any leaks, repair or replace the damaged components. If the pressure is below the recommended level, you’ll need to refill the system. Most systems allow you to do this using a filling loop or a filling valve. Follow the manufacturer’s instructions for your specific system to refill the water or heat transfer fluid.
Fault code 1P4
This error code is caused by the “Pressure needs filling to 0.5 – 0.8 bar” problem in your boiler.
If your heating or HVAC system indicates that the pressure needs filling to 0.5 – 0.8 bar, it means that the system’s pressure has dropped below the optimal range, and it needs to be increased.
Identify the pressure gauge on your system. This gauge typically displays the current pressure level. If the pressure is below the recommended range (0.5 – 0.8 bar), you’ll need to refill the system. Most systems allow you to do this using a filling loop or a filling valve. Follow the manufacturer’s instructions for your specific system to refill the water or heat transfer fluid.
Once you’ve refilled the system, monitor the pressure on the gauge. Adjust the pressure using the filling loop or valve to bring it within the recommended range (0.5 – 0.8 bar).
Fault code 109
“Pressure > Pmax error” or ATAG error code 109 indicates that the pressure in your heating or HVAC system has exceeded the maximum allowable limit (Pmax). This can be a critical issue that needs immediate attention to prevent damage to the system.
Check the pressure relief valve. This valve is designed to release excess pressure to prevent damage. If the valve is malfunctioning or if there is water discharging from it, it may need to be replaced. Inspect the pipes, valves, and components for any blockages that might be causing the pressure to spike. Clear any debris or obstructions.
Given the critical nature of the error, it’s advisable to contact a qualified engineer immediately. They can conduct a thorough diagnosis, identify the root cause, and perform any necessary repairs or adjustments.
Fault code 112
This error code is displayed when there’s the “Return probe error – could be damaged” problem in your heating system. It indicates a potential issue with the sensor responsible for measuring the return temperature in the system.
Identify the location of the return probe in your system. Visually inspect the return probe for any visible signs of physical damage. Check for broken wires, loose connections, or other issues. If the return probe is found to be damaged and cannot be repaired, it may need to be replaced.
If the system allows for calibration or configuration of sensors, follow the manufacturer’s instructions to ensure proper settings for the new or repaired return probe.
Fault code 114
“Outdoor sensor error – could be damaged” is the probable cause behind this error code. It indicates a potential issue with the outdoor temperature sensor. Identify the location of the outdoor temperature sensor. It’s usually installed outside the building to measure the ambient temperature.
Visually inspect the outdoor sensor for any visible signs of physical damage. Examine the wiring and connections related to the outdoor sensor. Ensure all connections are secure and that there are no loose or disconnected wires. Ensure that there are no obstructions or environmental factors affecting the outdoor sensor. Clear any debris or obstructions that might be impacting its accuracy.
Fault code 141
Fault code 141 refers to the “Central heating flow switch is open” issue in your boiler system. It indicates that there is an issue with the flow switch in the central heating system.
Identify the location of the central heating flow switch in your system. It is typically installed in the central heating circuit. Examine the wiring and connections related to the central heating flow switch.
If possible, perform a manual test of the central heating flow switch. Some systems allow you to simulate the flow to check if the switch operates correctly. If the flow switch is found to be faulty and cannot be repaired, it may need to be replaced. A professional will be able to help promptly.
Fault code 201
“Domestic hot water (DHW) probe damaged” is the cause that gives rise to this error code in your ATAG boiler. It suggests an issue with the sensor responsible for measuring the temperature of the domestic hot water.
Identify the location of the DHW probe in your system. It is typically connected to the hot water storage or heating unit. Visually inspect the DHW probe for any visible signs of physical damage. Inspect the hot water storage or heating unit for any water leaks. Leaks can affect the proper functioning of the DHW probe.
Fault code 203
The error code 203 refers to the error message “Tank probe damaged”. It suggests an issue with the sensor responsible for measuring parameters related to the tank (such as temperature or level).
Identify the location of the tank probe in your system. It may be part of a sensor network or connected to a specific component. Ensure all connections are secure, and there are no loose or disconnected wires. If the tank probe is found to be damaged and cannot be repaired, it may need to be replaced.
If the probe measures tank parameters such as temperature or level, inspect the tank for any issues that might affect the readings, such as leaks or malfunctions.
Fault code 303
“Printed circuit board (PCB) error” causes this fault code to flash in your boiler. It indicates a problem with the electronic control board responsible for managing the system’s functions.
Sometimes, a PCB error can be a temporary glitch. Turn off the system, wait for a few minutes, and then turn it back on to see if the error clears. Some systems have a reset button or a specific procedure for resetting the PCB. Follow the manufacturer’s instructions to perform a system reset.
Visually inspect the PCB for any signs of physical damage, such as burned areas, damaged components, or loose connections. The PCB error could be a result of a malfunctioning component on the board. A qualified technician can use diagnostic tools to identify and replace any faulty components.
Fault code 304
When you see code 304 flashing in your boiler model, know that it is most likely due to the “Too many resets have occurred” issue in its system. It suggests that the system has undergone multiple reset attempts within a short period. This could be due to an underlying issue that needs attention.
Examine the system logs or error messages to identify the root cause of the repeated resets. This could be related to a malfunctioning component, a sensor issue, or other system faults. Visually inspect critical components, such as the control board, sensors, and wiring, for any signs of physical damage, loose connections, or other issues.
If any changes or modifications have been made to the system recently, review them. Changes in settings, components, or installations could be contributing to the issue.
Fault code 501
This error code refers to the problem “No flame detected” in your heating system. It suggests that the system is not detecting the presence of a flame when it should be active.
Ensure that the gas supply to the boiler is active and that there are no issues with the gas line. If there is a gas supply issue, it should be addressed by a qualified and Gas Safe engineer.
Check the ignition system, including the pilot light or electronic ignition, to ensure that it is functioning correctly. Ignition problems can lead to a failure to detect a flame. The flame sensor is a safety feature that detects the presence of a flame. If it’s dirty or malfunctioning, it may not detect the flame. Clean or replace the flame sensor as needed.
Fault code 612
“Fan fault – fan isn’t starting up” is the possible issue that’s causing this error code in your ATAG boiler. It suggests a problem with the fan component. Check the fan blades for any obstructions or debris that might be preventing it from starting. Clear any debris or blockages.
Inspect the wiring connected to the fan for any signs of damage, loose connections, or disconnections. Some systems use capacitors to help start the fan motor. If applicable, check the capacitor for proper functioning. If the fan motor has bearings, check them for wear or damage. Lubricate or replace the bearings as needed.
IC & IS combi boiler error codes
Fault code 50
This error code is likely caused by the “Domestic hot water (DHW) sensor error” issue in your combi boiler. It indicates a problem with the sensor responsible for measuring the temperature of the domestic hot water.
Identify the location of the DHW sensor in your system. It is typically connected to the hot water storage or heating unit. Inspect the DHW sensor for any visible signs of physical damage. Check for broken wires, loose connections, or other issues.
If the DHW sensor is found to be damaged and cannot be repaired, it may need to be replaced. Follow the manufacturer’s guidelines for replacing parts.
Finally, if you are uncertain about the cause of the issue, how to replace the sensor, or if the system requires professional recalibration, it’s advisable to contact an experienced plumbing company in your area.
Fault code 117
This means your boiler has encountered the “Pressure greater than 3 bar or pump pressure increase is too high” issue in its system. It suggests that the system pressure has exceeded the recommended limit.
Identify the pressure gauge on your system and check the current pressure reading. If it exceeds 3 bar, it needs attention. Inspect the pressure relief valve. This valve is designed to release excess pressure to prevent damage. If the valve is discharging water, it may indicate a pressure issue.
The expansion vessel absorbs excess water in the system, helping to regulate pressure. Check the expansion vessel for proper functioning and pressure. If your system allows for pressure adjustment, follow the manufacturer’s instructions to reduce the pressure to within the recommended range.
Fault code 118
This code refers to the “Pressure less than 1 bar or pump pressure increase too low (no pump detection)” issue in your combi boiler. It indicates that the system pressure is below the recommended level or that the pump is not operating as expected.
Identify the pressure gauge on your system and check the current pressure reading. If it is below 1 bar, it needs attention. Inspect the system for any visible leaks, especially around pipes, connections, valves, and radiators. Leaks can contribute to pressure issues.
If there are airlocks in the system, bleeding radiators can help release trapped air, which may be contributing to low pressure. If your system has a pump, check its operation. A malfunctioning pump or a lack of pump detection can contribute to pressure problems.
Spanner symbol issue in ATAG boilers
A spanner symbol can be caused by two possible things: it could either mean that your boiler is in service mode, or it could be blocking. If it is blocking, the code is temporary. It will clear itself out or lock the boiler after some attempts if the error keeps on occurring.
Conclusion
A sudden occurrence of an error code in your boiler can be a painful situation, and we understand that. The reason why with this article, we aim to make it as stress-free for you as possible. In addition to the ATAG boiler, we have also written and explained the error codes of some of the other popular boiler manufacturers. Check out Ariston boiler error codes and Baxi boiler error codes on our blog. We hope these blogs give you the insights you require to strategically and efficiently handle these situations. Please ensure that you seek professional help for the safety and efficacy of your boilers.
