Staying warm and comfortable throughout the year is a crucial aspect of living in Hemel Hempstead and its surrounding areas. And for that to happen, businesses and homeowners rely on the popular Ariston boilers which are a sustainable choice in the UK. However, when your boiler goes out of order, it can be quite a problem; especially so in the winter months. You often scramble with the error codes, not knowing what to do about them. In this blog, we’ll address this issue by delving into common Ariston boiler error codes, their causes, and practical solutions.
Ariston central heating circuit error codes
1. Fault code 101
This applies to all boiler models of Ariston, and it indicates an overheating issue. Possible fixes can include switching off the boiler, checking radiators and pipes, resetting the boiler with the reset button, checking for adequate airflow, etc. However, it is advisable to seek professional help. At Gas Tech Heating, we have 24/7 service available, so you can solve your Ariston boiler issues at any time.
2. Fault code 102
This error code applies to E-Combi Evo, E-System Evo, and Clas He Evo (Combi and system) models. This indicates that there is a pressure sensor error. Fixing this error requires professional and technical knowledge. You need to ensure safety and start with checking the pressure gauge. You may need to repressurise the system or release excess pressure.
3. Fault code 103-107 and 1p1-1p4
Codes 103 to 107 apply to all Ariston boiler models and indicate insufficient circulation issues. Error codes 1p1 to 1p3 also indicate the same issue and they apply to all models. Error code 1p4 is applicable for only Clas Net one Combi, Clas one Combi, and Clas System one models, and it indicates the same insufficient circulation issue. You will need to check radiators and pipes and bleed radiators if needed. Professional assistance is advisable for efficiency and safety.
4. Fault code 108
This code is applicable for all Ariston Combi boiler models and indicates an insufficient water (request filling) issue. It is quite apparent what the possible fix could be for this issue; your boiler needs more water to operate correctly.
5. Fault code 109
This error code applies to Clas net one /Clas one Combi and Clas system one models. It indicates that the pressure in your boiler’s heating system has exceeded the recommended limit of 3 bar. You need to Slowly open the pressure relief valve to release excess pressure. Be cautious, as hot water or steam may be released. Taking the help of a professional is advisable.
6. Fault code 110 and 112
Code 110 applies to all boiler models and indicates the “Central heating flow temperature probe circuit open / short circuit” issue. Which means that there’s a problem with the flow temperature probe in your central heating system.
Code 112, too, applies to all models and indicates the “Central heating return temperature probe circuit open / short circuit” issue. This means that the return temperature probe circuit may be faulty in your boiler.
For both issues, you may need to check and repair wiring with the help of a professional engineer.
7. Fault code 114
This error code is applicable for all Ariston boilers and indicates an “External sensor circuit open / short circuit” issue. You will have to locate and inspect the sensor. This may be caused by loose or disconnected wires in your boiler.
8. Fault code 116
This applies to all Combi and System boilers and the issue is “Floor thermostat contact open”. This message means that the circuit is open, and the thermostat is not making proper contact. You will have to check the thermostat wiring to fix the problem. It is advisable to contact local boiler engineers for help.
9. Fault code 118
This code may be shown in all boiler models and indicates a “Heating delivery probe problem” issue. You will need to locate the delivery probe and inspect it for possible damages in wiring and connections.
D.H.W or hot water circuit error codes
10. Fault code 202, 204, 205
Codes 202 and 204 are only applicable for Ariston Clas HE evo, Clas HE evo system, E-combi evo, and E-system evo models. They indicate “2 bottom storage temperature probe open/short circuit” and “Solar collector temperature probe open/short circuit” issues respectively.
The first issue for 202 means there’s a problem with the temperature probe in the bottom storage of your heating system. You will have to get professional help in locating the probes and checking for possible wiring issues.
The second problem for 204 means there’s a problem with the temperature probe in your solar collector system. This probe is used to measure the temperature of the solar collector. You may reset the solar collector system but it’s advisable to ask a professional to check the issue.
Code 205 is applicable for E-combi one, E-System one, Clas Net one Combi, and Clas one Combi models. It indicates a “Domestic hot water in probe open circuit” issue in your boiler. You will need to locate the temperature probe and check it for wiring and connection issues.
11. Fault code 207 and 208
Both these codes apply to Ariston’s Clas HE evo, Clas HE evo system, E-combi evo, and E-system evo models. 207 indicates a “Solar collector overheating” issue which means the solar collector system is too hot. You will need to check for obstructions that might be blocking airflow in it. You may also need to check fluid levels and shade the collector if needed.
Code 208 indicates the “Collector frost protection temperature” issue which means the problem is related to the frost protection feature in a solar collector system. This feature is designed to prevent damage to the system during freezing conditions. Ensure that the collector’s frost protection system is enabled. You can also examine the solar collector and its components for any visible signs of frost or ice buildup.
Internal printed circuit board (PCB) error codes
12. Fault code 301 and 302
Both these Ariston error codes are applicable for all boiler models. 301 indicates “EEPROM error” which means there’s a problem with the Electrically Erasable Programmable Read-Only Memory in the system. A simple reset of the boiler may solve this issue. These issues often arise from a lack of boiler servicing.
Code 302 indicates a “Communication error” issue which means there’s a problem with the communication between various components or systems in a device or heating system. You will need to check the communication cables. There may also be a need to update the software.
13. Fault code 303, 305, 306, 307
These codes apply to all Ariston boiler models and indicate the same common “Main printed circuit board (PCB) error” issues. You will need to check the main circuit board for possible loose connections or burnt components. Ask a professional boiler engineer to take a look at it.
14. Fault code 304
This error code may be seen in all boiler models, and it indicates a “Too many resets (> 5) in 15 minutes” issue. This may happen when there’s a recurring problem with the system that has caused it to reset multiple times within a short period. You will need to check the main power supply, any indication of overheating in the system, and other components of the system. It is advisable that you seek expert help to ensure safety.
15. Fault code 3P9
This Ariston error code is applicable for E-combi one, E-System one, Clas Net one Combi, Clas one Combi, and Clas System one models. This suggests that it’s time to arrange maintenance or servicing for a device or system. You will need to contact the service provider.
External printed circuit board (PCB) error codes
16. Fault code 407
This error code applies to Clas HE evo, Clas HE evo system, E-combi evo, and E-system evo boiler models. This code indicates the “7 Room sensor circuit open/short circuit” issue. It means there’s a problem with the room sensor circuit in your heating system. To start with, you can turn off the heating system and locate the room sensor to check wiring and connections.
17. Fault code 411, 412, and 414
These three error codes apply to Ariston’s Clas Net One, Clas One, E-Combi and E-System models. They indicate a “Room sensor circuit open or short circuit” issue for zone 1, zone 2, and zone 3 respectively.
It suggests a problem with the room sensor circuit in your heating or HVAC system. This issue can occur due to a break or short in the circuit, which affects the sensor’s ability to measure temperature accurately. Check the wiring and connections and short circuits. If you have the necessary tools and knowledge, you can also use a multimeter to measure the resistance of the room sensor circuit. But we’d suggest that you only rely on professional engineers for this job.
Ignition and detection error codes
18. Fault code 501, 502, 504, and 5P3 (Flame-related issues)
These Ariston fault codes are applicable to all models. 501 indicates a “No flame detected” issue which means that your heating system has failed to detect a flame when it’s expected to be present. This can be a safety feature to prevent the system from operating without proper ignition. Verify that the ignition sequence for your heating system is working correctly. This includes the fuel supply, spark or pilot light ignition, and flame detection sensors.
Code 502 refers to the “Flame detected with gas valve closed” issue. This means a serious safety issue where the heating system’s flame sensor is detecting a flame even when the gas valve, responsible for controlling the gas supply, is closed. This is a potentially dangerous situation and must be addressed promptly. Contact Gas Tech Heating for emergency service from expert Gas Safe registered engineers.
Code 504 refers to an issue with “Flame lift” which means the flame in a combustion system has become unstable and lifted away from its intended location, potentially causing issues with combustion and safety. Immediately turn off the heating or combustion system to prevent potential hazards and contact professionals.
Code 5P3 indicates that the flame in your heating system has been intentionally shut off, either due to a safety feature or a detected issue. Examine the heating system for any visible problems or issues that might have caused the flame to be cut off. This could include issues with the fuel supply, ignition, or other components.
19. Fault code 5P1 and 5P2
These codes apply to all boiler models and indicate “1st ignition failed” and “2nd ignition failed” issues respectively. “1st ignition failed” typically indicates that the initial attempt to ignite the heating system has not been successful. Verify that there is an adequate supply of fuel, such as gas or oil, to the heating system.
The message “2nd ignition failed” suggests that the heating system’s second attempt at ignition has not been successful. This issue can occur due to various reasons, including fuel supply problems or ignition system malfunctions. Examine the ignition components, such as the pilot light or spark igniter, for any damage or malfunction. Clean any dirty or clogged components as needed.
Air inlet / flue gas outlet error codes
20. Fault code 604, 610, and 612
Code 604 is common in CLAS HE R, E-Combi Evo, E-System EVO, Clas HE evo Combi, and Clas HE evo System models of Ariston boilers. This indicates an “Insufficient fan speed” issue. The fan in your heating or ventilation system is not operating at the required speed. This can affect the system’s efficiency and performance. Inspect the fan and its surroundings for any obstructions that might be limiting airflow. Remove any debris or objects that could be impeding the fan’s operation. Regular servicing will help prevent such issues.
Code 610 is common for all models, and it indicates that the thermal fuse in your heating system is open, which means it has blown or tripped. This is typically a safety feature designed to protect the system from overheating.
Error code 612 may occur in Clas HE Evo Combi, Clas He Evo System, E-Combi Evo, E-system Evo, Clas net one combi, Clas one combi, Clas system one boiler models. It shows that the fan speed has incorrect measurements. Inspect the fan. If the fan is not running or is running at an unusual speed, this could be the source of the measurement error. Check the wiring and connections related to the fan speed sensor. Loose or disconnected wires can lead to incorrect measurements.
Multi-zone heating error codes
21. Fault code 711 (Zone 1 issue)
This Ariston error code is specifically applicable for Clas Net One, Clas One, E-Combi and E-System models. They indicate a “Return sensor defective (zone 1)” issue in your boiler. This sensor is responsible for measuring various parameters such as temperature or pressure in the return flow from the zone. Turn off the system immediately and locate the return sensor to check the wiring and connections.
22. Fault code 701, 702, 706, 712, and 722 (Zone 2 issues)
Ariston error code 701 applies to E-Combi Evo, E-System EVO, Clas HE evo combi, and Clas HE evo system models. It indicates a problem with the outgoing sensor in the second zone of your heating or HVAC system. Turn off the heating system and locate the outgoing sensor for the second zone. It may be located in a duct, pipe, or specific area within the zone. Examine the sensor for any visible damage or loose connections.
** Fault code 701 can mean “Send sensor defective (Zone 1)” issue for Clas Net One, Clas One, E-Combi and E-System models. The send sensor is responsible for measuring various parameters such as temperature or pressure. You should check the sensor for damage or connection issues.
Code 702 is applicable for E-Combi Evo, E-System EVO, Clas HE evo Combi, and Clas HE evo System models. It gives an error message “Zone 2 return sensor defective” which indicates a problem with the return sensor in the second zone of your heating or HVAC system. Check the wiring and connections related to the sensor. If the sensor allows for calibration, follow the manufacturer’s instructions to calibrate it properly.
Code 706 error may arise in E-Combi Evo, E-System EVO, Clas HE evo combi, and Clas HE evo system models. This indicates that the second zone in your heating or HVAC system is experiencing higher temperatures than desired or recommended. Check the thermostat, inspect vents and ducts. Ensure that windows and doors in the second zone are closed.
Code 712 is the equivalent of code 702 for Clas Net One, Clas One, E-Combi and E-System models. Similarly, code 722 is an indication of the same issue as that of code 706, but for Clas Net One, Clas One, E-Combi and E-System models.
23. Fault code 703, 704, 707, 713, and 723 (Zone 3 issues)
Code 703 applies to E-Combi Evo, E-System EVO, Clas HE evo combi, and Clas HE evo system Ariston models. It indicates a “Zone 3 outgoing sensor defective” issue in your boiler. The outgoing sensor in the second zone of your heating or HVAC system must be faulty. You can inspect the sensor on your own. However, it is advisable to seek professional help.
Code 704 is applicable for E-Combi Evo, E-System EVO, Clas HE evo Combi, and Clas HE evo System boiler models. It refers to the “Zone 3 return sensor defective” issue in the system. To start with, you can check the wiring and connections in the sensor. However, we suggest that you take expert help to ensure the safety and efficiency of the system.
Error code 707 can be found in E-Combi Evo, E-System EVO, Clas HE evo Combi, and Clas HE evo System models. It indicates overheating in the zone 3 of your heating system. Inspect the vents and ducts for possible obstructions and call an engineer for further help.
Code 713 is the equivalent of code 704 for Clas Net One, Clas One, E-Combi and E-System models. Similarly, code 723 is the equivalent of code 707 for this same set of boiler models.
When you encounter a sudden error code or message in your boiler system, it’s natural to panic and look for explanations and solutions. However, we always advise people to not rush into a DIY solution right away. These issues may be hazardous and always require special attention and thorough checking.
At Gas Tech Heating, we have been serving homeowners and businesses for over 40 years to help with their boiler, heating, and plumbing issues in Hemel Hempstead. We hope that this detailed article has given you helpful insights into possible issues with your boiler system. Contact our expert and registered engineers today for help with any boiler-related problems. We offer 24/7 service.