Available 24/7, 365 days 
Call us on:
0203 504 4000
In the world of boilers, Glow-worm is a well-known and trusted brand. However, like any other appliance, Glow-worm boilers can experience faults from time to time. These faults are typically indicated by error codes that appear on the boiler’s display panel. Understanding these fault codes is crucial for homeowners, as it can help them identify and address any problems with their boiler system.
| Boiler Model | Fault Codes | Cause of Problem |
| Betacom | Red LED On | Lockout – low water pressure (increase pressure to 1.5bar) and reset boiler |
| Betacom | Red LED flashing | Overheat – check both overheat stats |
| Betacom | Yellow LED flashing | Turn domestic hot water (DHW) control knob into temperature range and turn central heating (CH) temperature control knob into power (reset position) |
| Betacom | Yellow LED on | Flame present on the burner |
| Betacom | Green LED on | Green LED on |
| Betacom | Green LED off | No power to boiler – Check for 230volts into the appliance, check the fuse on printed circuit board (PCB) |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F00 / F10 / F71 | Flow heating temperature sensor fault |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F01 / F11 | Return heating temperature sensor fault |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F20 | Overheating fault |
| Betacom4 / Ultracom3 cxi / sxi / hxi / 35 / Flexicom cx / hx / sx | F9 / F22 | Low water pressure (or ignition temperature rise too slow) |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F26 / F77 | Fault in gas valve |
| Betacom4 / Ultracom3 cxi / sxi / 35 / CI / hxi / Xtramax HE | F27 / F16 | Flame detection fault |
| All Boilers | F28 / F1 / F4 | Ignition fault (flame detection) |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F29 | Loss of flame during operation |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F32 | Incorrect air pressure |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F49 | EBUS voltage fault |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F61 / F62 / F63 / F64 / F65 / F67 | Fault in the main board |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F68 | Fluctuation of flame signal |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F70 | User interface incompatible with the main board |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F72 / F84 | Permanent temperature difference between flow and return heating sensors |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F73 / F74 | Heating circuit pressure sensor fault |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F76 | Thermal fuse fault |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F83 | Thermal fuse fault |
| Betacom4 / Ultracom3 cxi / sxi / 35 | F85 | Flow and Return heating sensor fault |
| Betacom4/ Ultracom3 cxi / sxi / 35 | F86 | Underfloor heating contact fault |
| All Boilers | ERR / F12 / F18 | User interface fault |
| Betacom c | Temperature 30 flashing | Fault on central heating (CH) thermistor |
| Betacom c | Temperature 40 flashing | Fault on DHW thermistor |
| Betacom c | Temperature 50 flashing | Fault on outside sensor |
| Betacom c | Temperature 60 flashing | Low system pressure |
| Betacom c | Temperature 70 flashing | Fault on APS |
| Betacom c | Temperature 80 flashing | Overheat open circuit |
| Betacom c | Temperature 90 flashing | Flame or gas failure |
| Compact e / s | No DHW | Check dhw microswitch / Check external controls, Please test for 230V on switch live contact |
| Compact e / s | No C/H | Check dhw microswitch if dhw demand led is lit / Check external controls, Please test for 230V on switch live contact |
| Compact e / s | No C/H but boiler is firing | Check divertor motor and cartridge / Check external controls, Please test for 230V on switch live contact |
| Compact e / s | Boiler locks out within 10 seconds | Check pump proving switch, air pressure switch and overheat state / Check pump proving switch, air pressure switch and overheat stat |
| Compact e / s | Poor burner pressure | Check burner pressure/ignition adjustment pots on PCB |
| Ci Range (plus) / Si range | F2 | Fan/APS |
| All Boilers | F5 | Overheat Fault |
| All Boilers | F6 | Central heating flow thermistor |
| All Boilers | F7 | Domestic hot water thermistor |
| All Boilers | F8 | Tank thermistor fault |
| sxi / si / ci (plus) range / Xtramax HE | F9 | Water pressure sensor fault (please contact GW technical department for further information) |
| All boilers | F10 | Central return flow thermistor |
| All boilers | F11 | Main board connection fault |
| Ci (plus) / cxi / hxi / si / sxi range | F12 | Connection fault between main printed circuit board (PCB) and display PCB |
| Ci (plus) / cxi / hxi / si / sxi range | F13 | Main pcb connection fault |
| Ci (plus) / cxi / hxi / si / sxi range | F14 | Central heating flow temperature > 95 degrees |
| Ci (plus) / cxi / si / sxi range | F15 | Gas valve stepper motor fault |
| Ci (plus) / cxi / hxi / si / sxi range / Xtramax HE | F17 | Power supply is less than 170v |
| Ci (plus) / cxi / hxi / si / sxi range / Xtramax HE | F19 | Central heating thermistor unplugged |
| Ci (plus) / cxi / hxi / si / sxi range / Xtramax HE | F20 | Software incompatibility |
| cxi / hxi / sxi range / Flexicom cx | F24 | Central heating return temperature > 90 degrees |
| cxi / hxi / sxi / Xtrafast 96/120 / Xtrafast 96/120E1 | F25 / F26 / F11 | Poor circulation |
| ci range | F3 | Air fault |
| cxi / sxi / hxi range/ Xtramax HE | F2 / F3 | Fan |
| cxi / sxi range / Flexicom cx / hx / sx / hxi / Ultracom cxi / cx / hxi / sxi / Ultrapower sxi | F3 | Fan unable to reach ignition speed |
| Flexicom cx / hx / sx / hxi / Ultracom cxi / cx / hxi / sxi | F9 | Water pressure sensor fault, blocked flow filter or pump fault |
| Flexicom cx / hx / sx | F11 | Flow and or return thermistor fault |
| Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HE | F13 | PCB memory or sensing fault |
| Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HE | F14 | Gas valve control defective |
| Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi / Xtramax HE | F15 | E-bus voltage failure |
| All boilers | F25 / F23 | Circulation fault |
| Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi | F43 | Generic error |
| Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi | F70 | Software incompatible |
| Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi | F73 | Unable to see pump activate |
| Flexicom cx / hx / sx / Ultracom cxi / cx / hxi / sxi | F77 | Condensate pump error (optional) |
| hxi range | F9 | Earlier models only (please contact GW technical department for further information) |
| Ultracom? 35 Store | F02 / F12 | Hot water temperature sensor fault |
| Ultracom? 35 Store | F03 / F13 / F79 | Storage tank temperature sensor fault |
| Ultracom? 35 Store | F81 | Overheating of hot water circuit |
| All Ultracom | No display or Er | loose connection X51 |
| Xtramax HE Range | F24 | Cental heating return temperature > 90 degrees |
| Xtramax HE Range | F25 | Maximum temperature rise slope |
| Xtramax HE Range | F26 | Maximum delta temperature |
| Xtrafast 96/120 Range | F00 | No-fault |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F00 | No-fault |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F02 | Airflow fault |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F05 | Overheating |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F06 | Central heating thermistor/wiring fault |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F08 | Storage vessel thermistor/wiring fault |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F09 | System pressure sensor fault |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F10 | Fan fault |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F13 | Main printed circuit board (PCB) fault |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F14 | Central heating flow temperature > 97 degrees |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F15 | Gas mechanism fault |
| Xtrafast 96/120 Range / Xtrafast 96/120E1 Range | F20 | Communication fault |
*table credit: WarmZilla
When it comes to Glow worm boiler fault codes, it’s important to start with the basics. So, what exactly are these fault codes, and why are they significant?
Let’s delve deeper into the world of Glow worm boiler fault codes and explore the fascinating details behind their existence.
In simple terms, fault codes are alphanumeric codes that indicate specific issues with your Glow worm boiler. These codes provide valuable diagnostic information to both homeowners and heating engineers, making it easier to identify and resolve any problems. When an issue arises, the boiler’s control panel will display a fault code, enabling you to understand the nature of the problem.
Imagine this scenario: you wake up one chilly morning, eagerly anticipating a warm and comforting shower. However, as you turn on the tap, you notice that the water remains cold. Frustration starts to creep in, but fear not – the fault code displayed on your Glow worm boiler’s control panel can provide you with valuable insights into the underlying issue.
Whether it’s a faulty sensor, a blocked pipe, or an ignition problem, these fault codes act as a beacon of hope, guiding you towards a resolution.
Recognising Glow worm boiler fault codes is vital for prompt troubleshooting and resolution of issues. By understanding the fault codes, homeowners can determine whether the problem requires professional assistance or if it is something they can resolve themselves. Identifying the fault codes early on can also help prevent further damage to the boiler system and potentially save on costly repair bills.
Imagine this: you’ve just moved into a new home, and you’re still getting acquainted with the quirks and idiosyncrasies of your Glow worm boiler. Suddenly, a fault code appears on the control panel, leaving you perplexed and uncertain about the next steps to take.
But fear not, for armed with the knowledge of these fault codes, you can embark on a journey of troubleshooting and problem-solving. You might discover that a simple reset or a quick check of the pressure gauge is all it takes to restore your boiler to its former glory.
Moreover, recognising fault codes empowers homeowners to communicate effectively with heating engineers, providing them with accurate information that can expedite the boiler repair process. Instead of stumbling through vague descriptions of the issue, you can confidently relay the fault code, allowing the engineer to arrive prepared with the necessary tools and expertise.
So, the next time you encounter a Glow worm boiler fault code, embrace it as an opportunity to unravel the mysteries within your heating system. With a little curiosity and a willingness to learn, you’ll be well on your way to becoming a boiler troubleshooting expert.
Now that we understand the significance of fault codes, let’s delve into some of the most common Glow worm boiler fault codes and what they mean.
One of the most common issues homeowners face with their Glow worm boiler is low water pressure. Code F1 indicates that the water pressure in the system has dropped below the recommended level. This can be caused by a leak in the system or a problem with the pressure gauge. Homeowners can usually resolve this issue by repressurising the boiler, following the manufacturer’s instructions.
When the water pressure in a Glow worm boiler is too low, it can lead to a range of problems. Firstly, the boiler may struggle to heat the water to the desired temperature, resulting in lukewarm showers and baths. Additionally, low water pressure can cause the boiler to work harder than necessary, leading to increased energy consumption and higher utility bills. It is important for homeowners to regularly check the water pressure gauge on their Glow worm boiler and take action if it drops below the recommended level.
In some cases, low water pressure may be a symptom of a larger issue within the heating system. A leak in the pipes or radiators can cause a drop in pressure, and if left unaddressed, it can result in water damage to the property. Homeowners should inspect their heating system for any signs of leaks, such as damp patches or water stains on walls or ceilings. If a leak is suspected, it is advisable to contact a professional plumber to identify and fix the problem.
If your Glow worm boiler displays code F4, it means there is an ignition fault. This fault code indicates that the boiler is struggling to ignite, which may be due to a faulty ignition electrode, a blocked burner, or an issue with the spark generator. It is advisable to seek professional help to diagnose and rectify the ignition fault.
An ignition fault can be frustrating for homeowners, as it means the boiler may fail to provide hot water and central heating. In colder months, this can be particularly inconvenient and uncomfortable. Ignition faults can have various causes, and it is important to address them promptly to avoid further damage to the boiler. Ignition electrodes can wear out over time and may need replacement. Blockages in the burner can prevent proper ignition and may require cleaning or repair. The spark generator, responsible for creating the spark that ignites the gas, can also malfunction and may need professional attention.
Regular boiler maintenance can help prevent ignition faults and ensure the efficient operation of the Glow worm boiler. Homeowners should schedule annual servicing by a qualified heating engineer who can inspect and clean the ignition components, as well as identify any potential issues before they escalate into major faults.
An unrecognised PCB connection is another fault code that Glow worm boilers may display. Code F9 suggests that there is a problem with the Printed Circuit Board (PCB) connection. This could be due to loose wiring or a faulty PCB. In such cases, it is best to contact a qualified heating engineer for assistance with diagnosing and repairing the issue.
The PCB is a crucial component of the boiler’s electrical system, responsible for controlling various functions and ensuring the safe operation of the appliance. When the PCB connection is unrecognised, it can disrupt the communication between different parts of the boiler, leading to malfunctions or complete system failure. Homeowners should avoid attempting to fix PCB issues themselves, as it requires technical knowledge and expertise. A qualified heating engineer will have the necessary skills to diagnose the problem accurately and either repair or replace the faulty PCB.
Regular maintenance and servicing of the Glow worm boiler can help prevent PCB-related faults. During a service, the heating engineer will inspect the PCB for any signs of damage or loose connections. They will also ensure that the boiler’s electrical system meets safety standards and is functioning correctly. By addressing any potential PCB issues early on, homeowners can avoid costly repairs and ensure the longevity of their Glow worm boiler.
While some Glow worm boiler fault codes may require professional intervention, there are a few troubleshooting steps homeowners can take to resolve minor issues themselves.
If you encounter a fault code on your Glow worm boiler, a simple troubleshooting step is to reset the system. This can be done by turning off the boiler, waiting for a few seconds, and then turning it back on again. In some cases, this may clear the fault code and resolve the issue. However, if the fault persists, it is advisable to contact a heating engineer for further assistance.
While some fault codes can be resolved with basic troubleshooting, there are instances where professional intervention is necessary. If you are unsure about the cause of the fault code or if attempts to resolve it yourself have been unsuccessful, it is recommended to call a qualified heating engineer. They have the expertise and knowledge to diagnose and repair complex boiler issues safely and efficiently.
Prevention is always better than cure, and the same holds true for Glow worm boiler faults. By following a few simple maintenance tips, homeowners can reduce the likelihood of encountering fault codes and ensure the smooth operation of their boilers.
To keep your Glow worm boiler running efficiently, it is important to carry out regular maintenance tasks. This includes checking the boiler’s pressure regularly, bleeding radiators to remove trapped air, and checking for any leaks or unusual noises. Additionally, keeping the boiler area free from clutter and ensuring proper ventilation can also contribute to its longevity.
Another crucial aspect of preventing Glow worm boiler faults is scheduling annual servicing. Regular servicing by a qualified professional can help identify any potential issues before they escalate into major faults. A professional service will include checking for gas leaks, cleaning and inspecting components, and ensuring the boiler is operating within safety limits, giving homeowners peace of mind and a well-maintained boiler system.
Finally, let’s address some frequently asked questions regarding Glow worm boiler fault codes.
Can I fix a Glow worm boiler fault code myself?
While some minor issues can be resolved through troubleshooting, it is generally recommended to seek professional assistance when dealing with Glow worm boiler fault codes. Attempting to fix complex issues without proper knowledge and expertise can potentially worsen the problem or compromise safety. It is best to leave faults requiring technical expertise to qualified heating engineers.
How often should I service my Glow worm boiler?
To ensure the optimal performance and longevity of your Glow worm boiler, it is advised to schedule an annual service. Regular servicing allows a qualified professional to inspect and maintain the boiler, identify any potential faults, and carry out necessary repairs or adjustments. By adhering to annual servicing, homeowners can maximise the efficiency and reliability of their Glow worm boiler.
Glow worm boiler fault codes provide homeowners with valuable diagnostic information when issues arise. By understanding these fault codes, homeowners can take appropriate action to troubleshoot and resolve minor issues themselves or seek professional assistance when needed. Performing routine maintenance tasks and scheduling annual servicing are essential in preventing boiler faults and ensuring the efficient and safe operation of your Glow worm boiler. Stay proactive, stay informed, and enjoy a hassle-free heating system.
For professional help and advice, get in touch with the friendly team at Homecure today!
