Common boiler error codes & what to do

Boilers can show error codes from time to time. Some problems are easy to fix and you can carry out a few simple steps to do it yourself, while others need to be sorted out by a Gas Safe registered engineer. This article will help you determine whether there’s a problem with your boiler, gas supply or heating system and how to resolve it.

Most error codes will appear on the facia display as either two or three numbers, preceded by the letter ‘E’.

Here is a list of some of the most common error codes, and the recommended action to take. If the error code persists or does not indicate an issue you can fix yourself, please call Plus Heat on 0808 164 2892 and we can arrange for one of our Gas Safe engineers to visit.

Common Error Codes

E110, E125, E131

• Boiler: Generic
• Recommendation: Bleed radiators & reset

These 3 separate boiler error codes indicate overheating. To resolve this, bleed your radiators of air and reset the boiler. The error code should then disappear. E110, E125, and E131 error codes signify potential overheating issues in boilers. To resolve this, immediately turn off the boiler and bleed radiators to release trapped air, optimizing water circulation.

Check the pump for malfunctions, verify the thermostat's accuracy, and reset the boiler. If problems persist, consult your boiler's manual for specific instructions or seek professional assistance to prevent damage and ensure safe, efficient heating.

E119

• Boiler: Generic
• Recommendation: Top up boiler pressure

This error code signifies low water pressure. Add water into the system until the pressure gauge indicates a healthy water level, normally between 1 & 2 bar. If you are having to do this more than once every 2 months or if you can see signs of a leak, call out an engineer.

E133

• Boiler: Generic
• Recommendation: Reset boiler

This error code means the boiler has failed to ignite. Check if there is a gas supply to other appliances (i.e. Hob) and that the gas meter is turned on (and is in credit), then reset the boiler. If there is a rumbling sound or if the error code persists, call out an engineer.

E117

• Boiler - Baxi
• Recommendations - requires a Gas Safe registered engineer

The "E117" boiler error code, often seen in Baxi boilers, indicates that the water pressure is too high. To resolve this issue, bleed the radiators to reduce excess pressure. Ensure the boiler is off while doing this. If the pressure remains too high, consult a professional heating engineer to inspect and address any potential problems with the boiler's pressure relief valve or other components.

LC & L2

• Boiler: Ideal
• Recommendation: Reset boiler

These error codes signify an ignition lockout, usually caused by the boiler switching off. If you are on a prepayment meter check whether that has recently run out of credit, or check the settings on your thermostat. In either of these cases, when you have resolved the issue a simple reset of the boiler should see your boiler working again.

F1

• Boiler: Ideal
• Recommendation: Top up boiler pressure

This error code signifies low water pressure. Add water into the system until the pressure gauge indicates a healthy water level, normally between 1 & 2 bar. If you are having to do this more than once every 2 months or if you can see signs of a leak, call out an engineer.

LF

• Boiler: Ideal
• Recommendation: Reset boiler

This error code means the boiler has failed to ignite. Check if there is a gas supply to other appliances (i.e. Hob) and that the gas meter is turned on (and is in credit), then reset the boiler. If there is a rumbling sound or if the LF code persists, call out an engineer.

EA 227

• Boiler: Worcester Bosch
• Recommendation: Reset boiler

These error codes signify an ignition lockout, usually caused by the boiler switching off. If you are on a prepayment meter check whether that has recently run out of credit, or check the settings on your thermostat. In either of these cases, when you have resolved the issue a simple reset of the boiler should see your boiler working again.

E117

• Boiler: Baxi
• Recommendation: Bleed radiators

This error code indicates water pressure is too high. To reduce the water pressure, bleed the radiators of any air and if necessary, some water until the pressure is within the recommended range (normally between 1-2 bar). The boiler should be off when you do this.

E118

• Boiler: Baxi
• Recommendation: Top up boiler pressure

This error code signifies low water pressure. Add water into the system until the pressure gauge indicates a healthy water level, normally between 1 & 2 bar. If you have to do this more than once every 2 months or if you can see signs of a leak, call out an engineer.

E135

• Boiler: Baxi
• Recommendation: Reset boiler

These error codes signify an ignition lockout, usually caused by the boiler switching off. If you are on a prepayment meter check whether that has recently run out of credit, or check the settings on your thermostat. In either of these cases, when you have resolved the issue a simple reset of the boiler should see your boiler working again.

E256

• Boiler: Vaillant
• Recommendations - requires a Gas Safe registered engineer.

This error suggests a lack of water circulation. Ensure that the system's pump is functioning correctly and check for blockages in the pipes. To fix the E256 error on a Vaillant boiler, check the circulation pump for issues, clear blockages, bleed radiators, and ensure valves are fully open. Verify system pressure and reset the boiler. If the problem persists, consult a qualified engineer for professional assistance.

F27

• Boiler - Valiant
• Recommendations – requires a Gas Safe registered engineer.

The "F27" boiler error code, commonly seen in Vaillant boilers, points to a problem with the gas supply or ignition. To resolve it, first ensure the gas supply is uninterrupted. If the issue persists, consult a qualified heating engineer to investigate and rectify any issues with gas pressure, ignition components, or the gas valve, ensuring the boiler operates safely and efficiently.

F75

• Boiler - Valiant
• Recommendations -

This often indicates a sensor issue, where the boiler's sensor fails to detect the pump's operation. Your boiler's manual lists all fault codes, assisting engineers in diagnostics and offering users insights for booking repair visits. For specific error resolution, refer to the manual or the manufacturer's website for guidance and practical tips.

E20

• Boiler - (Glow-worm):
• Recommendations - top up water pressure if required

An E20 error typically points to a lack of water pressure. Check the system's pressure gauge and top up the pressure if necessary. To resolve the "E20" boiler error code, indicating low water pressure in a Glow-worm boiler, start by checking the pressure gauge, which should ideally read between 1 to 2 bar. If it's too low, carefully top up the system with water to achieve the correct pressure.

Inspect the system for visible leaks, and if any are found, address them promptly. After ensuring the pressure is within the recommended range and fixing any leaks, reset the boiler to clear the error code. However, if the issue persists or is challenging to resolve, it's advisable to seek the expertise of a qualified heating engineer who can conduct a thorough examination and perform necessary repairs.

F28

Boiler - Worcester Bosch
F28 indicates a lack of communication between the boiler and its main components. You may need to reset the boiler. The "F28" boiler error code, commonly seen in Worcester Bosch boilers, often indicates a communication issue between the boiler and its primary components. To resolve it, try resetting the boiler. If the error persists, contact a qualified heating engineer to diagnose and rectify the problem, ensuring that your boiler operates smoothly and efficiently.

A01

Boiler - Alpha
The "A01" boiler error code, found in Alpha boilers, typically points to an ignition failure. Check for gas supply issues and the condition of the ignition electrodes. First, ensure the gas supply is uninterrupted. Check the condition of the ignition electrodes and clean or replace them if necessary.

If the issue persists, or if there are underlying problems with the gas supply, it's advisable to seek assistance from a qualified heating engineer to ensure the safe and efficient operation of the boiler.

It's important to remember that while these error codes and recommendations can be a helpful starting point for troubleshooting boiler issues, if the problem persists or if you are unsure about any aspect of your boiler's functioning, it's always wise to seek the expertise of a qualified engineer. Regular boiler maintenance and servicing can help prevent many of these issues, ensuring your heating system runs smoothly and efficiently.

Also Read -

• Plumbing and Drainage Comparison
• How Do Thermostatic Radiator Valves Work?
• Do You Need a Boiler Cover?