General Heating FAQ'S

Boilers come up with all-manners of error codes, each with a different meaning. Let’s take a look at some of the most common and how to identify them:

E-Error Codes

“E-Error” codes vary significantly and can refer to a plethora of different things. In general, they can be separated into three categories: 

• E+2: E+2 numbers (e.g., E20) typically refer to errors that will require a certified engineer to rectify. They include such issues like internal sensor errors. 

• E+3: E+3 numbers (e.g., 110) usually indicates a fault that can be easily fixed by you. For example, E110 tells you that your system is overheating which can be fixed by bleeding the radiators. 

• E+3 High: E+3 numbers that have a higher number (e.g., E167) are often programming errors and will definitely require a certified engineer to resolve. 

EA (Worcester) or F27 (Valiant)

This error code indicates that there is a blocked condensate pipe. This is usually a problem when temperatures drop below zero. 

You will need to thaw the pipe with great care if it is accessible. A great way to do this is using a hair dryer as opposed to using boiling water. 

A1 or No code (Worcester) or F75 (Valiant) F1 (Ideal)

These error codes refer to low water pressure. This means you need to top up your boiler which usually requires that you turn a specific handle on your boiler. Follow your instruction manual or refer to a specialist. 

EA (Worcester) or F75 (Valiant) 

These error codes mean that your boiler’s sensor is failing to connect with the pump while it is running. This will require an engineer to inspect. 

The most common Worcester Bosch errors 

• A1: this code indicates that there is low water in the system and that it needs to be re-pressurised. Simply press the gauge and re-pressurise to 1.8 / 2 bars. 

• C1: this code means that the fan has stopped working. 

• EA: this means that there is no flame detected in your system. 

• No code: no code can either refer to a low water or low pressure error. Check your pressure gauge and then re-pressurise to either 1.8 / 2 bars. 

• 260: this means that there is either a sensor disconnected or that there is no water left in the boiler. Begin by checking the pressure gauge and then re-pressurise it to 1 bar. 

• C6: this refers to your boiler either running too fast or slow. You will need to call an engineer immediately. 

• C7: this error code means that the fan is not running and/or the airflow has been blocked. Call an engineer to rectify this issue immediately. 

• D1: this means that your sensor is either wet or has become damaged. It can also mean that the system has overheated. Either way, call an engineer. 

• E2: E2 means that your flow sensor has either shorted, become damaged, or disconnected. Again, you will need to call for an engineer’s assistance. 

• E5: this error code means that your primary flow sensor has overheated which will require the assistance of an engineer. 

• E9: E9 refers to your main heat exchanger overheating with a maximum temperature of 105°C. Either that, or the maximum temperature sensor for the main exchange has failed completely. 

In any case, it’s always best to call an engineer to come out and inspect your boiler – particularly if the boiler issue is coming from inside. 

As for Gas boilers, you should ONLY call a Gas Safe engineer. Never attempt to fix yourself – or call someone without this certification. 

Other common error codes 

• E110, E125, E131: these are generic boiler error codes and typically require that you bleed radiators and reset the system. All three codes indicate overheating – once bled and reset the error codes should disappear. 

• E119: this is a generic boiler code and signifies low water pressure. Simply add water to your system until the pressure gauge sits around the 1 & 2 bar mark. If this is something that you are having to do quite regularly then it’s a clear sign of a leak and you should contact your engineer. 

• E133: this generic boiler error code typically means that the boiler itself has failed to ignite. The necessary steps are to check if there is a gas supply – or check your other gas appliances such as the hob and that the gas metre is turned on. Then, reset the boiler. If there are any rumbling sounds or if this error code persists, call an engineer immediately. Remember, it’s never worth playing around with a gas boiler unless you are certified to do so. 

• LC & L2: this is an ‘Ideal’ boiler error code and indicates that there has been an ignition lockout. This is typically caused by the boiler switching itself off. If you are on a ‘prepaid’ metre, double check to make sure you haven’t run out of credit. Or alternatively, check the settings using your thermostat. If it was a case of running out of credit, simply top up and reset. If you are in credit and the error persists, contact an engineer. 

• F1: F1 is another ‘Ideal’ boiler error and typically indicates low water pressure. Simply add water to the system until your pressure gauge indicates a suitable water level. If this is a problem that keeps persisting, you likely have a leak and should contact your local engineer. 

• LF: LF is a common error code for ‘Ideal’ boilers and usually refers to the boiler failing to ignite. Check your gas supply and/or other appliances. If your gas metre is turned on and in credit, reset the boiler. For any rumbling sounds or a persistent LF code, contact your engineer. 

• EA 277: EA 227 is a common error code for ‘Worcester Bosch’ boilers. This indicates that there’s an ignition lockout. This is typically caused by the boiler switching itself off. If you are on a ‘prepaid’ metre, double check to make sure you haven’t run out of credit. Or alternatively, check the settings using your thermostat. If it was a case of running out of credit, simply top up and reset. If you are in credit and the error persists, contact an engineer.  

• E117: this is a ‘Baxi’ boiler issue and refers to water pressure being too high. The easiest fix is to bleed the radiators as necessary. If necessary, bleed some water until the pressure has dropped within the recommended range (between 1 and 2 bars). Remember, the boiler should be switched off while you do this. 

• E118: this common ‘Baxi’ boiler error code indicates low water pressure in the system. Simply add water to your boiler until the water pressure reaches the recommended level (between 1 and 2 bars). If this is something that happens often, you may have a leak and should contact your local engineer. 

• E135: this is a common ‘Baxi’ boiler error code and typically indicates an ignition lockout. his is typically caused by the boiler switching itself off. If you are on a ‘prepaid’ metre, double check to make sure you haven’t run out of credit. Or alternatively, check the settings using your thermostat. If it was a case of running out of credit, simply top up and reset. If you are in credit and the error persists, contact an engineer.  

• F75: this generic error code indicates there has been no pressure change detected when the pump starts. In other words, your boiler isn’t recognising any pressure when there is water flowing through the system. Contact your engineer. 

• F27: this boiler error code means that there has been an incorrect flame detected. This indicates that there is an imbalance between the gas and flame and isn’t at the right level for the boiler to function optimally. Contact your engineer immediately.