Main Boiler Fault Codes / Error Codes Re July 19, 2021

Main Boiler Fault Codes / Error Codes


What are the Main Boiler Error Codes? This blog provides a complete list of fault codes for all makes of Main boilers.

The Main boiler range consists of three boiler models with outputs of between 15kW and 30kW. There is the Main Eco Compact Combi with power outputs of 25kW and 30kW, the Main Eco Compact System boiler, with power outputs of 15kW and 18kW and then Main Eco Compact Heat only boilers that have outputs of 15kW, 18kW, 24kW, and 30kW. 

All Main boilers are endorsed by the Energy Saving Trust, meaning that they are efficient and reliable gas boilers that could potentially help reduce your energy bills and carbon footprint. However, you may be reading this, standing next to your conked-out boiler, questioning whether or not you agree with this.

This blog is here to help you to identify any issues that you may be experiencing with your boiler so that you can inform your Gas Safe Engineer of the issue and they can resolve this for you. On the other hand, you might already be at the point where you’re tired of having to fork out a load of money on your boiler and think it might be easier to get a new one. In some cases, it may be more cost-efficient to get a boiler replacement.  

If you are looking for a quick boiler quote, WarmZilla can take you through a simple online survey to help you find the best new boiler suitable for your home. 

There are many factors to think about when investing in a new boiler. If you are unsure of what boiler you need for your home, the blogs listed below may help you gather more knowledge and decide on the perfect boiler for your home.

Warning, self-promo coming. If you are unsure what kW output means or you’re unsure what kW output is best suited for your home, don’t stress, we have your back. Here are some blogs that could help.

Main boilers are a part of Baxi Heating, which claims to be one of the best known and trusted heating and hot water brands for residential and commercial heating in the UK and Ireland. 

They state that sustainability is embedded in all that they do and that they are committed to being a cleaner, greener manufacturing business that is developing technologies to help customers heat their homes without warming the planet. 

Sounds great hey? Until your boiler breaks down… Well, panic no more, this blog is here to save the day! 

Before we get into the dreaded error code section of this blog, let’s take a look at what customers think about their Main boilers. 

During the Which? Best Buy survey 2020, over 7,500 boiler owners and 152 Which? Trusted Traders heating engineers were asked what they thought about their Main boiler. 
Main scored an overall brand score of 48%, which is significantly less than their parent boiler brand, Baxi, who scored an overall 71%. Here are the survey results:

Which? Best Buy Survey 2020 Results:

Overall Score48%
Reliability3 stars
Customer Score2 stars
Engineer recommendation3 stars
Ease of fixing a common fault4 stars
Ease of servicing 3 stars
Availability of spares and parts 4 stars
Build quality3 stars

Although these scores suggest that customers were not as impressed with their Main boilers as they would have been with other well-known brands such as Worcester Bosch and Ideal, we can see that engineers have rated this boiler highly suggesting that it is easy to install and spares and parts are easy to get hold of. 

Now that you have a bit of background on Main boilers, let’s get into the Main error codes. We provide these error codes to help you identify the issue with your boiler and hopefully fix it yourself. If you identify an internal issue with your Main boiler then you will need to contact a Gas Safe Engineer to come and take a look.

Main Boiler Error Codes

Fault CodeSystem Behaviour
E168Error code E168 could mean that your boiler has detected a problem but can’t work out exactly what it is;
E20Central Heating NTC Fault indicates faulty components. You
should make a note of the displayed error code
E28PCB Fault indicate faulty components
E50Hot Water NTC Fault indicate faulty components
E110Safety Thermostat operated – displayed when the primary water pressure is less than 0.5 bar. After repressurising the system the boiler should operate. Your installer will be able to advise you about the method of repressurising
E119Water pressure switch not operated – displayed when the primary water pressure is less than 0.5 bar. After repressurising the system the boiler should operate. Your installer will be able to advise you about the
method of repressurising
E33Interruption Of Gas Supply or Flame Failure indicates that the gas supply has been interrupted, ignition has failed or the flame has not been detected. Ensure that the gas supply has not been turned off, and turn the selector switch to the reset position and hold for at least 5 seconds. If the boiler does not relight, or the code is displayed regularly.


Fan or fan wiring fault

Main Eco Compact Boiler Error Codes

Fault CodeSystem Behaviour
E09Gas valve connection error
E15VGas valve error
E20Central heating negative thermistor coefficient (NTC) sensor error
E28Flue negative thermistor coefficient (NTC) sensor error
E40Central heating return sensor error
E83Communication error
E109Pre-circulation fault
E110Safety thermostat operated
E118Primary system water pressure too low
E125Circulation error
E128Flame error
E130Flue negative thermistor coefficient (NTC) sensor operated
E133Interruption of gas supply or flame error
E135Interruption of gas supply
E154Flow return sensor temperature test
E160Fan or fan wiring error
E270Circulation fault (dry fire)
E321Hot water negative thermistor coefficient (NTC) error
E384False flame

Main Error Code E133

If your Main boiler is showing the error code E133 means that the condensate pipe has frozen. This is an issue that can happen during the cold winter months as the condensate pipe leads outside but luckily this is an issue that can be resolved fairly quickly without the need for an engineer. If you want to learn more about how to unfreeze your condensate pipe, we have a blog that might help you out 😊

This is probably the best time to mention that WarmZilla has a Best Price Guarantee offer that ensures that we will beat any boiler price by £50 if you manage to find a boiler cheaper elsewhere (which you won’t). 

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