Boiler Parts Advice and Fault Codes

BSH Knowledge Hub is your trusted place for boiler parts advice, boiler fault codes, and practical troubleshooting. We created this hub to help homeowners, landlords, and heating engineers find clear guidance on common boiler problems and part matching. Whether you need help understanding a fault code or identifying a spare part, this page gives you a reliable place to start.

Image showing that Baxi Boiler E384 fault code troubleshooting guide showing a Baxi boiler and information about false flame detection faults.
Adarsh Rangu

Baxi Boiler E384 Fault Code Explained: Causes & Fixes

If your Baxi boiler is displaying the E384 fault code, it means the boiler has detected a false flame signal. This occurs when the boiler believes a flame is present even though the gas valve is closed and no flame should exist. Although the E384 fault is not one of the most common Baxi error

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Image showing that Baxi boiler displaying E168 fault code troubleshooting guide with boiler image and error code information.
Adarsh Rangu

Baxi E168 Error Code: Causes, Fixes & Troubleshooting Guide

If your Baxi boiler is displaying the E168 error code, it usually means the boiler has detected a fault but cannot identify a specific cause. Unlike many boiler fault codes that point to one particular issue, E168 is a general fault code that often appears when there is a problem with the boiler’s electronics, power

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Image showing that Baxi boiler graphic displaying E125 fault code, highlighting circulation problems caused by low pressure, airlocks, pump faults, or blockages.
Adarsh Rangu

Baxi Boiler E125 Fault Code Explained: Causes and How to Fix It

If your Baxi boiler is displaying the E125 fault code, it indicates a circulation problem within the heating system. This fault occurs when the boiler detects that heated water is not circulating properly through the system. Poor circulation can affect heating performance, reduce efficiency, and cause the boiler to shut down as a safety measure.

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Adarsh Rangu

Baxi Boiler E128 Fault Code Explained: Causes and How to Fix It

If your Baxi boiler is displaying the E128 fault code, it means the boiler has experienced a flame loss during operation. In simple terms, the boiler has detected that the burner flame has gone out unexpectedly and has shut down as a safety precaution. The E128 fault can be caused by several issues, including gas

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Image showing that Baxi boiler displaying E119 fault code caused by low water pressure, with troubleshooting guidance on restoring correct system pressure.
Adarsh Rangu

Baxi Boiler E119 Error Code Explained: Causes and How to Fix It

If your Baxi boiler is displaying the E119 error code, it usually means the system pressure has fallen below the recommended level. The E119 error is one of the most common faults found on Baxi boilers and is designed to protect the appliance from operating with insufficient water in the heating system. Fortunately, this fault

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Image showing that Baxi boiler display showing E110 fault code with baxi logo down-left with baxi boiler image
Adarsh Rangu

Baxi Boiler E110 Error Code Explained: Causes and How to Fix It

A Baxi boiler displaying the E110 error code indicates that the appliance has overheated and automatically shut down as a safety precaution. This fault can be caused by several issues, including low water pressure, trapped air in the heating system, poor water circulation, or faulty components such as temperature sensors and pumps. Understanding what causes

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Image showing that Low Pressure Troubleshooting Guide
Adarsh Rangu

Baxi Boiler E118 Error Code: Causes, Fixes & Low Pressure Guide

If your Baxi boiler is displaying the E118 error code, it usually means the system pressure has fallen too low for the boiler to operate safely. This is one of the most common boiler faults and is often straightforward to fix without replacing any parts. In this guide, we’ll explain what the Baxi E118 fault

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Image showing that E133 error code with Complete Guide
Adarsh Rangu

How to Fix Baxi Boiler E133 Error Code: Complete Guide

If your Baxi boiler is displaying the E133 error code, you may suddenly find yourself without heating or hot water. While this fault can be frustrating, it does not always mean there is a major problem with your boiler. In many cases, the issue can be caused by a gas supply interruption, a frozen condensate

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Image showing that What Is an Expansion Vessel How It Works?
Adarsh Rangu

What Is an Expansion Vessel? How It Works, Benefits & Problems

Introduction A boiler has many important parts that work together to provide hot water and central heating. One of the most important but least understood components is the expansion vessel. Most homeowners never see it because it is usually hidden inside the boiler or installed nearby. However, without an expansion vessel, your boiler would struggle

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Image showing that baxi diverter valve image on middle with logo at top-left and text showing that boiler diverter valve and how it works
Adarsh Rangu

Boiler Diverter Valve: How It Works, Uses, Types & Benefits

Introduction When you turn on a hot water tap or switch on your central heating, you expect everything to work instantly. But have you ever wondered how your combi boiler knows whether to send hot water to your radiators or to your taps? The answer is the diverter valve. A diverter valve is one of

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Image showing that Vaillant boiler F75 fault codes with vaillant logo
Adarsh Rangu

Vaillant F75 Fault Code – What It Means and How to Fix It

If your Vaillant boiler is showing the F75 Fault code, it usually means the boiler cannot detect the pressure change it expects when the pump starts running. As a safety measure, the boiler may lock out to protect the system. What does the Vaillant F75 fault code mean? The Vaillant F75 fault code appears when

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Image showing that Vaillant boiler F22 fault codes
Adarsh Rangu

Vaillant F22 Fault Code – Meaning, Causes and How to Fix It

If your Vaillant boiler is showing the F22 fault code, it usually means the system has low water pressure. When the pressure drops too low, the boiler shuts down to protect itself, which can leave you without heating or hot water. In many cases, the issue can be solved by repressurising the boiler using the

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BSH Knowledge Hub

Our knowledge hub covers many of the UK’s most common boiler brands, including Baxi, Worcester, Vaillant, Ideal, and more. We focus on the issues people face every day, such as low pressure, ignition faults, leaking parts, heating loss, and error codes. The aim is to make boiler support easier to understand, so you can quickly find useful answers without wasting time.

Here, we discuss common boiler issues and simple checks that may help before paying for an engineer callout. You can learn what certain symptoms may mean. Also what part could be causing the fault, and when a replacement may be needed. For safety, any gas-related issue, internal repair, or unsafe fault should always be handled by a qualified heating engineer.

This hub is also open to engineers who want to share real fault cases and practical solutions from their own experience. That helps us keep the advice useful, current, and based on real boiler problems. To learn more about our business, visit our About Us page. If you already know what you need, you can find your boiler parts here.

If you are a Gas Safe engineer and would like to share your knowledge with our community, we would be happy to hear from you. We welcome practical advice, fault-finding tips, and real repair experiences that can help homeowners, landlords, and other engineers. If you would like to contribute to our knowledge hub, please send us a message through our Contact Us page. Our team will get back to you as soon as possible.

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