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Last updated: 25th March, 2024


E1 Error Code - How To Fix

E1 Error Code - How To Fix

Key takeaways

  • The E1 boiler code can be triggered by a number of different faults, each identified with the digit sequence following the 'E1', for example E133.
  • If the problem is low pressure, you can quickly top this up using a boiler filling loop.
  • Modern boilers are far less susceptible to breakdown or component failure.

When a boiler starts displaying an error code out of the blue it can be a shock to the system, especially if you can’t heat your home the way you’d like to.

When a boiler starts displaying an error code out of the blue it can be a shock to the system, especially if you can’t heat your home the way you’d like to.

In this blog we’ll be taking a look at how to diagnose and fix the E1 boiler error code, a common and frustrating occurrence that may not be as daunting once you know more about it.

What Is An Error Code?

To start things off we’ll explain what an error code is, their function and where to find them.

An error (fault) code is as simple as its name suggests, an alphanumeric digit code e.g E110, which is displayed when a boiler is not functioning as it should.

An error code can usually be located on the boiler's display screen, a small, often backlit digital window found either in the centre of the boiler casing or at the toe of the boiler covered by a small plastic panel.

E1 Error Code Causes

They can be definitely stressful, however this particular fault code cluster, the E1 catalogue, isn't as sinister as some other fault codes.

Most of the time the E1 error code connotes low boiler pressure which can result in the boiler ‘locking out’ or shutting down to avoid further damage or safety problems.

Occasionally an E1 code may be indicating a different type of component or unit failure, this is why it’s important to assess the digit sequence following the ‘E1’ part of the code for example E133.

E1 Variants:

E110 - Water flue or System has overheated

E160, E50, E28, E20 - Faulty component

E133 - Ignition failure, interrupted gas supply, flame undetected, frozen condensate pipe 

E168 - Undeterminable fault (electric supply/external issue)

E119 - Pressure below 0.5 bar

E1 Fixes

E110, E133 - rotate selector dial to reset position and hold for 5 seconds.

E160, E50, E28, E20, E168 - take note of exact error code and contact an engineer

E119 - Repressurise the system via filling loop

If none of these fixes solve the problem then it’s time to contact a Gas Safe registered engineer.

Repressurising system

A boiler filling loop is a tool used to provide a temporary connection between the boiler and the mains water supply, allowing you to repressurise your boiler and fill your heating system with water.

You can find out how to easily use a boiler filling loop in our simple step by step blog.

Typically, the engineer that fits your boiler will leave the filling loop nearby so you can easily access it should any issues arise later down the line. 

Some modern boiler models have internal filling loops, this means the braided coil piping that external loops are made of is already attached in place, all you need to do is open and close the mains valves. 

However, if you are unable to find it, you can easily find a replacement filling loop online or at your local DIY shop, typically costing £7-£20.


How to Avoid fault codes appearing on your boiler

The easiest way of ensuring your boiler is in optimal working order is by arranging for it to be annually serviced by a Gas Safe engineer, these in depth diagnostic assessments can detect faults early and can lead to preventive proactive maintenance.

New and efficient boilers have been designed with longevity and performance in mind. It’s a scientific and engineering fact that modern boilers are constructed in accordance with leps in technology, ensuring your new boiler will stand the test of time.

iHeat New Boiler Costs

Boilers can be a daunting purchase for many people as they’re an appliance with a lot of responsibility, providing heat for you and your family is something you want to get right. Boilers aren’t exactly a quickly disposable item either, potentially lasting you a decade.

Effectively, new boiler cost can be split into two segments: the first is the actual boiler itself (unit price), and the second is the cost of the boiler being installed (set up) in your property by an expert engineer. 

Here at iHeat, we want to remove all of this undue stress and make the decision making process of upgrading to a new central heating system, as easy as possible.

Boiler costs can vary depending on a number of factors including their brand, model, fuel, output, warranty, labour and installation type. Typically a new boiler will cost between £1,845 and £3,500, below is a list of average boiler installations offered by iHeat (guide only).

Installation Type

Price (inc VAT)

Combi to combi swap


Get a quote

System to combi conversion


Get a quote

New boiler install


Get a quote

Back boiler to a combi


Get a quote

System to system


Get a quote

Frequently Asked Questions

What causes an E1 error code on boilers?

An E1 error code on boilers usually suggests issues with the appliance's internal components or system, such as a malfunctioning pressure sensor, faulty temperature probe, or problems with the heat exchanger. Incorrect installation or improper maintenance can also cause this error.

What do I do when encountering E1 19 error on boiler?

When an E1 19 error occurs, turn off the boiler and consult the manual. The error might be due to issues with the expansion vessel, condensate pipe, or water pressure. These problems might need professional attention. If unsure, always contact a heating engineer.

How do you fix E1 on a boiler?

First, identify the cause, which typically relates to low pressure. Check and adjust the pressure, inspect for leaks, and reset the boiler. If these steps don't resolve the error, contact a heating engineer.

How do I reset my E1 boiler code?

To reset the E1 error code, check and repressurise the boiler if necessary. Then reset the boiler using the provided button. If the error persists, consult a professional heating engineer.

What is the most common boiler fault?

The E1 error code, indicating low water pressure, is a common boiler fault across various brands. This error can usually be fixed by resetting the boiler, but regular inspections and annual servicing are recommended for long-term efficiency and safety.

Stephen Day profile photo
Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.