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Last updated: 3rd August, 2023


Ideal F1 Error Code - How To Fix

Ideal F1 Error Code - How To Fix

Key takeaways

  • The Ideal F1 boiler error code indicates low water pressure.
  • Pressure loss can be caused by issues with the pressure release valve, trapped air or a significant system leak.
  • A boiler filling loop is an excellent bit of kit for topping up boiler pressure.

Anytime a boiler isn’t operating as it should, it can be frustrating as well as time consuming, this is only compounded when you want to heat your home and can’t.

In this blog we’re going to explore the F1 error code displayed by Ideal boilers. We will look at the error code's meaning, what causes it, and troubleshooting tips.

What Is An Error Code?

Before we jump into how to fix one, we’d better explain what one is, just in case you aren’t sure.

An error code (or fault code) is a displayed alphanumeric sequence that intends to alert a boiler owner when their boiler isn’t operating as it should. 

An error code is usually shown on the boiler's display screen, either on the front face of the appliance or beneath a plastic fold-over at the toe end of the boiler.

Ideal F1

The F1 Ideal error code indicates that your boiler is experiencing low water pressure.

System pressure may be lost slowly over a prolonged period before being low enough to trigger the F1 fault code, or pressure could drop very quickly and result in an F1 code.

The F1 error code will result in your boiler 'locking out'. This is where the boiler ceases to function to prevent further system damage or safety hazards.

The F1 error code is displayed on the following boiler models:

  • Ideal Logic +

  • Ideal Logic Max

  • Ideal Logic

Pressure Loss Causes

Low-pressure results in the F1 error code as a prerequisite optimum pressure is needed to maintain a sufficient circulation of water through the property’s central heating system.

Several potential factors, including Issues with the pressure release valve or a leak from either the boiler unit or pipework, could cause Low pressure.

Other causes of low pressure could be air trapped within the system or the system being corroded.

F1 Fixes

As with any boiler error code, the safest option is always to allow a Gas Safe registered engineer to fully assess the situation and provide guidance or carry out any maintenance for any of the issues covered below.

Firstly, you need to check the boiler's pressure gauge, a small dial that looks like a watch face, often with pressure indicators between 0 and 4.0.

If the gauge is reading between 1.5 and 2.0 (in the green zone) but your boiler displays an F1 fault code, this could indicate a faulty pressure sensor.

However, if the gauge shows genuine low boiler pressure below 1.0 (in the red zone), the F1 fault code is correct.


In this instance, a homeowner can easily top up the pressure themselves, but only once the source of the low pressure is located.

Any leak should be treated as serious and needs the attention of an expert engineer before further damage/potential harm can be done.

Topping Up Pressure

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 if any issues arise later. 

Some modern boiler models have internal filling loops, which 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 cannot find it, you can easily find a replacement filling loop online or at your local DIY shop, typically costing £7-£20.


Once the issue has been fixed, you should be able to reset and restart your boiler, resulting in the end of the ‘locking out’ and vanishing of the F1 warning code.

Avoiding Low Pressure

The most prudent method of avoiding boiler error codes is via proactive  preventive maintenance.

Having your boiler annually serviced by a Gas Safe engineer could result in the detection of component issues allowing them to be fixed before they become a hindrance. 

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Frequently Asked Questions

How to resolve F1 error on an Ideal boiler?

To resolve the F1 error on an Ideal boiler, follow these steps:

  • Check the pressure gauge. If it's between 1 and 2 bar, the pressure isn't the issue, and the boiler's pressure sensor might produce incorrect readings.
  • If the pressure is low, you must repressurise the system to fix the error.

What is the F1 fault on the Ideal boiler?

The F1 fault code on an Ideal boiler indicates low water pressure. This issue can arise from the system losing pressure over a prolonged period or if the pressure drops suddenly.

What are common Ideal boiler fault codes?

Aside from the F1 error code, some common Ideal boiler fault codes include:

  • F2: Flame loss
  • F3: Fan fault
  • F4: Flow thermistor issues
  • F5: Return thermistor problems
  • F6: Outside sensor error
  • L2: Ignition lockout
  • L9: System water pressure too high

These codes help diagnose specific issues within the boiler, making identifying and resolving problems easier.

Procedures to repressurise an Ideal Logic boiler

To repressurise an Ideal Logic boiler, follow these steps:

  1. Turn off the central heating and hot water using the control dial.
  2. Locate two blue plastic levers underneath the boiler.
  3. Turn the left lever a quarter turn to open one side of the filling loop.
  4. slowly turn the right blue lever while monitoring the pressure gauge.
  5. Once the pressure reaches the recommended 1-1.5 bar range, close both levers and the boiler should resume normal operation.

How to reset an Ideal boiler with F1 error?

To reset an Ideal boiler with an F1 error, follow these steps:

  • First, repressurise the system to restore the correct water pressure.
  • Once you've done this, you should be able to reset the boiler by pressing and holding the reset button for a few seconds.
  • The boiler should clear the error code and resume functioning correctly.
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Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.