Ideal FD Fault Code – What It Means and How to Fix It
If your Ideal boiler shows the FD fault code, it means water isn’t flowing properly through the system. This usually causes the boiler to shut down to avoid damage. The problem is often due to low water pressure, a faulty pump, air in the system, or even a leak.
In many cases, you can fix the issue by checking pressure or bleeding the radiators. In this guide, we explain what the Ideal FD fault code means, how to fix it, and when to call a Gas Safe engineer.

Table of contents
Understanding the Ideal FD Fault Code
The Ideal FD fault code shows up when there is little or no water flow in your boiler. Your boiler needs continuous water circulation to heat your radiators properly. If the water is not moving as expected, the boiler will stop working and display the FD error code. This is a safety feature designed to protect your boiler from overheating or running dry.
You might see this code after a power cut, if you have recently bled the radiators, or if pressure in the system has dropped.
Common Causes of the Ideal FD Fault Code
There are a few common reasons why your boiler might display the Ideal Logic FD fault code.
Low Water Pressure
If the system pressure is below the required level, the boiler cannot circulate water properly. This is often the number one cause of the FD error.
Air Trapped in the System
Air can get stuck inside your pipes or radiators. This blocks water from flowing freely and may trigger the fault code.
Pump Problems
If the pump is not working correctly, water will not move around the system. The pump might be stuck, faulty, or not receiving the signal it needs to operate.
Leaks in the Heating System
Even a small leak can reduce the pressure and cause the boiler to stop detecting water flow.
Power or Installation Issues
Sometimes the fault can appear after a power cut or if there are installation problems affecting circulation.
How to Fix the Ideal FD Error Code
Time needed: 6 minutes
Follow the below steps to fix the Ideal FD Error code
- Check the Water Pressure
Look at the pressure gauge on the front of your boiler. It should be between 1.0 and 1.5 bar when the system is cold. If it is too low, the boiler will struggle to circulate water.
- Top Up the Pressure
If the pressure is low, you can top it up using the filling loop located under your boiler. Slowly turn the valves to allow water into the system. Stop once the pressure reaches the correct level.
- Bleed the Radiators
If some radiators feel cold at the top or make gurgling noises, air may be trapped. Use a radiator key to bleed the air out. Once done, check the pressure again and top it up if needed.
- Check the Pump
Turn on the boiler and listen to the pump. If it is silent, vibrating strangely, or leaking, it may be faulty. A heating engineer can test and replace the pump if needed.
- Look for Leaks
Look around your radiators, visible pipework, and valves for signs of leaks. Even a small drip can affect pressure and water flow. If you find a leak, call a professional.
- Reset the Boiler
After completing the checks and fixing any issues, press the reset button on your boiler to clear the fault. Wait a few moments to see if the boiler starts working again.
When to Call a Gas Safe Engineer For Ideal FD Fault Code
Call a Gas Safe engineer if:
- You can’t figure out why the FD code is showing
- The fault keeps coming back, especially after a power cut
- You’re unsure how to top up the pressure or bleed the radiators
- You suspect a leak or the pump isn’t working
- None of the basic fixes solve the issue
Gas boilers can be dangerous to repair without the right training. A Gas Safe engineer is qualified to inspect and fix the system safely.
Conclusion
The Ideal Logic FD fault code is caused by poor water circulation inside your boiler. In most cases, this is due to low pressure, trapped air, or a faulty pump. You can often fix it yourself by checking the pressure, bleeding the radiators, or topping up the system. If the fault keeps coming back or the boiler does not reset, contact a Gas Safe engineer. Regular checks and annual servicing can help stop this error from coming back.
Frequently Asked Questions
It means the boiler cannot detect enough water moving through the heating system. This stops the boiler to avoid overheating.
No. The boiler shuts down as a safety measure. But if left unresolved, it can lead to more serious issues over time.
Yes. Most people can fix it by topping up the pressure or bleeding radiators. But pump or electrical faults need an engineer.
If it’s just low pressure, it costs nothing. If parts need replacing, costs can range from £100 to £400 depending on the repair.
No. The FD code is a common issue and usually fixable. You only need a new boiler if it keeps failing and is near the end of its life.
The ideal F3 fault code on an Ideal boiler indicates a “Fault with Fan.” Unlike a typical cooling fan. Know everything about Ideal F3 fault code.