Ideal boiler fault & error codes

Noticing that there’s a fault with your Ideal boiler is less than ideal, but getting it sorted doesn’t have to be as much of a hassle as you’d expect.

It’s important to note that once you’ve discovered an issue with your system, a Gas Safe registered engineer needs to be called to diagnose and rectify the problem fully.

To make the process of diagnosing any problems as painless as possible, Ideal pre-programs its boilers with fault and error codes. These codes are displayed on the user interface to alert you and your engineer to anything that needs attention within the system.

Here, we’ll cover all of the most common Ideal boiler fault codes, discussing their meaning and advising on any next steps that you or a Gas Safe registered engineer can take to get things back to working as they should.

Ideal boiler fault & error codes by boiler model

• Ideal boiler F fault codes
• Ideal boiler L fault codes
• Ideal boiler C fault codes
• Additional Ideal boiler fault codes

Ideal boiler F fault codes

Error code	Problem	Solution
F	Boiler operating in frost mode.	Contact an engineer.
FD	No water flow	Repressurise the boiler. If this doesn’t resolve the issue, call an engineer.
FU	Flow/return differential – 50°C	Contact an engineer.
F1	Low boiler pressure	Top up the water pressure.
F2/FL	Flame loss	Reset the boiler. If this doesn’t resolve the issue, call a Gas Safe engineer.
F3	Fan fault	Contact an engineer.
F4	Thermistor fault	Contact an engineer.
F5	Return thermistor fault	Contact an engineer.
F6	Outside sensor fault	Contact an engineer.
F7	Low mains voltage	Contact an engineer.
F8	Printed circuit board (PCB) fault	Contact an engineer.
F9	Unconfigured PCB.	Contact an engineer.

Ideal boiler L fault codes

Error code	Problem	Solution
L1	Low water flow	Reset the boiler. If this doesn’t resolve the issue, call an engineer.
L2	Ignition lockout	Reset the boiler. If you hear a rumbling noise, call an engineer.
L3	No flow thermistor fault	Contact an engineer.
L9/H9/HA/LA	Overheating	Check pressure readings and bleed your radiators. If no change, call an engineer.
LF	Ignition fault	Reset your boiler. If your boiler is rumbling, contact a qualified engineer.
L4	Flow thermistor fault	Restart the boiler. If the issue continues, contact an engineer.
L5	Boiler return pipe issue	Turn off the boiler’s power at the fuse spur, then turn it back on. If the issue persists, call an engineer.
L6	Flame detection fault	Reset your boiler. If the problem persists, contact an engineer.
LC	5 boiler resets in 15 minutes.	Turn the electrical supply to the boiler off and on. If the boiler fails to operate, contact a Gas Safe registered engineer.
L9	Unconfigured PCB	Contact an engineer.
L-F	Boiler fails to ignite	Try resetting the boiler. If nothing changes, contact an engineer.
L-A	Boiler overheated	Check that there is sufficient water pressure in the central heating system and that all radiators have been bled. Then, reset the boiler. If the issue persists, contact an engineer.

Ideal boiler C fault codes

Error code	Problem	Solution
C2	Boiler chip card fault.	Reset your boiler. If the issue persists, contact an engineer.
C0	Central heating signal issue.	Contact an engineer.
C	The boiler is operating in central heating mode. Or the boiler has a call for central heating, and the appliance has reached the desired set temperature.	No solution needed. This is a setting, not a problem.

Additional Ideal boiler fault codes

Error code	Problem	Solution
D	The boiler is operating in hot water mode, or the boiler has a call for hot water and the appliance has reached the desired set temperature.	No solution needed; this is a setting.
0	The boiler is in standby mode awaiting hot water requests or a central heating call.	Choose your settings.
H-3	Domestic hot water thermistor error.	Reset the system.
No display	No heating or hot water.	This is a PCB error. Call an engineer.

Protect your home’s central heating with BOXT

Luckily, the majority of Ideal boiler problems are relatively quick and easy for qualified engineers to fix, provided they’re identified promptly. If you suspect that any of the issues mentioned above are to blame for your boiler’s malfunctioning, and the recommended fix isn’t as simple as pressing the reset button, always contact a Gas Safe registered engineer who’ll be able to come and assist you.

Sometimes, it’s better to be safe than sorry. We all know that household issues arise when you’re least prepared for them, so it helps to have a good idea of how your boiler is performing. 

If you’re unsure about the current performance of your boiler, why not book a boiler service? With the help of our engineers, you’ll be sound in the knowledge that your boiler is doing the most it can possibly do for your home.