BoilerFaultCodesYour boiler’s control panel has been locked manually or due to a button sequence error, preventing you from changing any settings.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Control panel locked.
What causes this fault?
This code appears because the child lock or control panel lock has been activated, either intentionally or by mistake. It happens when specific buttons on the front of the boiler are held down for too long, which disables the interface to prevent accidental changes to your heating settings. In rare cases, the code can persist if one of the physical buttons has become stuck in the pressed position.
DIY fix possible
Locate the 'Mode' or 'Reset' buttons on the control panel.Press and hold the 'Mode' button for approximately 5 to 10 seconds.Wait for the display to change or for the '5 A' code to disappear, indicating the panel is unlocked.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 5A — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Ideal Maximiser SE is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.