Your boiler has been reset too many times in a short period and has temporarily locked itself to prevent damage.
This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.
Technical description: Maximum locking number reached – boiler has reached the maximum reset number (5 times in an hour) – attempt 1 reset each hour thereafter.
What causes this fault?
This fault occurs when the boiler has been manually reset five times within a single hour, causing the system to temporarily lock you out for safety. It usually stems from an underlying ignition or flame issue that keeps causing the boiler to fail, leading the user to keep pressing the reset button. The root cause is typically a worn-out ignition part or a fault with the gas supply that prevents the boiler from staying lit.
DIY fix possible
Wait for 60 minutes without touching the boiler to allow the internal timer to clear.Check that your gas pre-pay meter (if applicable) has credit.Ensure any external gas valves are open and that other gas appliances are working.After the hour has passed, perform one single reset to see if the boiler fires up.
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 rE28 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.