BoilerFaultCodes.com
1023 Low Lockout

Your boiler has been running for a long continuous period and needs to be reset to ensure its internal monitors can perform a safety self-check.

Monitor it

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: Maximum run time including standby time reached

What causes this fault?

This fault occurs when the boiler has been powered on for a very long duration without a break, causing it to reach its programmed software limit for continuous operation. It happens because the system needs to briefly power down and restart to perform essential internal safety tests and recalibrate its sensors. A simple manual reset allows the boiler to complete these checks and return to normal operation.

This code is slightly more common in winter when boilers are under heavy demand and running constantly to maintain home heating without reaching their standby state.

Typical repair cost £0 (including labour)

DIY fix possible

Locate the 'Reset' button on the boiler control panel.Press the reset button once.The boiler should restart and resume normal operation.

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 1023 — no call-out fees, no surprises.

Top rated
OpenFix
Boiler & heating care plans
Get a quote →
Hometree
from £12.95/month
Get a quote →
HomeServe
from £8.00/month
Get a quote →

Affiliate links — we may earn a commission at no extra cost to you.

Related fault codes