BoilerFaultCodes.com
LD1 High Lockout

Your boiler has detected a lockout fault and has shut down to protect itself, meaning your heating and hot water will not work until it is reset.

Call an engineer soon

Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Led alarm (red)

What causes this fault?

This fault occurs when the boiler fails to detect a flame after several ignition attempts, causing the system to shut down for safety. The most common reasons are a lack of gas supply to the unit, a blocked burner, or a faulty sensor that cannot confirm the flame is lit. It can also be caused by worn-out electrical components that are responsible for creating the initial spark.

Typical repair cost £100-300 (including labour)

DIY fix possible

Locate the mode selector switch on the front panelTurn the switch to the 'OFF/RESET' positionWait for 5-10 secondsTurn the switch back to either 'Hot Water Only' or 'Heating and Hot Water'

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 LD1 — 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.

Vokera Option 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.

UK's #1 online installer
Boxt
Fixed-price online quotes. Next-day installation.
Get a free quote →
Heatable
Instant online boiler quotes from £1,499.
Get a free quote →
iHeat
Fast installation. Price match guarantee.
Get a free quote →

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

Related fault codes