BoilerFaultCodes.com
01 High Lockout

Your boiler is failing to light the gas flame, which means you have no heating or hot water until the system is reset or repaired.

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: Failure to ignite

What causes this fault?

This fault occurs when the boiler's control system attempts to light the gas but cannot detect a stable flame. The most common reasons include a lack of gas supply reaching the unit, worn-out electrodes that can no longer produce a spark, or a faulty gas valve that isn't opening correctly.

This fault is more common during the first cold snap of autumn when components that have been sitting idle over summer are suddenly forced to work under high demand.

Typical repair cost £100-280 (including labour)

DIY fix possible

Check if your gas supply is turned on at the meterTurn the mode selector switch to the 'OFF/RESET' position and then back to 'ON'Check if other gas appliances in your home are working correctly

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 01 — 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 Mynute 28E / 35E 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