BoilerFaultCodes.com
1 Red Flash Low Warning

Your boiler is experiencing a temporary temperature reading issue and is currently trying to fix itself automatically.

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: Sensor error, sensor fault, temperature fault or flow fault – this is a temporary error, the system should reset on it’s own.

What causes this fault?

This fault occurs when the boiler's internal sensors detect a sudden or unusual temperature reading that doesn't match expected levels. It is usually caused by a 'hiccup' in the temperature sensor's communication with the main control board or a momentary restriction in water flow. Because it is often a temporary glitch, the boiler pauses briefly to see if the reading stabilises before trying to fire up again.

Typical repair cost £90-180 (including labour)

DIY fix possible

Wait 5-10 minutes to see if the boiler automatically resets itselfCheck that your radiators are bled and there is no trapped air in the systemEnsure your boiler pressure is between 1.0 and 1.5 bar on the pressure gauge

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 1 Red Flash — 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.

Baxi MainEco 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