BoilerFaultCodesYour boiler is currently running at its lower power setting to maintain temperature efficiently.
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: 1st stage operating indicator (low fire). Indicates low fire in operation.
What causes this fault?
This is not actually a fault, but a status indicator telling you the boiler is running at its minimum burner setting. It occurs when the water has almost reached the desired temperature, so the boiler 'turns down the flame' to use less gas while keeping your home comfortable. This is a sign that the system is modulating correctly to save energy.
This code is more common during milder weather or when the house is nearly up to temperature, as the boiler doesn't need to work at full strength.
DIY fix possible
This fault may be fixable without an engineer. Check your manual first.
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 B4 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Ideal Falcon Gte 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.
Affiliate links — we may earn a commission at no extra cost to you.