BoilerFaultCodesYour boiler has detected an electrical issue with its internal heat sensors or the main control board, preventing it from heating your home safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Electronic system/sensor fault | Cause: Short circuit in flow or backflow NTC, electronic fault
What causes this fault?
This fault occurs when the boiler's internal computer receives conflicting or impossible signals from its temperature sensors. It usually happens because a sensor has suffered an electrical short circuit or the main control board has developed a hardware malfunction, making it impossible for the system to monitor heat levels safely.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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 F.64 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Vaillant Ecomax 613 2 E 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.