BoilerFaultCodesYour boiler's internal control board has become too hot to operate safely and has shut down to prevent damage.
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 temperature too high | Cause: Electronic system affected by external heat source, electronic fault
What causes this fault?
This fault occurs when the boiler's main control board reaches an unsafe temperature, forcing the system to shut down to prevent the electronics from melting or catching fire. The most common reason is an internal part becoming too hot due to a failing heat shield or a component on the circuit board itself short-circuiting and generating excessive heat.
This fault is more common during the summer or in very high ambient temperatures, as the control board struggles to stay cool when the surrounding air is already hot.
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.65 — 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.