BoilerFaultCodesTechnical description
NTC1 short-circuited (NTC1 = outlet sensor) Probe manifold short-circuited
What causes this fault?
This fault occurs when the boiler's internal temperature rises too quickly or exceeds a safe limit, causing the system to shut down to prevent damage. The most common reasons are a pump failure that stops water from moving or a buildup of debris and sludge that creates a blockage within the heat exchanger. This lack of circulation means the heat produced by the burner has nowhere to go, triggering the safety sensors.
This issue often appears when the heating is first turned on after summer, as pump components can seize up during long periods of inactivity.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.