BoilerFaultCodesTechnical description
OVERHEATING LOOP: PUMP BLOCKED OR ITS CONDENSER OUT OF SERVICE. ISOLATING COCKS CLOSED ON JIG. DEFECTIVE OVERHEAT THERMOSTAT. BLEED OUT AIR. CHECK THE ELECTRICAL CONNECTIONS.
What causes this fault?
This fault occurs when water cannot circulate through the boiler quickly enough to carry heat away, causing the internal temperature to reach a dangerous level. The most common reasons are a seized internal pump that has stopped spinning or a blockage within the pipework, such as trapped air or closed valves. This trigger is a safety mechanism designed to protect the boiler's internal components from heat damage.
This issue often appears when the heating is first turned on after summer, as pumps can seize up due to 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.