BoilerFaultCodesYour boiler is overheating because the water inside is heating up faster than it can be moved around the system.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: The temperature recorded by the flow temperature sensor or the safety sensor is rising too quickly
What causes this fault?
This fault occurs when the heat inside the boiler cannot be carried away quickly enough, causing the internal temperature to spike dangerously fast. The most common reasons are a failed pump that isn't pushing water through the pipes or a blockage, such as sludge or limescale, that is restricting the flow. Essentially, the boiler is generating heat but has nowhere to send it, so it shuts down to prevent damage.
This issue often appears at the start of autumn when the heating is turned back on after a long summer break, as internal pump components can seize up during periods of inactivity.
DIY fix possible
Check that all radiator valves are fully openEnsure the boiler pressure is between 1 and 1.5 bar on the pressure gaugeCheck if the pump is running or if there are any obvious signs of a leak
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 212 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Worcester Bosch GB162 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.