BoilerFaultCodesYour boiler has sensed that water is not circulating properly before it starts the heating process, which is usually caused by an air lock or a blockage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Pre-Circulation Fault
What causes this fault?
This fault occurs when the boiler's internal sensors detect that water isn't moving through the unit quickly enough during its initial checks. This is usually caused by a large pocket of air trapped inside the pipework or a failing pump that no longer has the power to push water around the system. In some cases, a build-up of sludge or debris can also create a physical blockage that restricts the flow.
This issue is more frequent in autumn when the heating is turned back on after a long summer break, as pumps can seize and air can settle in the pipes during periods of inactivity.
DIY fix possible
Check that your system pressure is between 1 and 1.5 bar on the pressure gaugeEnsure all radiator valves and isolation valves under the boiler are fully openGently bleed your radiators to remove any trapped air
Find a Gas Safe engineer
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A boiler cover plan would cover faults like E193 — no call-out fees, no surprises.
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