Your boiler has detected that there isn't enough water pressure or the water isn't moving through the system properly to keep it running safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flashing lamp, alternate with another lamp.
What causes this fault?
This fault occurs when the boiler detects that water is either missing or not moving through the internal pipes quickly enough to safely carry heat away from the burner. The most common reasons are a loss of system pressure due to a leak, a pump that has seized up, or a heavy build-up of debris blocking the internal flow.
This issue often appears when the heating is first turned on after summer, as the internal pump can seize up if it hasn't been used for several months.
DIY fix possible
Check the pressure gauge on the front of the boiler; it should be between 1 and 1.5 bar.If the pressure is low, use the filling loop underneath the boiler to top it up with water.Ensure all radiator valves and lockdowns are open to allow water to flow through the system.
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 Faulty primary circuit (no water or absence of flow) — no call-out fees, no surprises.
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Ideal Mini HE 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.
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