High Lockout
2971 B on Worcester Bosch Greenstar 8000 Life/Style

Your boiler has detected that the water pressure in your heating system is too low to operate safely and effectively.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

System pressure too low – the heating system needs venting or water needs topping up until the preset pressure is reached. Replace the cable to the pressure sensor replace the pressure sensor

What causes this fault?

This fault occurs when the internal sensor detects that there is not enough water inside the system to safely transfer heat. The most common cause is a slow leak in the pipework or radiators, though it frequently happens after you have recently bled your radiators to remove air. In some cases, the error persists because the pressure sensor itself has failed or the electrical connection to it has become loose.

This code is frequently seen in autumn when homeowners turn their heating back on for the first time or bleed their radiators to prepare for winter.

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.

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