High
2965 on Worcester Bosch Greenstar 8000 Style System

Your boiler has sensed that the water inside is getting much hotter than it should be and has shut down as a safety precaution.

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.

What the manual says

Manufacturer manual

Flow temperature too high

From this model's manual
Verified against the Worcester Bosch Greenstar 8000 Life Style installation & service manual, page 80.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the water leaving the boiler exceeds its safe temperature limit, causing the system to shut down to prevent damage. The most common reason is a lack of water flow, often caused by a failing internal pump or a blockage in the pipes that stops heat from being carried away from the burner. It can also happen if a sensor fails and incorrectly reports that the water is overheating.

This fault is more frequent during the first cold spell of autumn when heating systems are turned on after months of inactivity, which can cause internal pumps to seize.

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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