Low
208 on Worcester Bosch Greenstar 8000 Style System

Your boiler is currently set to a manual testing mode used by engineers to check emissions, which prevents it from operating normally.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

What the manual says

Manufacturer manual

Chimney sweep demand

From this model's manual
Verified against the Worcester Bosch Greenstar 8000 Life Style installation & service manual, page 75.
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 code appears when the 'Chimney Sweep' mode has been manually activated on the boiler's control panel. It is a setting used by engineers during a service to force the boiler into maximum or minimum output for emissions testing, which overrides your normal heating and hot water settings. If this has appeared unexpectedly, it is usually because the button was pressed by accident or the mode was not exited after a recent service.

This code is frequently seen during the autumn and winter months when annual service visits and safety checks are most commonly scheduled.

DIY fix possible

Locate the 'Chimney Sweep' button (icon looks like a brush) on the touch screen display.Press and hold the button for approximately 3 to 5 seconds.The display should return to the standard temperature screen once the mode is deactivated.

Find a Gas Safe engineer
Search the official register →

Avoid the next call-out bill

Monthly cover means no unexpected bills when your boiler breaks down.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.

Related fault codes

Related guides you might find useful