Your boiler has been manually switched to a mode where it only provides hot water and has turned the central heating off for the season.
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.
Technical description: Manual summer/winter changeover
What causes this fault?
This code appears when the boiler's control settings have been intentionally adjusted to turn off the central heating while keeping the hot water active. It is triggered by a manual user selection on the control panel, often done to save energy when heating isn't needed. There is no mechanical failure; the boiler is simply following a command to operate in 'hot water only' mode.
This code is most frequently seen during the spring and summer months when homeowners manually switch over to summer mode.
DIY fix possible
Locate the control panel on the front of the boilerAccess the menu settings to find 'Heating and Hot Water' modeSwitch the setting from 'Summer mode' back to 'Heating and Hot Water' to re-enable your radiators
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 81:0 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.