BoilerFaultCodesYour boiler has been intentionally restricted by an installer to prevent the water from getting too hot, usually to protect your underfloor heating or plastic pipes.
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: Flow temperature is limited within Installer Mode.
What causes this fault?
This occurs when an installer has manually programmed a maximum temperature limit into the boiler's software to protect your home's pipework or underfloor heating systems. It is a safety feature that prevents the water from reaching 80ºC, even if you try to turn the thermostat up higher. The message appears simply to inform you that the physical hardware is capable of more heat, but the software is intentionally holding it back.
This is often noticed during the first cold snap of winter when homeowners try to increase their radiator temperatures to combat the freezing outdoor conditions.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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 FLOW TEMPERATURE SETPOINT CANNOT BE INCREASED TO 80ºC — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.