Main 1 flash red Fault Code

Also written as 1FLASHRED — same fault.

The Main 1 flash red fault code means: your boiler has lost the ability to accurately measure the temperature of the water circulating inside it, so it has shut down as a precaution to prevent damage.. It appears on 1 Main model in our database.

Technical description: Sensor error (Bad connection to flow or return temperature sensor, Fault with flow or return temperature sensor(s), Low or no flow through boiler, Reverse flow through boiler)