My boiler isn't working and there's an error code or flashing light
Have a look at the display on the front of your boiler. Boilers will usually flash an error code if there is a problem. Some boilers may not have a digital display but may still have flashing lights to indicate a fault.
If there is an issue with the power supply, there may be nothing on the display.
The error code may look like a red light where E1 is displayed, shortly followed by 19. E1-19 signals low system pressure.
Different boilers have different error codes for common faults.
I've got a Baxi 105e/he
A red light flashing below number 30 on a Baxi 105e/he/ = Ignition fault or no gas. A red light flashing below number 60 on a Baxi 105e/he = Pump failure or air in the system. Check your boiler pressure gauge, if it's below 1 bar then select the low-pressure option.
What error code can you see?