Gas fires, sometimes when I turn on the appliance for the first time I get an error code 11 or 12 appear on the PCB

Error code 11 indicates that the flame sensing device has not registered that a flame is present on the burner. This can be caused by the gas not having been connected or turned on or that there is excessive air in the pipe that needs to be purged through the pilot injector. The pilot injector especially on LPG appliances is very small and can take many attempts, be patient and go through the ignition cycle at least 10 to 15 times before you think there is a problem.

Error code 12 indicates either that a flame has been present but has gone out or that in most of our appliances that have two flame sensing rods that the first one has sensed but the second one hasn’t.