I have one of the newer ones with the front yellow colored. I have had the problem getting it to lite once it had some age to it. I can not see the original post to credit the author, but there is one, with pictures, that tells how to move the thermocouple from its original position up about a quarter of an inch. I did that and freakin’ magic, it works like a champ now. It is not a quick fix by any means however. The unit must be disassembled almost completely to get to the stupid mounting bracket for the thermocouple in order to move it. There are quite a few hidden screws to find during disassembly. But after finding them and getting over the frustration of reassembly it was well worth it.