Hey, thanks to anyone who can help me with this in advance. My furnace won't ignite, and I have flipped the external valve to OFF and left it for long periods of time with the temp all the way down and then turned it back to ON and turned the temp up but this is not working. It has worked in the past (the last couple months this has happened a few times) but this time it is not working. I am pretty clueless when it comes to these kinds of things. Any ideas?