My Ruud sillouhette II furnace is not firing up. I can hear a very faint hum, but the igniter does not get hot. I opened the bottom cover and i see two green lights on a circuit board. They are illuminated and there is a yellow light next to them that is not illuminated. Are these error codes. If so what do they mean. Where can I get a reference for the codes? Thanks Dave "very cold" Nathan.