Having problems with the 3-wire pilot light on my carrier furnace. It started acting up the first time I turned it on this year. Pilot would light, igniter would still be going and the burners would never fire up. Cleaned out the pilot assembly and would still not work.
I unplugged the pilot while it was lit and jumped the white and yellow terminals, burners light and furnace works fine. I figured that the pilot assembly was not working so I replaced it. With the new one in, the first time I fired it up everything worked except the main burners would go out then back on every couple of seconds. But it did take a couple of minutes from the time the pilot lit till the burners kicked on. I shut off the furnace and later when I turned it back on, the original problem happened. Pilot lights, igniter stays on and no burners. Any ideas on what is happening. Thanks
U may have a bad out of box 3 wire pilot or a ground problem. You also may have a crack in heat exchanger that blowing back into it. I had found that couple time but also found had pilot out of the box too.