I have a 58rav115-16 caarrier unit. Lst week I replaced a suspected bad draft limit switch(code31) ran fine after. This morning I got up and the blower was running but it would not ignite. I switched to emergency heat and received a code31. I bypassed the draft switch and was able to get the them. Heat to cycle but, the reglar heat cylce still only the blower runs and the unit never ignites. Ay ideas?