My 7 yr old TRANE furnace is working intermittently. When the thermostat sends the signal for the heater to kick on, the flames start going without a problem, but after just 6-7 seconds, the flame disappears and the furnace tries to ignite again. Then after about the 3rd or 4th time, the fan kicks on and blow cold air until we manually turn off/on the thermostat at which then all is fine until the next episode. Never have an issue when we manually turn the heater on at thermostat, and only sometimes it happens(40%) when we leave it on auto. Any ideas/advice would be great!
I am experiencing a similar problem with my Lenox furnace (5 yrs old). It receives the signal to turn on and the fan begins circulation in the house but the flame only appears for approximately 5 seconds before going out again. Should I be looking for similar issues? I tried going through the trouble shooting section of the furnace manual but it makes very little sense.