Why is it that.....

[Vulcan Bob]

Things that you cannot repair yourself always go belly up over the weekend? Got up this morning grabbed some coffee and noticed the furnace (natural gas) sounded like it was in the fire up stage but did not complete the cycle for a much longer time than normal. Turns out the exhaust system (turns on first) will not turn off and runs continually. Did the normal shut it down and turn it on thing,did the wiggle and jiggle tests and checked the water trap and drain with no joy. With all the electronic controlls on this thing Im lost. Oh well at least the furnace will work this way and we will not freeze and gave the service guy a call for help.

 

[kamloops67]

i know what you mean.
my vehicles will run flawlessly through summer and fall, then when there is snow on the ground and the garage is colder inside that out ,things start to come apart. most recently an electrical short in the blower fan, now my windshield wont defrost until i have driven 6-7 miles... i live about 6-7 miles from

 

[BruceB]

Things that you cannot repair yourself always go belly up over the weekend? Got up this morning grabbed some coffee and noticed the furnace (natural gas) sounded like it was in the fire up stage but did not complete the cycle for a much longer time than normal. Turns out the exhaust system (turns on first) will not turn off and runs continually. Did the normal shut it down and turn it on thing,did the wiggle and jiggle tests and checked the water trap and drain with no joy. With all the electronic controlls on this thing Im lost. Oh well at least the furnace will work this way and we will not freeze and gave the service guy a call for help.

I had the similar symptoms at my last house with a horizontal gas furnace in the crawl space. The blinking light error decoder on the controller kept giving different results.

I finally got my trouble-shooting head on straight, realized that ALL those sensors didn't go bad at once, and re-seated the big connector to the control board. That fixed it right up. It did the same thing a half a dozen more times, so it became fall ritual to re-seat the connector.