Gas Furnace burner shuts off after a minute even with new sensor

BE AWARE THAT MAGIC CHEF IS NO LONGER IN BUSINESS!
In my experience a 20 year old Magic Chef probably has a bad heat exchanger which can cause carbon monoxide poisoning and can not be replaced since Magic Chef is not around any more!
Today’s furnaces are controlled by a computer which constantly monitors for problems. When it detects a problem it will shut off the burners. Depending on the problem and the specific furnace it will either “lock out” the furnace or cycle it through a purge (to rid it of un-burned gas and excess heat) and then attempt to re-start it. If the problem continues to occur then it will “lock out”. Depending on the problem and the furnace it may again attempt a re-start after several hours. In any case if the problem was not detected/caused by a sensor which requires a manual re-set, when the power to the computer is interrupted or the call for heat is interrupted the computer is reset and it will again attempt to re-start the furnace. The most common problems are:
· Low or lack of flame sense. Different furnaces use different methods to detect a flame – often these “flame sensors” become dirty and have to be cleaned (usually with sandpaper or steel wool).
· Bad igniter. (Doesn’t light at all).
· Clogged combustion air intake or exhaust.
· Clogged condensate drain. (90+% efficient furnaces).
This is not a complete list, only the most common!
Depending on where you live your HVAC system runs more than anything else you own (including your car). All furnace manufacturers “recommend” “regular maintenance” of your furnace. In fact, all that I am aware of state in their warranty that the warranty may be voided due to lack of “regular maintenance.” The industry has defined “regular maintenance” as yearly (in fact, some manufacturer’s warranties state yearly). Due to safety, liability, and the need for many other things to be checked, cleaned, and/or adjusted (2-page checklist where I work) to ensure safety and efficiency. Due to the large number of furnaces and the differences between them. Moreover, due to the terms of this site, I WILL NOT AND CAN NOT give you specific instructions on how to perform repairs on your furnace. I suggest that you contact a local, reputable, HVAC service company for (a tune up, preventive maintenance, general maintenance, yearly service call, general service, or whatever they call it).

While I may not have told you how to fix your furnace yourself, I have told you how to fix it. Please rate my answer.