I have an n8mpn gas furnace. It will completely shut off. There is no power going to the circuit board. We had a service tech to come out and check it. He diagnosed it as being the safety switch for the door access. He made a jumper for it to bypass the safety switch. That was Friday and by Sunday it did it again. It will work when we turn it back on but continues to cut off. Any suggestions on what is wrong and how to fix it?

Thanks
Kevin

It sounds like the high limit switch is kicking it off due to poor air flow, dirty coils and blower, or dirty filter.

Hi is the jumper that the tech put in still intact. when the furnace goes off were does the power stop at board, door switch,on off switch on furnace or breaker.

It does not seem that an open door safety would do this, but anything is possible. The fan/limit switch is usually in a rectangular box attached to the heat exchanger. To test it wait until it kicks off and read between the two terminals on the limit side (usually the right side). If you get voltage it's open and that's what is tripped. I don't understand why the technician did not fix the problem. Something does not sound right about this. I don't believe he knew what he was supposed to do because it should be a very simple problem and fix, but it's hard to get good technicians today.

Can someone help me to light the pilot light on my comfortmaker furnace? I do not know how and it seems to be a little different from those I pulled up on YouTube. This one has the red button of course, the knob for pilot, on and off. Below that there are 2 pipe like things that are facing two holes where there should be flames once lit. On the wall, there are two switches like light switches for power I am assuming. I have turned the pipe valve to perpendicular position (off) until I get it lit again. Do I need to use an external flame or is it electric/automatic.. I don't know, I need some help, please anyone that knows this type of heater.
Thank you.
Floyd
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Sooner the better, it is cold!

Try turning it to pilot and pressing red button and then lighting it. If it has no "pilot" position on valve, just "on" and "off" then all you need to do is to turn it to "on" and set it to call for heat and it will light automatically. If it has a flame rod to prove flame then it may need cleaning with some very fine sandpaper.