I have a payne hvac system. Until about 2 weeks ago, it ran perfect. At that time it was cleaned, the a-coil, blower wheel, return duct etc.
Now when the furnace is in use, it runs about 2 minutes, the flame goes out, the blower runs another minute and a half. After it shuts off, the furnace fan motor continues to run. The furnace re-ignites, the fan motor starts, blowing, then the process starts all over. This continues until it reaches the thermostat set point or you get tired of hearing the thing and lower the thermostat setting.
I think it is a limit switch. How do you test them without replacing them, in a trial and error process.
Any suggestions would be helpful!

It could be some kind of blockage in the supply or return duct. It could be a limit switch as you said. If you have the meters and the tools you can check the limit for continuity when the unit shuts down. Careful you are playing with electric.

i have a payne hvac system. until about 2 weeks ago, it ran perfect. at that time it was cleaned, the a-coil, blower wheel, return duct etc.
now when the furnace is in use, it runs about 2 minutes, the flame goes out, the blower runs another minute and a half. after it shuts off, the furnace fan motor continues to run. the furnace re-ignites, the fan motor starts, blowing, then the process starts all over. this continues until it reaches the thermostat set point or you get tired of hearing the thing and lower the thermostat setting.
I think it is a limit switch. How do you test them without replacing them, in a trial and error process.
Any suggestions would be helpful!
I did check each one for continuity, and it turned out to be the limit switch. Which is in the combustion chamber, it is the only auto reset limit switch, out of four total. I jumped it, and it has ran perfect, last night and this morning. I will get a new switch early next week.
Thanks