heating and air conditioning systems

how to set fan and limit control for heating-air conditioning systems for residential systems?

I’m assuming you mean a standard dial type fan limit control. With the power in the off position, and holding the dial stationary, move the lower dial indicator to about 100 degrees and the higher number to about 150 degrees. The higher number is the temperature the fan will turn on and the lower number is the temp it turns off. Of course these settings can be changed for personal comfort, but these are a good start point. The other indicator should be permanently set at about 200 degrees and this is the temp the limit turns the furnace off due to over heating.

Air-conditioning systems