I replaced my gas oven thermostat yesterday. The job was easier than I
thought it would be and I have some questions after the fact.
1)After turning off the gas and unplugging the electric cord,
I took off the knobs and front of the oven to expose the old
thermostat. I simply unscrewed the 2 nuts that attached the
2 lines into the thermostat and removed the old thermostat, put
the new thermostat into place and reattached the 2 lines. I than
put everything back together. My questions a

The new thermostat came with 2 new nuts but I simply
used the old nuts that were already attached to the
existing lines. I didn't know if a special tool was
required to crimp the nuts to the lines and they
appeared to be secure. Is that ok? And

What are the 2 different lines leading into the thermostat?
I'm just curious why there are 2 lines, one larger than the
other.

Any response to my questions would be greatly appreciated so that I
can put my mind at ease that my house won't blow up from a gas
explosion.