How the natural gas cock works

The gas cock is a manual valve placed in the gas line to shut off the gas supply if there is a problem with the gas appliance. I discuss how 3 different valves work and troubleshooting problems with them.
This video is part of the heating and cooling series of training videos made to accompany my websites: www.graycoolingman.com and www.grayfurnaceman.com to pass on what I have learned in many years of service and repair. If you have suggestions or comments they are welcome.
If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal, the fuels are highly flammable and high pressures are used. Know your limits.