Gas Fired Heating Systems:
Check for a gas shutoff valve within six feet of the burner. This is needed to safely shut off the fuel. There must have approved black iron gas piping for the supply lines. No copper or other materials should be used that aren't approved to carry gas fuel.
Check for the proper color of the burner flames. They should be as blue as possible with very little yellow or orange color. Too much yellow or orange color means that the fuel and air mixture needs to be adjusted. There's very little maintenance with a gas system. You just need to have the flame adjusted when it's not blue and clean out the flue pipe periodically.
There should be a thermocouple in the gas burner assembly for safety. It looks like a thin metal wire, leading to a cone shaped metal part inside the burner area, next to the pilot light. The purpose of this is to make sure that the pilot light is always lit when gas is supplied to the unit. This will help prevent gas leaking from an unlit pilot opening. When the pilot light is burning it heats up the thermocouple cone and sends an electrical current through the thermocouple to the gas burner assembly. The electrical current keeps the gas valve open. If the pilot light goes out, then the thermocouple will cool. If this happens, the electrical current will cease to the gas assembly. This should close off the gas from entering the pilot light burner jet.
Check the draft diverter hood at the base of the flue pipe. This has a very similar purpose as the oil fired draft regulator door. The draft diverter hood is used to keep downdrafts from the chimney from blowing out the pilot light. It's also designed to help keep the heat inside the boiler or furnace while the carbon monoxide is removed up the chimney. This does not need to be adjusted every year like a draft regulator door. There are no moving parts on it. It's just an opening at the base of the flue stack.