I recently purchased a home and once utilities were turned on I've been having issues with certain gas appliances. Some appliances required a normal amount of time to get the gas flowing after being off for some time. One water heater was finally able to light, as well as one furnace and the stove. However, a second water heater, second furnace, and the gas-log fireplace will not light. The individual gas valves to each appliance are in the on position but I never smell any gas. Is it possible for there to be restrictions in the gas supply lines that would affect all of these appliances? How can I troubleshoot this issue?
It sounds like the gas system was never purged after a nitrogen test. The appliances in question are probably farther down the line and still have non-combustables in them. It will take a very long time to purge through a pilot tube. You need to close the gas line valve on one of the appliances, remove the drip leg, open the valve to vent non-combustables and close it when the sound changes or you smell gas. Replace the drip leg, open the valve and start the appliance.
Do not do this alone. Someone needs to be with you in case you pass out, have a stroke, faint etc. It's very unlikely but if you are rendered incapable of closing the valve a second person can. This is important. Explosions happen because of this.