Installing a heating system is not the easiest thing in the world to do. There are many parts that have to be properly installed for the unit to function properly. With this is the matter of safety that must be thought about. Installing a gas heating system means that everything needs to be done a certain way and in many cases in a certain order.
There is nothing that one should try to go around or take a shortcut on. An improperly installed gas heating system can be very dangerous to the residents.
First off you need to set aside the proper amount of space for the heating system. If this unit is a furnace that will used forced air then it must be placed in an area of the home where there is substantial venting room through the roof of the home. Most often you will find that a forced air furnace is placed in the basement where there is more than enough room for the unit to breath. If this is not possible then you should choose a place where there is enough room for the unit so that it will be out of the way. A large storage closet that is centrally placed is usual and can provide the installer with more than enough access to the roof for venting procedures.
Running the gas line is also important. Wherever the gas line comes into the house you need to take a splice in from the main pipe. In a home with a basement this will be somewhere in that area, normally near a small window. With the main pipe line coming in you will need to shut off the main supply to the home.
This is done at the meter and a lock should be placed on the meter to ensure that no one turns the gas on again during the whole process. Cut the line and splice in a three way tee. This will give you the ports that you need to run to the new heating system and then back to where the main line was running.
Once you have the gas line installed you will need to run it to the appliance and then hook up the electricity. Most often a forced air heating system will require 220 volts of power, so they need to be running off of a double breaker rather than a single unit. Check all connections, including the gas fittings before you start the power.