Gas technicians service and maintain residential and commercial gas appliances and systems. They repair any issues they encounter, such as gas leaks or other problems related to gas pumps, pipes, or systems, and accurately document all the repairs. A gas technician tests safety devices, checks for gas leaks, and inspects and fixes a variety of appliances, such as ovens, water heaters, boilers and furnaces, and central heating systems. Some technicians also assist in the installation of new gas lines.