What is the difference between a gas safety check & a service ? April 14, 2019 A gas safety check assesses the basic safety of gas appliances in your home to ensure they are all working correctly and safely. A Gas Safe registered engineer will assess the following four areas:Gas appliances are on the right setting and burning correctly with the correct operating pressureHarmful gases are being removed from the appliance safely to the air outsideThat any ventilation routes are clear and adequateAll the safety devices are working properlyA service will consist of a full check of a gas appliance and - in addition to the above checks - the registered engineer will dismantle the appliance to inspect and clean it. The engineer will assess the physical condition of the appliance, installation pipework, air vents and any flues for deterioration. They will carry out performance tests to ensure the appliance is operating safely and efficiently and take any necessary remedial action, alerting you to any issues.