Oil-fired combustion appliances are also relatively safe to inspect. Furnaces and boilers are the most common. The main concern to inspector safety is from fire. If the burner fails to ignite the heating oil when the thermostat calls for heat, the system will automatically shut down. A reset button must be activated before another attempt can be made to operate the system. With each activation of the reset button, more heating oil is pumped into the burner. If a significant amount of heating oil accumulates in the burner due to repeated unsuccessful attempts, when the burner finally ignites, a fire can result. Heating oil fires can be difficult to extinguish.
A number of failed attempts followed by a successful ignition is not unusual in systems needing service. If an oil-fired combustion appliance fails to respond to the call for heat, the inspector should not reset the system but should note in the report that the system failed to respond, recommend service by a qualified HVAC contractor, and move on with the inspection.