A pro pool tech inspecting a pool heater after installation methodically checks each component and system to ensure safe, efficient operation: they verify proper gas or electrical connections, confirm correct venting and clearances, inspect piping and unions for leaks, and test the thermostat and control settings for accurate temperature regulation. The technician runs the heater through a startup sequence, monitoring flame pattern or ignition, water flow and pressure, and combustion exhaust for signs of incomplete combustion or blockages. They review error codes, validate that safety devices such as pressure switches and high-limit sensors function, and measure temperature rise across the heat exchanger to confirm manufacturer specifications. Finally, the tech documents readings, makes any necessary adjustments, explains operating and maintenance needs to the owner, and leaves a checklist and recommendations to ensure long-term reliability and warranty compliance.