Preform maintenance on gas fired water boiler with (3) heating zones: * shut power to boiler * Shut pilot off at gas valve * Removed flame, guard, and rollout switch * Removed all burner tubes and pilot assembly from boiler and gas valve * Inspected heat, exchanger and flu piping * Vacuum and dusted out burner section under heat exchanger * Vacuum and dusted boiler cabinet and components, clean and clear * Vacuum and dusted boiler, piping and components, clean and clear * brushed out and vacuumed all burner tubes, clean and clear * Recommend thermocouple replacement- Customer approved * removed existing thermocouple- preform full maintenance on pilot assembly * installed brand new thermocouple securing in gas valve and pilot assembly- Check for leaks- None * Reinstalled all burner tubes, flame, guard, and rollout switch * Secured and inspected all electrical wiring, and components and polished clean * Test and inspect system expansion tank, Water feed and backflow preventer, Air vent