Gas Hot Water Boiler.35 years old. Perform a tune-up and cleaning to help ensure reliable and safe operation. Inspect for cracks & deterioration of Heat Exchanger. Check and clean Burners, brush and vacuumed-ok Check and clean thermocouple and pilot Assembly-ok Check Safety Controls-ok Check electrical wiring and components-ok Check GVD-Damper-N/A Check water feeder-ok Check back flow prevent-ok Check expansion tank-okay Check relive valve-ok Check Gas valve & Gas Line-ok Check Combustion Air, Flue pipe-ok Check Temperatures & Water pressure settings; Performance-ok Check and run Thermostats-okay Check circulation pumps-ok Inspected water heater.20 years old unit. Check for water leak-no leakage at this time. Check gas valve and gas Line-ok Check and flush water tank un till water comes clear-okay Water condition- a little bit rusty. Ran water heater, operating at this moment. Run system, check water lines all of them getting hot, left system operating well at this moment. -/-/-/-