Performed maintenance on x1 Gas Boiler. Inspect heat exchanger for cracks or deterioration. Clean burner tubes and cabinet. Inspect and test pilot and pilot assembly. Check safety controls. Check expansion tank, water feeder and relief valve. Check Aquastat relay and zone valve. Isolate and ran zoning operation. Check thermostat operation. Ran and check heating operation to be well @ this time. Maintenance completed no issues @ this time. Advised customer about age of boiler and boiler life expectancy that system could fail due to age of equipment and customer should consider replacement options for the future.