Checked in with Customers. Cleaned out control cabinet. Cleaned off flame sensor electrode. Inspected Hot Surface Igniter . Removed and cleaned burners. checked natural gas outlet pressure ( 3.4 inw.c.) Pulled amp draws on all mechanical components. Inspected bulkhead and heat exchanger. Pulled temperature rise 77° return 127°supply = 50° TR . The unit is operating at factory recommended specifications at this time. Job Complete