Performed annual heating maintenance, 26 yr old split goodman system attic backyard. Filter 20-30-1. Changed filter for client. System operational at this time. Checked system, system has new primary control board. Cycled system on and turns right on. Blower capacitor 12.5. Hot surface ignitor ok. Gas line into system is missing a drip leg. It wasn’t code when system was installed 26 yrs ago. System is working for now. All parts in range. Unit is just getting to the end of its life. And newer units are more efficient. Black flex ducts attic return seems a little tight around rafters. Cleaned off exterior of unit.