Arrived on site for a no heat. We met clients son on site and because homeowner was unavailable. We found the filter was so heavily impacted it was tripping the limit switch. Gas pressure and fan speeds were appropriate. Duct work is old, hard piped and dirty causing rapid filter decline. The Uv bulb had a blown fuse and the ballast was failed. We recommend new UV protection on the supply side and more regular filter changes. Condensate tubing was collapsing, and the outdoor unit was extremely dirty as well. We recommended Homecare to continue Maintenace and to avoid these kinds of failures but due to client not being home and the individuals on site being busy, closeout was rapid and I was unable to fully discuss all options today. System is fully operational now that we have new filter but Maintenace is highly recommended. All recommended improvements are emailed via estimates. Call complete.