Performed heat maintenance on two Armstrong air 2017 single stage furnaces. Clean flame sensors. Removed the dirty air filters and gave homeowner the size so he can install some new 4” filters asap. Checked coils, no leaks. 8 degree subcool. Made recommendations for condenser repairs and float switch install. Did the start assist kits today, as well as the upstairs capacitor. Will do float switch later this year. Systems heating and cooling properly.