the inner core should be cleaned and lubricated after each use

The Nor East Controls 30048918-859 Bonnet Gasket is a critical sealing component engineered for high-performance pressure containment in industrial and mechanical valve assemblies

Technical Precision: Includes 1/8" NPT pressure taps for easy verification of natural gas settings during annual maintenance or troubleshooting

and 1178420

Amana-Goodman DFK-C Kit L99H008 the inner core should beThe Amana Goodman DFK C Kit is a critical OEM Downflow Conversion Kit engineered for 21 inch "C" chassis air handlers. This professional grade HVAC furnace accessory allows for the seamless transition of upflow units into a downflow configuration, essential for specific residential and commercial architectural requirements. By applying high quality insulation to the bottom of the drain pan, the DFK C kit prevents "sweating" and condensation buildup,