Meridian Furnace 26063 #63 Piston. Meridians goal is to provide contractors with high-quality HVAC solutions and replacement parts. This system includes changes and inventory updates to ensure peak performance. Meridian has a large line up parts and products for high-efficiency packaged rooftop units, split systems, HVAC controls, furnaces and indoor air quality products. This Meridian Furnace 26063 #63 Piston is designed for an outdoor Air Conditioning Unit.