What changes between products?
A packaging hall that only needs a refrigerated dew point and a paint booth that needs a desiccant dew point are not interchangeable inquiries. Throughput here is peak moisture load at the hottest credible inlet and ambient temperatures, not nameplate scfm copied from a compressor tag. Ask each bidder to show the rating basis and the correction applied to your conditions.
What must be cleaned or replaced?
Tower desiccant, coalescing elements and drain valves change more often than the pressure vessel. If the purchase replaces an existing skid, list which housings stay and which must ship with the new dryer. Filter and dryer pressure losses in a specified dirty condition belong on that same list so the plant compressor still meets working pressure at the tools.
How is the first good output verified?
Owner acceptance should record dew point at peak demand, drain function and whether purge air or regeneration energy was included in the operating figures used for the SAT. A stable reading during light demand does not demonstrate that the dryer meets the plant’s peak moisture load.