Refurbished vs Used Ammonia Compressors: What to Inspect

“Refurbished Grasso compressors” and “used ammonia refrigeration plant” are already sending impressions here. Buyers want capacity without new-package lead time. Sellers want the word refurbished on a machine that was only washed. The difference is a clearance sheet.

Used means it ran, it was cleaned, and someone looked at it. That can be honest if hours, last duty, and oil condition are known. It is a gamble if the nameplate is painted over and the shaft turns “freely” because the bearings are loose.

Refurbished should mean a stated list: seals, bearings, gaskets, and any measured wear parts. Remanufactured should mean a full strip, recorded clearances, and a test run where the frame allows it. Ask which word they are using. If they cannot list the parts, they are selling used.

Inspect before paint. Housing cracks, shaft pits, mounting-foot repairs, and rotor thrust smear hide under enamel. On pistons, ask for liner ovality and crank-journal numbers. On screws, ask for bearing play and lobe condition. A photo of a shiny unit is not a report.

A complete used plant is a different buy. Vessels, evaporators, and detection may be the expensive part. Moving a tired compressor with a tired vessel is how a bargain becomes two projects. We often recommend a remanufactured compressor into vessels that still pass inspection — or a turnkey install with only the coils you keep.

Installation after sale is not optional. Oil charge, alignment, leak test, and staged load-up decide whether the machine survives the first week. A used compressor dropped on a soft pad with the old coupling offset will weep a new seal immediately.

If you are covering a shutdown, say so. A workshop-overhauled spare while your serial number is on the bench is the cleanest version of “refurbished.” If you are building a room, say the duty. We will not match a high-stage screw to a blast-freezer suction from a listing title.