Twenty minutes standing in front of a machine will not tell you whether a compressor bearing fails eight months from now. Nothing will. What it will tell you is whether the obvious problems are present: a compressor that clicks, coils packed with lint, a gasket that no longer seals, a slicer with a dead blade.
Those are the findings that move the price, and most of them are visible to anyone who knows the order to look in. Here is the order.
Before you leave: the two checks that happen first
Do these from your phone, before you drive anywhere, because they can end the conversation.
Get the model and serial number from the seller. Not the model alone. Both. If a seller will not send a photo of the data plate, you have learned what you needed to learn.
Run the model against the two live fire recalls in this category. True commercial refrigerators built January 2018 to June 2020 with Secop NLE11MN compressors are under CPSC recall 24-219, fifteen models, fourteen reported fires, free repair from True. Scotsman ice machines across fourteen model numbers with serials starting 05 through 09 are under CPSC recall 10-147, four fires and 37 burned or melted components, free repair from Scotsman.
Everything else in this checklist is about money. These two are about fire. Ninety seconds, up front.
What to bring
A flashlight. A thermometer. A dollar bill. Something to slice if you are looking at a slicer or a cutter. Your phone, for the data plate photo and the model record.
And three questions for the seller, asked early: when were the condenser coils last cleaned, why are you selling it, and can I run it. The coil question is the one that matters most and we will get to why. The other two are for watching the answer arrive, not for the answer itself.
Minutes 1 to 3: the walk-around
- Find the data plate and photograph it. Model, serial, voltage, phase, and on refrigeration, the refrigerant type. That last one is not trivia: units built after roughly 2017 increasingly use R290 hydrocarbon refrigerant, and servicing R290 requires an R290-certified technician. Confirm the refrigerant era before you budget any repair.
- Look at the condenser coils. This is the single highest-value ten seconds of the entire inspection. Coils choked with dust and grease are the documented number one killer of commercial refrigeration. Parts Town's own troubleshooting guidance is blunt about it: continuous operation with a dirty or clogged coil can cause compressor failure, and neglected coil cleaning voids compressor warranty coverage outright. Dirty coils do not mean the machine is dead. They mean nobody maintained it, and the compressor has been paying for that.
- Check for oil residue around the compressor. Forget trying to smell a refrigerant leak. The documented tell is oil residue on the compressor combined with excessive heat. Refrigerant carries oil, so where refrigerant has been leaking, oil stains follow. Dark wet residue around seams and fittings is the thing to look for.
- Work the doors. Hinges that have loosened or sagged under heavy use can pull out of the frame and damage both the door and the hinge. Open and close each door fully. Sag and misalignment are visible in one pass.
- Look at the installed clearance. If the unit has been wedged into a spot with no air gap around it, that is an installation error that causes refrigeration problems without any defect in the machine. It also tells you how the previous owner thought about equipment.
Minutes 4 to 6: power on and listen
Ask before you plug anything in. Then say nothing for fifteen seconds and listen.
- Listen for clicking from the compressor. This is the most useful single sound in used refrigeration. Repair-forum guidance for the True GDM-49 line puts an audible clicking compressor at roughly an 80 percent chance the compressor is dead. Treat that as strong field guidance rather than a laboratory figure, but treat it seriously: clicking usually means the motor is trying to start and failing.
- A compressor that will not start at all has two commonly cited causes worth separating, because they cost very different amounts. Low supply voltage is an electrician-level problem with the building, not the machine. A defective start relay is a technician-level part swap. Neither one is automatically a dead compressor, and a seller who has assumed the worst may have mispriced the unit in your favor.
- Grinding, rattling, or banging from a sealed compressor is internal and not economically repairable. That is a walk.
- Watch the cycling. Short-cycling, where the compressor kicks on and off repeatedly, is a recurring complaint pattern on prep tables like the TSSU-48-12, and it has a specific documented cause worth knowing: a temperature controller that has lost its range. The related failure is stuck-closed controller contacts, which do the opposite and keep the compressor running continuously. Both are controller replacements rather than compressor replacements, which is a much better outcome than it sounds like standing there.
Minutes 7 to 15: the hands-on tests
Let it run while you work through these.
- Feel the condenser airflow. After a few minutes of running, the condenser area should be moving warm air steadily. Room-temperature air off a running compressor means heat is not being rejected.
- Open it up and look for frost. Evaporator coil frost or ice buildup restricts airflow and points at an airflow or defrost fault, not just a cosmetic issue. On the TSSU line this shows up alongside a specific diagnostic: low-side pressure dropping below about 10 psi overnight, flagged as a sign of extended compressor run time, low load, or a defrost problem. You will not be gauging pressures at a seller's warehouse, but heavy frost tells you to ask whether anyone has.
- Test the gaskets with a dollar bill. Close the door on it and pull. Firm resistance means the gasket seals. If it slides out easily, the gasket is done. This is a genuine wear item and it has a real price: the True OEM gasket that fits the GDM-49 and T-49 lists at $126.02. Cheap as a part, expensive as a symptom, because a failed gasket means the compressor has been running overtime to hold temperature for however long it has been like that.
- Compare two thermometers. Put your thermometer inside, wait, and compare what it reads against what the unit's own controller displays. The gap between those two numbers is the tell. A controller reading correct while the box sits warm is a controller problem or an airflow problem, and it means the previous owner may not have known the machine was running warm.
- Check that it holds, not just that it pulls down. Anything with a working compressor can get cold once. Watch whether it stays there while the door gets opened.
If it is a slicer or a mixer
Different machine, different order.
- Find the overload reset before you conclude it is dead. Hobart's slicer troubleshooting guide lists a tripped overload, reset with a button underneath the unit, among the causes of a machine that will not start. So is a carriage that has not been returned to its home position. A "broken" slicer is sometimes neither.
- Slice something. The manufacturer's own guide states that a dull knife blade is the biggest culprit behind poorly sliced meat. Tugging and tearing is a blade problem first, before you go looking for anything expensive.
- Push the carriage through its full travel by hand. Binding points at worn transport bushings or a dry carriage slide rod.
- Check the sharpener for play in the mounting pins. Loose pins and worn stones are both named slice-quality causes. Stones are inexpensive. A full Hobart sharpener assembly is $534.55, so it matters which one you are looking at. Detail on both machines is in the slicer comparison.
What the findings are actually worth
The reason to inspect in this order is that one component dominates the economics of used refrigeration, and everything else is noise by comparison.
Compressor replacement runs roughly $1,000 installed as a working benchmark on common units. For a sense of the part alone: Delfield's R290 compressors for the 6051XL line list at $438.00 and $520.20 depending on the unit, and that is the part before any labor.
Put that against what these machines cost used. A clean reach-in trades in the $1,000 to $2,000 range. So on a $1,200 purchase, you are effectively betting the entire price of the machine on the health of one component. That is why the coil check comes second in this list and the gasket check comes later, even though the gasket is the more obvious defect. The coils tell you about the compressor. The gasket tells you about the coils.
Age sets the ceiling on all of it. Commercial refrigerators generally run 10 to 15 years, up to 20 with real maintenance. Ice machines run shorter: about 7 to 10 years typical, 12 to 15 with strong maintenance, closer to 5 if worked hard without service. And there is a specific threshold worth knowing on refrigeration: age-related compressor inefficiency gets flagged in field reports past roughly 15 years in service. A 16-year-old machine that runs today is not the same purchase as an 8-year-old machine that runs today, at any price.
Walk away on any of these
- Grinding, rattling, or banging from inside a sealed compressor.
- Clicking that does not resolve into a running compressor.
- Oil residue around the compressor plus a unit running hot.
- A model on either recall list, with a serial in range, and no repair documentation, where the seller will not let you arrange the free fix before taking possession.
- No serial number, no data plate, or a seller who will not photograph it.
- Fifteen-plus years old with no service history at anything other than scrap pricing.
Negotiate on these instead
- Dirty condenser coils. Not a defect by itself, but it is direct evidence of neglect, and neglect is what kills the compressor. Price it as risk, not as a cleaning bill.
- Failed door gasket. A real part at a known price, $126.02 on the True GDM-49 and T-49 line, plus what it implies about run time.
- Sagging door hinges. Fixable, and worth catching before they pull out of the frame and take the door with them.
- Short-cycling. If the cause is the temperature controller rather than the compressor, this is a far cheaper repair than it sounds. Worth investigating rather than walking on.
- Dull slicer blade or worn sharpener stones. The cheapest findings on this list and the easiest to point at while discussing price.
After the inspection
Take the model number to the model record before you pay. What you are looking for is not a verdict, it is three specifics: the observed used price range and how many comps it rests on, the documented failure modes for that exact machine, and the parts-catalog depth, because a discontinued model with a deep catalog is a value play and one with a thin catalog is a countdown timer.
Where we do not have a range, we say so rather than filling it in. That is more useful than a confident number, because it tells you that you are the one setting the price and should act accordingly. Browse by brand to find the record.