Commercial Refrigeration Glossary
Commercial refrigeration guides for Bay Area businesses
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Updated October 14, 2026
Quick answer
These are the terms a technician is likely to use when explaining a walk-in, reach-in, ice machine or draft system repair, in plain English.
Terms A to Z
| Term | What it means |
|---|---|
| A2L refrigerant | A mildly flammable refrigerant class (for example R-454C and R-455A) used in some newer commercial systems. |
| AWEF | Annual Walk-in Energy Factor, DOE's efficiency metric for walk-in refrigeration systems. |
| Bin control | The sensor or switch that stops an ice machine when the bin is full. A dirty or misaligned one stops ice production early or lets the bin overflow. |
| Compressor | The pump that moves refrigerant and raises its pressure. When it fails, the system cannot remove heat. |
| Condenser | The coil that releases heat outside the box. A dirty condenser makes the system run hot and long. |
| Condensing unit | The outdoor or rooftop assembly holding the compressor, condenser and fan on a remote walk-in. |
| Defrost cycle | A timed or demand period when a freezer or low-temperature evaporator melts its frost, using heaters, hot gas or simply the off cycle. |
| Defrost termination | The sensor or switch that ends defrost once the coil is clear. If it fails, coils ice up or defrost runs too long. |
| Door heater (heater wire) | A low-wattage heater in a freezer door frame that stops the gasket from freezing to the frame. |
| Evaporator (unit cooler) | The coil and fans inside the box that absorb heat from the air. |
| Evaporator fan motor | The motor that moves air over the evaporator. If it stops, the box warms even with the compressor running. |
| Flaker | An ice machine that makes flake or nugget ice continuously with an auger inside a freezing cylinder. |
| Gasket | The rubber seal around a door. A torn or flattened gasket lets warm, wet air in and causes frost and sweating. |
| Glycol power pack | The chiller that pumps cold glycol alongside long-draw beer lines to keep beer cold from keg to tap. |
| GWP | Global warming potential, used by EPA to set refrigerant limits for new equipment. |
| Harvest | The part of a cube ice machine's cycle when finished ice is released into the bin. |
| Head pressure | The high-side pressure of a refrigeration system. It rises with a dirty condenser or hot surroundings. |
| Pressure relief port | A vent in a walk-in freezer wall that equalizes pressure so the door can be opened after it closes. |
| R-290 | Propane used as a refrigerant. Common in new self-contained units; flammable, so service needs trained technicians. |
| R-404A | A high-GWP refrigerant common in older walk-ins and reach-ins. Existing systems can still be repaired. |
| Remote system | A system whose condensing unit sits away from the box, connected by refrigerant lines. |
| Scale | Mineral deposits from hard water that coat ice machine evaporators and augers and slow production. |
| Self-contained unit | Equipment with the whole refrigeration system built into the cabinet, such as reach-ins and prep tables. |
| Short cycling | A compressor turning on and off too often. It wears parts and usually points to a control, airflow or charge problem. |
| Strip curtain | Overlapping plastic strips in a walk-in doorway that cut warm-air infiltration when the door is open. |
| Subcooling and superheat | Technician measurements that show whether the refrigerant charge and metering device are working correctly. |
| TXV | Thermostatic expansion valve, which meters refrigerant into the evaporator. |
When to call a technician
If a cooler, freezer or ice machine still is not right after the safe checks, a C-38 refrigeration technician can find the cause.
Open 7 days, 8 AM to 5 PM, with emergency service until 9 PM. CA Lic. #776244.
Frequently asked questions
What is the difference between a condenser and a condensing unit?
The condenser is the coil that releases heat. A condensing unit is the whole outdoor assembly: compressor, condenser and fan.
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