Refrigerants
- R-22
- A hydrochlorofluorocarbon (HCFC) refrigerant phased out under the Montreal Protocol because it depletes the ozone layer. US production of R-22 ended on January 1, 2020. Existing R-22 systems can still operate, but any service call that requires a recharge depends on reclaimed R-22, which now runs $150–$300 per pound. For commercial refrigeration equipment older than 2010, any major refrigerant repair on an R-22 system typically costs more than 50% of replacement value — most operators replace rather than recharge.
- R-290 (Propane)
- A natural refrigerant — yes, the same propane used in gas grills — with GWP = 3 and excellent thermodynamic efficiency. Used in self-contained commercial refrigeration: reach-ins, prep tables, ice machines. Restricted to small charges (150 g maximum per circuit in the US) because of flammability. Manitowoc, Hoshizaki, True, and Hussmann all offer R-290 product lines.
- R-404A
- A hydrofluorocarbon (HFC) refrigerant blend that replaced R-22 in many commercial refrigeration applications in the 2000s. R-404A has a very high global warming potential (GWP = 3,922), so under the EPA SNAP rules and AIM Act it is being phased down through 2036. New equipment installed after 2025 typically uses lower-GWP alternatives like R-448A, R-449A, R-454C, or R-455A. Existing R-404A systems remain legal to service, but the refrigerant cost has tripled since 2020 as supply tightens.
- R-448A
- A lower-GWP HFC blend (GWP = 1,387) marketed by Honeywell as Solstice N40. R-448A is one of the most popular drop-in replacements for R-404A in supermarket refrigeration and walk-in coolers. It typically improves system efficiency by 5–10% over R-404A. Compatible with most existing equipment with minor modifications (TXV adjustment, sometimes new oil).
- R-449A
- Chemours' competing alternative to R-448A, sold as Opteon XP40. GWP = 1,397, very similar performance to R-448A. The choice between R-448A and R-449A is usually about service-truck inventory and contractor preference, not performance.
- R-454C
- A next-generation HFO/HFC blend with GWP = 148 — about a tenth of R-448A and a thirtieth of R-404A. Used in new commercial refrigeration equipment manufactured for the post-2025 SNAP-rule market. R-454C is mildly flammable (A2L classification), so it requires technicians trained in A2L handling and specific leak-detection equipment.
Components
- Capacitor
- A start-assist or run-capacity component on single-phase compressor and fan motors. Failed capacitors are the most common reason a compressor or fan "hums but doesn't start" — the motor is trying but can't generate enough starting torque. Capacitors are $15–$50 in parts and are a 10-minute replacement for any qualified tech.
- Compressor
- The pump at the heart of every refrigeration system, raising the pressure (and temperature) of low-pressure gas from the evaporator so it can reject heat at the condenser. Walk-in coolers use hermetic or semi-hermetic compressors; ice machines and reach-ins typically use hermetic. Compressor replacement is the single most expensive routine repair in commercial refrigeration — $1,800–$3,500 fully loaded — which is why keeping the condenser coil clean (the leading cause of premature compressor failure) is the highest-ROI maintenance habit.
- Condenser coil
- The outdoor heat exchanger where refrigerant rejects heat to ambient air. A condenser coated with 3 mm of grease (typical for restaurant kitchens) loses 40%+ of its heat-rejection capacity, forcing the compressor to work harder and run hotter. A clean condenser is the #1 preventive-maintenance task for commercial refrigeration. Twice-yearly cleaning extends compressor life by 3–5 years.
- Contactor
- An electromagnetic switch that turns the compressor and fans on/off in response to thermostat signals. Burned-out contactor points (visible as carbon arcing on the contact surfaces) are one of the most common electrical failures — symptoms include the compressor not starting at all, or starting intermittently. Replacement is $25–$80 in parts and a 30-minute tech job.
- Door gasket
- The rubber seal around a cooler or freezer door that prevents warm humid air from entering. Walk-in cooler gaskets last 3–5 years in heavy-use commercial kitchens before they need replacement. A failed gasket is the single most common cause of frost buildup on the evaporator coil. Test: close the door on a dollar bill — if you can pull it out without resistance, the gasket is gone. Replacement is $60–$200 in parts and most operators can DIY in 20 minutes.
- EPR (Evaporator Pressure Regulator)
- A back-pressure valve used in multi-evaporator systems (typically supermarket refrigeration with multiple cases on one compressor) to maintain different temperatures from a single compressor. Each case gets its own EPR set to the desired suction pressure. A stuck-open EPR means that case runs too cold; a stuck-closed EPR means it runs too warm or not at all.
- Evaporator coil
- The indoor heat exchanger where refrigerant absorbs heat from the cooled space. In walk-in coolers, the evaporator hangs inside the box with one or more fans pushing air across the coil. Evaporator failures (ice buildup, frozen-over coils, failed fan motors) are the most common single cause of "cooler not cooling" calls — usually a defrost-cycle problem or a door-seal problem causing humid air to freeze on the coil.
- Sight glass
- A small viewing port in the liquid line, just downstream of the receiver, that lets a tech see the refrigerant flow. A clear sight glass means proper charge and flow; bubbles or flashing indicates refrigerant undercharge or flow restriction; a wet/moisture indicator (built into most modern sight glasses) shows whether the system has been opened to atmosphere and has absorbed moisture.
- Suction line
- The larger-diameter copper line carrying low-pressure refrigerant vapor from the evaporator back to the compressor. Suction line temperatures are a key diagnostic input — a cold, sweating suction line at the compressor indicates floodback (liquid refrigerant returning to the compressor), which is a slow death sentence for the compressor.
- TXV (Thermostatic Expansion Valve)
- The metering device that controls refrigerant flow into the evaporator based on superheat at the evaporator outlet. A failed or stuck TXV is one of the most common causes of "cooler not cooling" calls in commercial refrigeration — symptoms include high evaporator superheat, low suction pressure, and inadequate cooling capacity. Replacement runs $200–$600 plus labor, depending on tonnage and equipment access.
Equipment types
- Blast chiller
- A high-output refrigeration unit designed to cool cooked food from 135°F to 41°F within 90 minutes — the FDA Food Code requirement for safely cooling cooked food without entering the bacterial growth danger zone. Common in larger production kitchens, hospitals, hotels, and meal-prep operations. Different refrigeration architecture from a regular cooler — much higher compressor capacity per cubic foot of storage.
- Display case
- Refrigerated cases used in grocery, deli, bakery, and food-service to display product for self-service. Includes upright cases (yogurt, deli meats), horizontal cases (frozen pizza), service cases (deli counter), and specialty cases (bakery, sushi, hot/cold). Open display cases run at higher refrigeration loads than reach-ins because of constant exposure to ambient air. Hussmann, Hill Phoenix (now ECP), and Kysor Warren are the dominant manufacturers.
- Ice machine
- A self-contained machine that produces ice — cube, flake, nugget, or specialty shapes — for restaurant, bar, hospitality, and healthcare use. Production rates run from 50 lbs/day (small bar units) to 2,000+ lbs/day (large restaurant or hotel units). Major brands: Hoshizaki, Manitowoc, Scotsman, Ice-O-Matic, Follett. Ice machines have the highest service-call frequency of any commercial refrigeration category because of mineral scale buildup from water; recommended PM is twice-yearly cleaning + descaling.
- Prep table
- A refrigerated work table combining a chilled storage section below with a rail-mounted topping insert above. Used heavily in sandwich shops, pizza kitchens, and Mexican-style restaurants. Prep table refrigeration is harder than reach-in because the open-top food pans expose refrigerated air to the kitchen. Frequent failures: door gasket degradation, condenser coil fouling from kitchen grease, evaporator fan motor failure.
- Reach-in refrigerator
- A self-contained commercial refrigerator with one to three doors, typically 27–82 inches wide. Used for line storage of prepped ingredients, beverages, and ready-to-serve items in restaurants. Reach-ins are usually self-contained (compressor mounted on top or bottom of the same cabinet), making them easier to service than walk-ins. Major brands include True, Beverage-Air, Continental, Delfield, and Traulsen.
- Walk-in cooler
- A walk-in refrigerated room maintained between 34°F and 40°F, used for bulk storage of perishables in restaurants, grocery, and food-service operations. Walk-in coolers range from 4×6 ft (smallest commercial units) to 20×30 ft+ for grocery and warehouse use. Refrigeration is provided by a remote condensing unit (typically roof-mounted) feeding one or more in-box evaporator units. Walk-in cooler service is the highest-frequency repair category in commercial refrigeration.
- Walk-in freezer
- A walk-in freezer room maintained between –10°F and 0°F for frozen food storage. Same basic architecture as a walk-in cooler but with lower-temperature refrigerant, more aggressive defrost cycles, and heavier insulation (typically 4-inch panel walls vs 3-inch for coolers). Walk-in freezers have shorter equipment life than coolers because compressors run harder against larger temperature differentials.
Brands
- Copeland
- The dominant manufacturer of commercial refrigeration compressors — particularly the Copelametic and Scroll product lines. Copeland was part of Emerson Climate Technologies and is now branded under the Copeland name following Emerson's 2023 separation. Any walk-in cooler installed in the US has a high probability of running a Copeland compressor; brand-specific replacement parts are readily available through any refrigeration distributor.
- Hoshizaki
- Japanese manufacturer of commercial ice machines, refrigerators, and prep tables. Hoshizaki ice machines are widely considered the most reliable in the industry — sometimes nicknamed "the Toyota of ice machines." Service techs trained on Hoshizaki tend to charge a slight premium because the brand-specific diagnostic procedures and parts inventory matter.
- Hussmann
- One of the largest US manufacturers of commercial refrigeration for supermarkets, convenience stores, and food retail. Owned by Panasonic. Hussmann display cases dominate the supermarket walk-in / open-case market. Service-tech rule: any tech servicing supermarket refrigeration needs Hussmann experience.
- Manitowoc
- Major US-based manufacturer of commercial ice machines (now part of Welbilt). Manitowoc dominates the modular ice machine market — the cube-and-bin configuration where a separate ice machine sits on top of a separate storage bin. Service techs need brand-specific training because Manitowoc's control board diagnostics differ from Hoshizaki and Scotsman.
- Scotsman
- US-based manufacturer of commercial ice machines including the Prodigy and Brilliance lines. Scotsman is particularly strong in nugget-ice and flake-ice production, used in healthcare, hospitality, and specialty foodservice.
- True
- The dominant US brand for foodservice reach-in refrigerators, prep tables, beverage coolers, and self-contained equipment. Headquartered in O'Fallon, Missouri. True's service network is broad and parts are well-stocked at most commercial refrigeration distributors. If a restaurant has a single piece of refrigeration equipment, it's usually True.
Regulations & certifications
- AIM Act
- The American Innovation and Manufacturing Act, signed December 2020, gives the EPA authority to phase down hydrofluorocarbons (HFCs) by 85% between 2022 and 2036. The phase-down schedule directly affects commercial refrigeration — R-404A and R-507A are essentially being legislated out of new equipment, and all R-22 servicing now depends on reclaimed-only supply.
- CFESA
- Commercial Food Equipment Service Association — the industry trade group for foodservice equipment service companies. CFESA member companies have completed training in foodservice equipment repair specifically (vs general HVAC/R). CFESA certification is a meaningful trust signal when sourcing service for restaurant equipment.
- EPA Section 608
- Federal regulation under the Clean Air Act requiring any technician who works with refrigerants to hold an EPA 608 certification. Four certification types: Type I (small appliances), Type II (high-pressure systems — most commercial refrigeration), Type III (low-pressure systems), and Universal (all three). Any commercial refrigeration repair tech must hold at least Type II. Confirming the cert is the first thing operators should ask when evaluating a new service provider — anyone working without it is breaking federal law.
- FDA Food Code
- The model food-safety regulation maintained by the FDA, updated every 4 years (current version: 2022). Adopted in whole or in part by every US state for restaurant and foodservice regulation. Key refrigeration requirements: cold-held TCS food at or below 41°F, frozen food at or below 0°F, cooked-food cooling from 135°F to 70°F within 2 hours and 70°F to 41°F within 4 more hours.
- NATE certification
- North American Technician Excellence — a voluntary certification that goes beyond the legally-required EPA 608. NATE-certified techs have passed specialty exams in commercial refrigeration, light commercial AC, heat pumps, or other HVAC/R areas. NATE is the premium credential — operators looking for the highest service quality typically prefer NATE-certified providers and often pay 10–20% more per service call.
- SNAP rules
- EPA's Significant New Alternatives Policy program — the rules that determine which refrigerants are approved for which equipment types in the US. SNAP Rule 26 (effective 2025) restricts new commercial refrigeration equipment to refrigerants with GWP under ~700 in most categories, accelerating the move from R-404A/R-507A to R-448A/R-449A/R-454C/R-290.
- TCS food
- Time/Temperature Control for Safety food — the FDA Food Code category for foods that support rapid bacterial growth and must be held at or below 41°F. Includes proteins (meat, poultry, seafood, eggs, dairy), cut produce (cut leafy greens, cut tomatoes, cut melons), cooked rice/pasta/beans, and any cooked vegetable. If walk-in cooler temperature exceeds 41°F for more than 4 hours, all TCS food must be discarded by health-code regulation.
Concepts
- Defrost cycle
- The automatic process that melts frost off an evaporator coil. Three common methods: time-initiated (a timer triggers defrost on a set schedule), demand-initiated (a sensor detects frost buildup and triggers), and hot-gas defrost (uses compressor discharge gas to defrost rapidly). Failed defrost = frozen-over evaporator = no cooling. Fixing a defrost issue can be as simple as resetting a timer ($0) or as complex as replacing a defrost heater ($300–$600).
- GWP (Global Warming Potential)
- A measure of how much heat a refrigerant traps in the atmosphere relative to CO₂ over 100 years. CO₂ has GWP = 1. R-22 has GWP = 1,810. R-404A has GWP = 3,922. R-454C has GWP = 148. R-290 (propane) has GWP = 3. The AIM Act and SNAP rules use GWP thresholds to determine which refrigerants can be sold for which applications.
- Head pressure
- The pressure at the compressor discharge (high side). For R-404A walk-in coolers, normal head pressure runs 220–280 PSIG depending on ambient temperature. High head pressure = dirty condenser, failed condenser fan, refrigerant overcharge, or non-condensables in the system. Low head pressure = refrigerant undercharge or ambient too cold for proper operation.
- Preventive maintenance (PM)
- Scheduled inspection and service performed before equipment fails — typically twice yearly for commercial refrigeration. Standard PM scope: condenser coil cleaning, evaporator coil inspection, refrigerant charge check, door gasket inspection, electrical contact inspection, drain line cleaning, defrost cycle verification. Industry data: restaurants with twice-yearly PM see 40–60% fewer emergency service calls and 25% longer equipment life.
- Refrigerant leak
- A loss of refrigerant from a refrigeration system through a failed joint, corroded coil, or damaged copper line. Symptoms include slow loss of cooling capacity, ice on the suction line, hissing at the leak point, and an oily film around joints (refrigerant carries compressor oil out with it). EPA 608 regulations require leaks to be fixed before recharging — "topping up" without repair is illegal. Diagnostic methods: electronic detector, soap-bubble test, dye injection, ultrasonic.
- Service-level agreement (SLA)
- A contracted commitment between a refrigeration service provider and a restaurant operator specifying response times, hours of coverage, and pricing. Typical SLA terms include 4-hour response for emergencies, 24-hour response for non-emergencies, twice-yearly preventive maintenance, and discounted parts pricing. SLA pricing typically runs $200–$500/month per location. Restaurant operators running 24/7 (bars, hospitality) almost always benefit from a written SLA over pay-per-call service.
- Subcooling
- The temperature of the liquid refrigerant at the condenser outlet below its condensing (saturation) temperature. Target subcooling is typically 8–15°F. Low subcooling indicates a refrigerant undercharge or condenser issue; very high subcooling can indicate overcharge or restriction. Together with superheat, subcooling is the key gauge reading techs use to diagnose system performance.
- Superheat
- The temperature of the refrigerant gas at the evaporator outlet above its boiling temperature at that pressure. Proper superheat (typically 8–12°F at the evaporator outlet for commercial refrigeration) indicates the TXV is metering refrigerant correctly. Too high = under-charged or TXV too closed; too low = over-charged or TXV too open. Measuring superheat is the standard first diagnostic any commercial refrigeration tech performs on a service call.
- Twinning
- Running two compressors in parallel feeding a single refrigerated space, with controls that stage them on and off based on cooling demand. Twinned systems provide redundancy (one compressor failure doesn't lose the box), modulation (lower energy use at part-load), and higher peak capacity. Common in larger walk-ins (12×16 ft+) and supermarket applications. More expensive to install but worth it for high-value inventory.