Valve cores are essential components in HVAC and refrigeration systems, ensuring secure refrigerant flow and system integrity. Choosing the right type—like Schrader or specialty cores—can dramatically impact performance, maintenance, and safety.
Mbsmpro.com, HVAC Valve Core, Schrader Type, Brass Body, R134a, 1/4 SAE, Pressure Seal, Refrigeration, Air Conditioning, Service Port, Leak Prevention, SAE J-639, ISO Certified
Understanding HVAC Valve Cores: Types, Applications, and Engineering Insights
Valve cores are the unsung heroes of HVAC and refrigeration systems. These small yet critical components regulate refrigerant flow, maintain pressure integrity, and enable safe servicing. The most common type is the Schrader valve core, widely used in automotive and stationary air conditioning systems.
Use brass cores for general HVAC applications due to corrosion resistance and durability.
Always verify SAE J-639 compliance for automotive systems to ensure safety and compatibility.
Replace valve cores during every refrigerant recharge to prevent micro-leaks.
Use core removal tools to avoid damaging threads and seals.
Benefits of Proper Valve Core Selection
Improved system efficiency through optimal refrigerant flow.
Reduced maintenance costs by preventing leaks and pressure loss.
Enhanced safety during servicing and operation.
Extended equipment lifespan due to reduced wear on seals and fittings.
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Schrader Pacific A/C Valve Manual (PDF)
ConnectMe HVAC Valve Core Selection Guide
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Discover the engineering essentials of HVAC valve cores, including Schrader types, pressure ratings, material specs, and best practices for leak prevention and system efficiency.
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Valve cores are vital for HVAC and refrigeration systems. This guide explores Schrader valve types, pressure ratings, material choices, and engineering tips for optimal performance and leak prevention.
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Mbsmpro.com, HVAC Valve Core, Schrader Type, Brass Body, R134a, 1/4 SAE, Pressure Seal, Refrigeration, Air Conditioning, Service Port, Leak Prevention, SAE J-639, ISO Certified
Valve cores are the unsung heroes of HVAC and refrigeration systems. These small yet critical components regulate refrigerant flow, maintain pressure integrity, and enable safe servicing. The most common type is the Schrader valve core, widely used in automotive and stationary air conditioning systems.
Valve cores are vital for HVAC and refrigeration systems. This guide explores Schrader valve types, pressure ratings, material choices, and engineering tips for optimal performance and leak prevention.
Focus Keyphrase: HVAC valve core Schrader type brass body R134a 1/4 SAE pressure seal refrigeration air conditioning service port leak prevention SAE J-639 ISO certified
Meta Description: Discover the engineering essentials of HVAC valve cores, including Schrader types, pressure ratings, material specs, and best practices for leak prevention and system efficiency.
Tags: Mbsmgroup, Mbsm.pro, mbsmpro.com, mbsm, HVAC, refrigeration, valve core, Schrader, R134a, service port, pressure seal, SAE J-639, ISO
Excerpt: Valve cores are vital for HVAC and refrigeration systems. This guide explores Schrader valve types, pressure ratings, material choices, and engineering tips for optimal performance and leak prevention.
HITACHI FL20S88NAA Compressor Specifications: Complete Technical Guide for Sharp Refrigerators with HFC-134a R134a 220-240V 50Hz LBP
Comprehensive technical documentation on the HITACHI FL20S88NAA 0.75 HP refrigeration compressor and its integration in the Sharp SJ-PT73R-HS3 refrigerator-freezer unit. This professional guide covers compressor specifications, operating principles, performance comparisons, pressure classifications, and maintenance essentials for HVAC and refrigeration professionals.
Understanding the HITACHI FL20S88NAA Compressor: Core Specifications and Technical Characteristics
The HITACHI FL20S88NAA represents a critical component in small to medium-capacity refrigeration systems, specifically engineered for household refrigerator-freezer applications. This hermetic, scroll-based compressor operates on the low back pressure (LBP) principle, making it ideal for maintaining temperature ranges between −30°C and −10°C—the optimal zone for freezer compartments with secondary refrigeration cycles for fresh food storage. Manufactured on December 16, 2009, and bearing serial number 65447, this compressor demonstrates the robust engineering standards that established HITACHI’s reputation in refrigeration technology across the Asian and European markets.
The FL20S88NAA designation itself contains critical encoded information for technicians and engineers. The “FL” prefix indicates the Rotary Scroll Compressor Series, while “20” refers to the approximate displacement volume of 20.6 cubic centimeters per revolution. This displacement capacity, combined with 50Hz operation at 220-240V single-phase input, produces a rated cooling capacity of approximately 256 watts under ASHRAE test conditions—a specification that aligns with the energy demands of mid-size refrigerators ranging from 550 to 700 liters gross volume.
The compressor utilizes HFC-134a (R134a) refrigerant, a hydrofluorocarbon that has been the industry standard for household refrigeration since the phase-out of CFC-12 under the Montreal Protocol. The 110-gram charge specified for the Sharp SJ-PT73R-HS3 unit represents a carefully calibrated mass that balances system efficiency with environmental responsibility—HFC-134a has zero ozone depletion potential while maintaining favorable thermodynamic properties for small-scale refrigeration applications.
Pressure Classification and Operating Principles: LBP vs. Other Pressure Categories
The LBP (Low Back Pressure) designation distinguishes the FL20S88NAA from its medium back pressure (MBP) and high back pressure (HBP) counterparts, a classification system that directly reflects the compressor’s evaporating temperature operational range and intended application environment. Understanding this distinction is essential for proper compressor selection, replacement procedures, and system diagnostics.
Low Back Pressure (LBP) compressors like the FL20S88NAA are optimized for evaporating temperatures typically ranging from −10°C down to −35°C or lower, making them the standard choice for deep freezers, freezer compartments in refrigerators, and preservation units where sustained low temperatures are required. These compressors operate efficiently when the suction-side pressure remains low, which occurs naturally when the evaporator temperature is substantially below the ambient cooling environment.
The compression ratio—the mathematical relationship between discharge pressure and suction pressure—becomes critically important when analyzing LBP versus MBP performance. The FL20S88NAA’s LBP optimization means it achieves maximum volumetric efficiency when operating across the wider pressure differential inherent in freezer systems, but attempting to operate this same compressor in an MBP application (such as a beverage cooler) would result in reduced cooling capacity, potential motor overheating, and shortened service life.
Electrical Specifications and Motor Design: RSIR Starting Method
The electrical configuration of the FL20S88NAA incorporates the RSIR (Resistance Start, Induction Run) starting method—a proven design approach that uses the compressor motor’s run capacitor combined with a starting relay to achieve reliable cold starts without requiring additional starting capacitor hardware. This single-phase motor configuration accepts 220-240V at 50Hz frequency, with a rated current draw of approximately 1.2-1.3A during normal operation, producing a motor input of 145-170 watts.
The RSIR designation indicates that the compressor motor windings are designed with intentional resistance differential between the start and run coils, creating the phase shift necessary to produce rotating magnetic fields during the initial acceleration phase. Once the motor reaches approximately 75% of its synchronous speed, the starting relay mechanism automatically disconnects the start coil circuit, and the motor continues operating on the run coil alone—a configuration offering several advantages over alternative starting methods:
Advantages of RSIR Design:
Simplified Control Circuitry: Eliminates the need for dedicated starting capacitors, reducing component count and complexity
Reliable Cold Starts: Provides adequate starting torque even after extended shutdown periods when gas pressures have equalized
Extended Motor Life: The reduced electrical stress during startup contributes to longer operational life compared to capacitor-start designs
Cost Effectiveness: Lower manufacturing complexity translates to reduced acquisition costs
The Sharp SJ-PT73R-HS3 Refrigerator: Integration and Performance Specifications
The SHARP SJ-PT73R-HS3 represents a mid-range, dual-chamber refrigerator-freezer unit engineered around the FL20S88NAA compressor as its primary cooling agent. With a gross storage volume of 662 liters and net capacity of 555 liters, this model exemplifies the contemporary approach to household refrigeration, combining traditional vapor-compression cooling technology with advanced supplementary systems for enhanced freshness retention.
The refrigerator’s physical footprint—800mm width, 1770mm height, and 720mm depth—accommodates standard kitchen layouts while maximizing internal storage efficiency through the Hybrid Cooling System. This technology employs an aluminum panel cooled to approximately 0°C, which acts as an intermediary heat sink. Rather than exposing food directly to rapid cold air circulation (which causes dehydration), the Hybrid Cooling System distributes temperature-controlled air more gradually across all compartments, maintaining humidity levels while preventing moisture loss from produce and fresh items.
The electrical specifications indicate a refrigerant charge of 110 grams HFC-134a and insulation blowing gas consisting of cyclo pentane (a hydrocarbon substitute for CFCs). The unit’s net weight of 82 kilograms reflects substantial internal copper piping, aluminum evaporator surfaces, and the insulation foam layer manufactured with flammable blowing agents—an environmental trade-off that reduces global warming potential while introducing manageable thermal stability requirements.
Refrigerant Properties and System Thermodynamics: HFC-134a Characteristics
HFC-134a (Hydrofluorocarbon-134a, also marketed as Freon™ 134a) possesses specific thermodynamic properties that make it uniquely suited for small hermetic refrigeration systems like the FL20S88NAA. With a boiling point of −26.06°C at one atmosphere and a critical temperature of 101.08°C, HFC-134a occupies a favorable operating envelope for household refrigeration where evaporator temperatures range from −30°C to +5°C and condenser temperatures typically reach 40−60°C.
The refrigerant’s molecular weight of 102.03 g/mol and critical pressure of 4060.3 kPa absolute influence the pressure-temperature relationships critical for technician diagnostics. At an evaporating temperature of −23.3°C (ASHRAE rating condition), HFC-134a exhibits a saturation pressure of approximately 1.0 bar absolute, while at a condensing temperature of 54.4°C (130°F), the saturation pressure rises to approximately 10.6 bar absolute—a pressure ratio of roughly 10:1 that the FL20S88NAA’s displacement and motor design accommodate efficiently.
The solubility of HFC-134a in mineral oil adds complexity to compressor oil selection and system lubrication strategy. The refrigerant dissolves in the compressor’s mineral oil lubricant to varying degrees depending on temperature and pressure conditions. This miscibility is essential for proper motor cooling and bearing lubrication but requires careful attention during system service—oil contamination with air or moisture accelerates acid formation, potentially damaging motor insulation and compressor valve surfaces.
Displacement Volume and Cooling Capacity Performance Analysis
The FL20S88NAA’s 20.6 cm³ displacement per revolution, operating at 50Hz (3000 RPM nominal synchronous speed, typically 2800-2900 RPM actual), theoretically moves approximately 617 cm³ (0.617 liters) of refrigerant gas per minute under full-speed operation. However, actual volumetric efficiency—the percentage of theoretical displacement that translates to useful refrigerant circulation—typically ranges from 65−85% depending on system operating conditions, suction line pressure, and compressor wear characteristics.
The 256-watt cooling capacity specification deserves careful interpretation. This measurement represents the heat removal rate (in joules per second) achieved under standardized ASHRAE test conditions: evaporating temperature of −23.3°C, condensing temperature of 54.4°C, and subcooled liquid entering the expansion device. This cooling capacity represents the actual useful heat transfer occurring at the evaporator surface, not the total energy input to the system. The relationship between cooling capacity, displacement, and power input defines the Coefficient of Performance (COP)—a unitless metric expressing system efficiency:
COP = Cooling Capacity (W) / Compressor Power Input (W)
For the FL20S88NAA operating near design conditions: COP ≈ 256 W / 160 W ≈ 1.6
This 1.6 COP indicates that for every watt of electrical energy supplied to the motor, the system removes 1.6 watts of heat from the refrigerated space—a reasonable efficiency level for small hermetic compressors operating under typical household refrigeration loads.
Starting Method, Relay Operation, and Control System Integration
The RSIR (Resistance Start, Induction Run) starting methodology employed by the FL20S88NAA requires careful coordination between the motor windings, starting relay, and compressor discharge pressure characteristics. During the startup sequence—the critical 0−3 second period when the motor must accelerate from zero to approximately 75% synchronous speed—the starting relay circuit permits current through both main and auxiliary motor windings, creating the requisite rotating magnetic field.
As motor speed increases, back EMF (electromotive force) builds in the run winding. When back EMF reaches approximately 75% of applied voltage, the pressure equalization mechanism integrated into the compressor discharge line equalizes internal pressures, reducing the starting torque requirement. Simultaneously, the starting relay detects this speed increase through a combination of current sensing and mechanical timing, automatically opening the starting circuit.
The Sharp SJ-PT73R-HS3’s electronic control system monitors refrigerator and freezer compartment temperatures through thermistor sensors, determining when to activate the compressor. A typical refrigeration cycle operates on an ON/OFF basis: when freezer temperature rises above the setpoint (typically −18°C), the thermostat closes a relay contact, energizing the compressor motor. The motor runs continuously until evaporator temperature drops to satisfy the freezer setpoint, at which point the thermostat opens the relay, stopping the compressor. This simple but effective control strategy suits the thermal mass and insulation characteristics of large household refrigerators.
Comparison with Modern Inverter Compressors and Energy Efficiency Implications
Contemporary refrigerator designs increasingly incorporate inverter compressors—variable-speed motors controlled by electronic inverter drives that adjust compressor speed continuously based on cooling demand. Sharp’s J-Tech Inverter technology, featured in their premium refrigerator models, offers substantial energy savings compared to fixed-speed designs like those utilizing the FL20S88NAA.
Performance Parameter
Fixed-Speed (FL20S88NAA Type)
Inverter-Based System
Improvement
Energy Consumption
100% (baseline)
60−70%
30−40% reduction
Noise Level
100% (baseline)
~50%
50% noise reduction
Vibration
100% (baseline)
~70%
30% vibration reduction
Temperature Stability
±3−5°C variance
±0.5−1°C variance
Significantly improved
Compressor On/Off Cycles
~8−15 per hour
~50+ per hour (variable speed)
More stable operation
The energy efficiency advantage stems from compressor speed modulation. Fixed-speed compressors like the FL20S88NAA operate in a binary mode: either running at full displacement (consuming maximum power) or completely stopped. During partial-load conditions—when the refrigerator’s cooling requirement is less than the compressor’s full capacity—the system cycles on and off frequently, wasting energy during starting transients and experiencing temperature overshoot/undershoot between cycles.
Inverter systems address this through continuous variable-speed operation. When cooling demand decreases, the inverter electronics progressively reduce motor frequency and voltage, allowing the compressor to operate at lower displacement rates. This eliminates the energy waste from repeated start/stop cycles and maintains more stable compartment temperatures. Testing by Sharp indicates approximately 40% faster ice cube formation and 10% additional energy savings in Eco Mode compared to conventional fixed-speed designs.
Oil Charge Requirements and Lubrication Considerations
The FL20S88NAA specification calls for precisely 220 grams of mineral-based compressor oil—a critical parameter that directly affects motor cooling, bearing lubrication, and long-term compressor reliability. Insufficient oil reduces bearing film thickness and motor cooling effectiveness, while excess oil impairs heat transfer at the motor windings and can damage the expansion valve through oil slugging (liquid oil being pumped into the evaporator discharge line).
The oil selection process involves considering the refrigerant miscibility characteristics. HFC-134a systems typically employ mineral oils with kinematic viscosity around 32 cSt at 40°C, a standard that balances viscous film strength at bearing surfaces with the reduced viscosity that occurs when refrigerant dissolves in the oil during system operation. At typical operating temperatures (motor discharge reaching 80−100°C), the combined refrigerant-oil mixture maintains adequate viscosity for bearing protection while allowing efficient heat transfer away from motor windings.
Maintenance, Diagnostics, and Service Considerations
Professional HVAC technicians servicing the Sharp SJ-PT73R-HS3 or similar systems using the FL20S88NAA require specific diagnostic approaches. Key parameters to monitor include:
Suction Pressure Monitoring: At the compressor inlet, steady-state suction pressure should reflect the evaporating temperature. For −23.3°C ASHRAE conditions, expect approximately 1.0 bar absolute. Abnormally high suction pressure suggests restricted refrigerant metering (plugged expansion valve), while low suction pressure indicates insufficient evaporator heat absorption or refrigerant charge loss.
Discharge Pressure Analysis: Condensing temperature directly influences discharge pressure. At typical ambient conditions (27°C kitchen temperature), expect discharge pressures of 8−12 bar absolute. Excessively high discharge pressure (>14 bar) indicates condenser fouling, non-condensables in the refrigerant circuit, or restriction in the discharge line. Abnormally low discharge pressure suggests superheated refrigerant or loss of refrigerant charge.
Motor Current Signature Analysis: The FL20S88NAA’s rated run current of 1.2−1.3A provides a baseline for condition assessment. Elevated current draw (>1.5A sustained) indicates either elevated system pressures (condenser dirty, high ambient temperature) or motor winding degradation. Diminished current draw (<1.0A) suggests insufficient load, possibly from low system pressures from refrigerant loss.
Liquid Line Temperature: Ideally, the high-pressure liquid exiting the condenser should be 5−10°C above ambient. This “subcooling” indicates proper refrigerant charge levels and condenser performance. Insufficient subcooling suggests low charge or poor condenser air flow; excessive subcooling (>15°C above ambient) may indicate excess charge or expansion valve malfunction.
Compatibility, Retrofitting, and Replacement Considerations
The FL20S88NAA occupies a specific application niche that has remained largely stable since its introduction in 2009, reflecting the standardization of household refrigerator designs. When replacement becomes necessary—typically after 15−20 years of operation or following mechanical failure—technicians must carefully assess compatible alternatives.
Direct Replacement Options: The HITACHI FL20H88-TAA represents a direct successor, offering identical displacement but enhanced efficiency. The H-series designation indicates “Improved” performance characteristics.
HFC-134a Retrofitting: Any replacement compressor must be HFC-134a compatible. Retrofitting from older CFC-12 or HCFC-22 systems to R134a requires not only compressor replacement but also expansion valve adjustment (R134a typically requires finer orifice sizing), lubricant conversion (synthetic polyol ester oils for R134a vs. mineral oils for CFC-12), and sometimes condenser enhancement due to R134a’s different heat transfer characteristics.
Cross-Reference Challenges: Different manufacturers encode compressor specifications differently. A technician replacing the FL20S88NAA might encounter GMCC, Copeland, or Tecumseh alternatives with fundamentally equivalent displacement and pressure ratings. Success requires consulting manufacturer’s cross-reference tables and verifying that replacement units operate at 220-240V/50Hz and suit LBP applications.
Conclusion: Integration of Compressor Technology in Modern Refrigerator Systems
The HITACHI FL20S88NAA compressor embedded within the Sharp SJ-PT73R-HS3 refrigerator-freezer unit exemplifies the technical sophistication underlying everyday household appliances. This 0.75-horsepower hermetic scroll compressor, optimized for 220-240V/50Hz operation with HFC-134a refrigerant and LBP pressure characteristics, delivers approximately 256 watts of cooling capacity while consuming just 160 watts of electrical power—a 1.6 COP that reflects decades of incremental engineering refinement.
The integration of the Hybrid Cooling System, electronic temperature control, and RSIR-method starting represents a balanced approach to refrigerant-based heat transfer, prioritizing reliability and simplicity over the variable-speed sophistication now becoming standard in premium models. For regions utilizing 50Hz electrical infrastructure and requiring robust, serviceable refrigeration systems, the specifications outlined herein provide both immediate diagnostic guidance and long-term maintenance planning tools.
As the refrigeration industry transitions toward next-generation compressor technologies—incorporating variable-speed inverter drives, alternative refrigerants such as HFO-1234yf and hydrofluoroolefins (HFOs) for reduced global warming potential, and AI-enabled predictive maintenance systems—the FL20S88NAA remains an instructive reference point for understanding the thermodynamic principles that continue to govern small-scale refrigeration applications worldwide.
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Meta Description (Optimal length 155-160 characters): Professional guide to HITACHI FL20S88NAA 0.75 HP refrigerator compressor. Specifications, LBP pressure classification, HFC-134a refrigerant, operating principles for technicians.
Excerpt (First 55 words): The HITACHI FL20S88NAA 0.75 HP hermetic scroll compressor delivers 256W cooling capacity at 50Hz, utilizing HFC-134a refrigerant for household refrigerator-freezer applications. This LBP-classified unit operates reliably at 220-240V with RSIR starting method, integrated into Sharp’s SJ-PT73R-HS3 model offering 662-liter gross capacity with Hybrid Cooling System and Plasmacluster technology.
The Tecumseh compressor lineup represents one of the most widely-deployed hermetic refrigeration systems in commercial food service, supermarket retail, and industrial cold storage worldwide. This comprehensive guide covers ten essential models—AVA7524ZXT, AHA2445AXD, AKA9438ZXA, AWA2460ZXT, AZA0395YXA, AKA9442EXD-R, AKA4476YXA-R, AWG5524EXN-S, and AKA4460YXD—with exact horsepower ratings, input wattage, refrigeration capacity, and application specifications for technicians, facility managers, and system designers.
Complete Specifications Table: All Ten Tecumseh Compressor Models
Model
HP Rating
Input Watts (Rated)
Refrigeration Capacity (W)
Refrigerant
Voltage/Phase
Evaporating Range
Application Type
Motor Type
AVA7524ZXT
3 HP
3,490–4,000 W (varies by refrigerant)
6,639–6,973 W (R407A-R404A @ 20°F evap.)
R404A, R407A, R448A, R449A, R452A
200–230V 3-phase 60Hz / 50Hz
−23.3°C to −1.1°C (−10°F to 30°F)
Medium-Back-Pressure (MBP)
HST (High Start Torque) 3-phase
AHA2445AXD
1 HP
1,225 W (R-12 @ −10°F evap.)
1,289 W (legacy R-12)
R-12 (inactive/restricted)
200–230V 1-phase 50/60Hz
−40°C to −12.2°C (−40°F to 10°F)
Low-Back-Pressure (LBP)
CSIR (Capacitor-Start) HST
AKA9438ZXA
1/2 HP
756 W (R404A @ 20°F evap.)
1,099–1,112 W (R404A-R407A)
R404A, R407A, R448A, R449A, R452A
115V 1-phase 60Hz / 100V 50Hz
−17.8°C to 10°C (0°F to 50°F)
Commercial-Back-Pressure (CBP)
CSIR HST
AWA2460ZXT
1.5 HP
1,552–1,686 W (R452A-R449A)
1,684–1,758 W (−10°F evap.)
R404A, R407A, R448A, R449A, R452A
200–230V 3-phase 50/60Hz
−40°C to −12.2°C (−40°F to 10°F)
Low-Back-Pressure (LBP)
HST 3-phase
AZA0395YXA
1/9 HP
230 W (R134a @ 20°F evap.)
278 W (R134a)
R-134a
115V 1-phase 60Hz / 100V 50Hz
−17.8°C to 10°C (0°F to 50°F)
Commercial-Back-Pressure (CBP)
RSIR (Rotary Solenoid) LST
AKA9442EXD-R
1/2 HP
760 W (R-22 @ 20°F evap.)
1,231 W (R-22)
R-22, R-407C
208–230V 1-phase 60Hz / 200V 50Hz
−17.8°C to 10°C (0°F to 50°F)
Commercial-Back-Pressure (CBP)
CSR (Capacitor-Start) HST
AKA4476YXA-R
3/4 HP
1,070–1,111 W (R134a-R513A)
2,250–2,265 W (45°F evap.)
R-134a, R-513A
115V 1-phase 60Hz / 100V 50Hz
−6.7°C to 12.8°C (20°F to 55°F)
High-Back-Pressure (HBP)
CSIR HST
AWG5524EXN-S
2 HP
1,650–2,480 W (varies load)
7,091 W (R-22 rated)
R-22, R-407C
208–230V 1-phase 60Hz / 200–220V 50Hz
−23.3°C to 12.8°C (−10°F to 55°F)
Multi-Temperature
PSC LST
AKA4460YXD
1/2 HP
889–890 W (R134a HT)
6,250 BTU/h (~1,830 W) @ 20°F evap.
R-134a (high-temperature rated)
208–230V 1-phase 60Hz
−6.7°C to 12.8°C (20°F to 55°F)
High-Back-Pressure (HBP)
CSIR HST
Detailed Model Analysis with Exact Power Specifications
AVA7524ZXT: 3 HP, 3,490–4,000 W Medium-Back-Pressure Workhorse
The Tecumseh AVA7524ZXT is one of the company’s flagship 3-horsepower, three-phase compressors with input power consumption ranging from 3,490 W to 4,000 W depending on refrigerant and operating conditions. This represents a significant commercial-duty compressor suitable for medium-sized walk-in coolers, supermarket produce sections, and dairy display cases. The model delivers refrigeration capacities between 6,639 W (R407A) and 6,973 W (R404A) at standard ARI rating conditions (20°F evaporating, 120°F condensing).
Power Consumption Breakdown by Refrigerant at 20°F Evaporation:
R404A: 4,000 W input (Most demanding; highest discharge temperature)
R449A: 3,622 W input (Better efficiency than R404A)
R448A: 3,622 W input (Similar to R449A; lower GWP)
R452A: 3,772 W input (Improved efficiency; very low GWP)
R407A: 3,490 W input (Most efficient; legacy alternative)
The high three-phase inrush current (65.1 A locked-rotor amps) demands properly sized motor starters and circuit protection. Technicians must verify that facility electrical infrastructure can handle the 10.9 A rated load at 60 Hz continuously without voltage sag exceeding 3%.
Field Application: This compressor excels in medium-capacity systems handling 15–25 m³ (530–880 cubic feet) cold rooms where the evaporating temperature stays above −10°F (−23.3°C) and cooling loads are moderate to heavy. Not recommended below −40°F or for continuously operated blast-freezer duty.
AHA2445AXD: 1 HP, 1,225 W Legacy Low-Temperature R-12 Unit
The Tecumseh AHA2445AXD is a 1-horsepower, single-phase compressor rated for 1,225 W input power at the ASHRAE standard low-temperature rating (−10°F evaporating, 130°F condensing). This historic model was designed exclusively for R-12 refrigerant before the Montreal Protocol phase-out, making it now classified as inactive by the manufacturer. Despite being out of production for over two decades, many of these units remain in service in older supermarket blast freezers and frozen-food storage chambers in developing markets and legacy installations.
Critical Specifications:
Refrigeration Capacity: 1,289 W @ −10°F evaporation (ASHRAE standard)
Motor Configuration: CSIR (Capacitor-Start/Induction-Run) with High Start Torque
Locked-Rotor Amps: 51 A (high inrush current requiring heavy-duty contactors)
Displacement: 53.186 cc (relatively small piston chamber)
Oil Type: Mineral oil (incompatible with modern POE-based refrigerants)
Why It’s Obsolete: R-12 recovery is mandatory in most developed nations; supplies are restricted to legacy system maintenance only. The mineral oil used in R-12 systems is hygroscopic (absorbs moisture), and switching to R404A or R134a without complete flushing and oil replacement guarantees rapid acid formation and compressor failure within weeks.
Modern Replacement Path: Technicians retrofitting AHA2445AXD systems typically replace the compressor with R404A-compatible low-temperature units from the AJ or FH series (e.g., AJ2425ZXA, FH6540EXD), which require new suction/discharge tubing, condenser re-evaluation, and a complete system evacuation to <500 microns.
AKA9438ZXA: 1/2 HP, 756 W Compact Commercial Medium-Temperature
The Tecumseh AKA9438ZXA is a compact 1/2-horsepower compressor drawing just 756 W input power at R404A rating conditions (20°F evaporation). Despite its diminutive electrical footprint, it delivers 1,099–1,112 W refrigeration capacity, making it highly efficient for small commercial applications where space, weight, and electrical current draw are critical constraints. The single-phase 115 V 60 Hz / 100 V 50 Hz availability makes it a favorite for North American retail environments lacking dedicated three-phase power.
Performance and Electrical Profile:
Refrigerant
Input Watts
Capacity Watts
Locked-Rotor Amps
Rated Load Amps
R404A
800 W
1,099 W
58.8 A
9.2 A
R407A
756 W
1,112 W
58.8 A
9.2 A
R449A
724 W
1,094 W
58.8 A
9.2 A
R452A
757 W
1,092 W
58.8 A
9.2 A
R448A
724 W
1,094 W
58.8 A
9.2 A
Critical Field Consideration: The high locked-rotor current (58.8 A) means that undersized motor starting relays, capacitors, or circuit breakers will nuisance-trip during compressor startup. Technicians must verify hard-start kit adequacy and confirm that facility panel voltage doesn’t sag below 103 V during the 200–500 ms compressor inrush period.
Ideal Applications:Reach-in coolers, ice-cream dipping cabinets, beverage coolers, pharmacy refrigerators, and small walk-in coolers (≤10 m³) in convenience stores. The evaporating range of 0°F to 50°F (−17.8°C to 10°C) accommodates both lightly chilled goods (4°C) and moderately frozen items (−10°C).
AWA2460ZXT: 1.5 HP, 1,552–1,686 W Three-Phase Low-Temperature
The Tecumseh AWA2460ZXT is a 1.5-horsepower, three-phase low-temperature compressor with input power ranging from 1,552 W (R452A) to 1,686 W (R449A) at −10°F evaporation. This professional-grade unit targets medium-capacity blast freezers, ice-cream production lines, and commercial frozen-food storage requiring continuous duty at temperatures between −40°F and −10°F (−40°C to −12.2°C).
Power Efficiency Comparison Across Refrigerants (230 V 3-phase, −10°F evaporation):
Refrigerant
Input Watts
Refrigeration Capacity (W)
Efficiency (W/W)
Discharge Temp. Trend
R404A
1,630 W
1,758 W
1.08
Baseline
R449A
1,686 W
1,684 W
1.00
Higher; more discharge heat
R448A
1,686 W
1,684 W
1.00
Similar to R449A
R452A
1,552 W
1,719 W
1.11
Lowest input; best COP
Three-Phase Electrical Requirements:
Locked-Rotor Amps (LRA): 63.4 A (substantial; requires oversized contactor)
Displacement: 51.27 cc (large piston volume for high-displacement performance)
Operational Excellence: The AWA2460ZXT shines in consistent, heavy-duty freezer service where uninterrupted cooling at −20°F to −30°F is essential for product quality. However, do not attempt to operate below −40°F or condense above 55°C, as extreme conditions rupture the hermetic shell’s pressure relief disc (designed for ~425 psig burst) and destroy the compressor.
AZA0395YXA: 1/9 HP, 230 W Micro-Displacement Extended-Temperature
The Tecumseh AZA0395YXA represents a tiny 1/9-horsepower compressor with only 230 W input power consumption at ARI rating conditions (20°F evaporation, R134a). This ultra-compact unit is one of the industry’s smallest commercially-viable refrigeration compressors, designed for light-duty applications including desktop ice makers, compact beverage coolers, medical/laboratory sample freezers, and portable marine cooling systems.
Remarkable Compactness:
Weight: Only 19 lbs (8.6 kg)
Displacement: 5.588 cc (tiny piston chamber requiring precision manufacturing)
Oil Charge: 243 cc (barely enough for motor cooling)
Locked-Rotor Amps: 28 A (relatively low for safe 115 V circuit use)
Rated Load Amps: 2.9 A @ 115 V 60 Hz (draws less current than a desk lamp)
Capacity and Efficiency Profile:
Evaporating Temp.
Capacity BTU/h (W)
Input Watts
Power Factor
20°F (−6.7°C)
950 BTU/h (278 W)
230 W
1.21 W/W
25°F (−3.9°C)
1,230 BTU/h (360 W)
257 W
1.40 W/W
30°F (−1.1°C)
1,370 BTU/h (401 W)
274 W
1.46 W/W
Critical Limitation: The LST (Low-Start-Torque) RSIR motor is deliberately designed to minimize inrush current stress on small electrical circuits. However, never operate this compressor without refrigerant circulation, as the micro-displacement cannot provide adequate oil circulation for motor cooling without active refrigerant flow. Running dry for even 10 seconds risks motor winding insulation breakdown and bearing seizure.
Typical Installations:Countertop beverage coolers at gas stations (2–4°C setpoint), portable coolers for boats and RVs, laboratory equipment with temperature-sensitive components.
AKA9442EXD-R: 1/2 HP, 760 W Mid-Range R-22 and R-407C
The Tecumseh AKA9442EXD-R is a 1/2-horsepower, single-phase compressor rated for 760 W input power at ASHRAE conditions (20°F evaporation, R-22). This R-22 specialist bridges the gap between legacy CFC systems and modern HFC/HFO blends, making it particularly valuable for retrofit scenarios in regions where R-22 phase-out is gradual and drop-in R-407C migration is cost-justified.
R-22 vs. R-407C Power Characteristics:
The AKA9442EXD-R’s specification sheet documents 1,231 W refrigeration capacity @ 20°F evaporation on R-22 with 760 W input power, yielding a coefficient of performance (COP) of 1.62. When retrofitted to R-407C (a non-flammable synthetic blend approved as drop-in replacement for R-22), capacity typically increases by 5–10% while discharge temperature often remains within acceptable limits (usually 5–10°C lower than baseline R-22 operation).
Motor and Electrical Specs:
Motor Type: CSR (Capacitor-Start/Run) with HST winding
Locked-Rotor Amps: 31 A (moderate; 1/3 that of larger models)
Rated Load Amps: 4 A @ 60 Hz (very economical)
Max Continuous Current: 6.64 A (allows smaller circuit breakers)
Displacement: 15.634 cc (mid-range piston volume)
Application Sweet Spot:Deli display cases, pharmacy refrigerators, small ice makers, walk-in coolers 8–15 m³ (280–530 cu ft). The 0°F to 50°F (−17.8°C to 10°C) evaporating range covers both chilled fresh-food applications and moderately frozen goods.
AKA4476YXA-R: 3/4 HP, 1,070–1,111 W High-Temperature Retail Cooler
The Tecumseh AKA4476YXA-R is a 3/4-horsepower, single-phase compressor consuming 1,070–1,111 W input power across R-134a and R-513A refrigerants at 45°F evaporation (high back-pressure rating). This model is optimized for supermarket produce displays, dairy coolers, and retail beverage cases operating near 2–8°C (35–46°F) evaporating temperature, where high COP and low discharge temperature are essential for compressor longevity and energy efficiency.
R-134a vs. R-513A Performance:
Refrigerant
Input Watts
Capacity (W)
COP (W/W)
Pressure Class
R-134a
1,070 W
2,250 W
2.10
Standard HBP
R-513A
1,111 W
2,265 W
2.04
Higher pressure (HFO blend)
Electrical Characteristics:
Locked-Rotor Amps: 58.8 A (requires motor-protection relay and hard-start kit in marginal voltage conditions)
Rated Load Amps: 11.3 A @ 115 V 60 Hz (moderate continuous draw)
Displacement: 22.599 cc (larger than 1/2 HP models, smaller than 1 HP units)
Why High-Temperature Application? The 20°F to 55°F (−6.7°C to 12.8°C) evaporating range places this compressor in the HBP (High Back-Pressure) classification, meaning suction pressures remain elevated even at light loads, protecting the motor winding from low-temperature cooling inadequacy. This design philosophy prioritizes reliability at warm evaporating temperatures over capacity at low temperatures.
Typical Installations:Supermarket dairy sections, produce rooms, beverage coolers, medication storage (pharmacies), bakery cold cases. The high efficiency (COP ≈ 2.0) translates to lower energy bills compared to older R-22 compressors operating in equivalent service.
AWG5524EXN-S: 2 HP, 1,650–2,480 W Dual-Voltage Large-Displacement R-22
The Tecumseh AWG5524EXN-S is a 2-horsepower, single-phase (despite the three-phase-like capacity) compressor with input power ranging from 1,650 W (light load) to 2,480 W (full load) at varying condensing temperatures. This large-displacement unit (43.1 cc) ranks among Tecumseh’s largest reciprocating compressors, delivering approximately 7,091 W (24,200 BTU/h) refrigeration capacity on R-22 at full-load conditions.
Power Profile Across Operating Envelope (230 V single-phase, R-22):
Evaporating Temp.
Condensing Temp. 100°F
Condensing Temp. 110°F
Condensing Temp. 120°F
0°F
1,100 W input
1,070 W input
—
10°F
1,210 W input
1,190 W input
1,170 W input
20°F
1,520 W input
1,560 W input
1,600 W input
Motor and Electrical Specifications:
Motor Type: PSC (Permanent-Split-Capacitor) with LST (Low-Start-Torque)
Locked-Rotor Amps: 60 A (substantial; demands heavy-duty electrical infrastructure)
Rated Load Amps: 11 A @ 60 Hz (continuous draw; requires 15 A minimum breaker)
Max Continuous Current: 18.3 A (absolute maximum permissible)
Displacement: 43.1 cc (nearly twice that of 1 HP models)
LST Motor Advantage: Unlike HST (High-Start-Torque) designs used in smaller compressors, the AWG5524EXN’s LST motor intentionally reduces inrush-current stress on facility electrical switchgear, capacitors, and contactors. This soft-start characteristic is critical when retrofitting older air-conditioning systems where the existing electrical infrastructure is marginal.
Application Range:Large supermarket condensing units, commercial ice-cream machine rooms, warehouse-scale blast freezers, industrial process cooling, R-22 retrofit projects in high-tonnage systems. The −10°F to 55°F (−23.3°C to 12.8°C) evaporating range covers everything from low-temperature freezers to high-temperature AC conditioners, making this a true multi-temperature workhorse.
AKA4460YXD: 1/2 HP, 889–890 W High-Temperature R-134a Unit
The Tecumseh AKA4460YXD is a 1/2-horsepower, single-phase compressor drawing 889–890 W input power at high-temperature rating (R-134a, 45°F evaporation). Despite its modest 1/2 HP electrical rating, it delivers approximately 6,250 BTU/h (1,830 W) refrigeration capacity, making it highly efficient for retail cooler and air-conditioning applications where warm evaporating temperatures (20°F to 55°F) are the norm.
High-Temperature (HT) Performance Profile (115 V single-phase, R-134a):
Evaporating Temp.
Input Watts
Capacity (W)
Efficiency (W/W)
20°F
890 W
1,830 W
2.06
30°F
891 W
2,100 W
2.36
40°F
893 W
2,350 W
2.63
50°F
895 W
2,600 W
2.90
Exceptional Efficiency at Warm Operating Points: Notice that as evaporating temperature rises (warmer operating conditions), input wattage stays nearly constant (~890–895 W) while capacity increases dramatically (1,830 W → 2,600 W). This represents an efficiency gain from 2.06 to 2.90 W/W—a hallmark of HBP/high-temperature design.
Electrical Characteristics:
Motor Type: CSIR (Capacitor-Start/Induction-Run) with HST
Locked-Rotor Amps: ~50 A (requires start component verification)
Rated Load Amps: 4–5 A @ 115 V 60 Hz (lightweight; suitable for 20 A circuits)
Displacement: Similar to AKA9442EXD (~15 cc class)
Complementary vs. Competing Role: Where the AKA9442EXD-R is R-22 legacy-focused, the AKA4460YXD is R-134a modern-focused. Both offer 1/2 HP rating and similar electrical profiles, but the AKA4460YXD’s warm evaporating envelope makes it the choice for air-conditioning condensing units and warm-weather cooler applications, while AKA9442EXD-R excels at chilled/frozen food storage.
Comparative Wattage and Efficiency Analysis
Power-to-Capacity Ratio (Input Watts vs. Refrigeration Watts)
To understand compressor efficiency relative to cooling output, the power-to-capacity ratio (also called COP or W/W coefficient) reveals which models deliver the most cooling per watt of electrical input:
Model
HP
Input Watts
Cooling Watts
W/W Ratio
Efficiency Ranking
AKA4460YXD
1/2
890
1,830–2,600
2.06–2.90
Excellent (HT-optimized)
AKA4476YXA-R
3/4
1,070
2,250
2.10
Excellent (HT-optimized)
AWG5524EXN-S
2
1,650–2,480
7,091
2.86 (avg)
Very Good
AKA9438ZXA
1/2
756
1,099
1.45
Good (CBP-rated)
AKA9442EXD-R
1/2
760
1,231
1.62
Good
AZA0395YXA
1/9
230
278
1.21
Fair (micro-sized)
AVA7524ZXT
3
3,490–4,000
6,973
1.74–1.99
Good
AWA2460ZXT
1.5
1,552–1,686
1,758
1.04–1.13
Fair (LT-rated; high pressure)
AHA2445AXD
1
1,225
1,289
1.05
Fair (legacy; low efficiency)
Key Insight:High-temperature (HT) models (AKA4460YXD, AKA4476YXA-R) deliver 2.0–2.9 W/W efficiency because warm evaporating temperatures reduce compression pressure ratios, allowing smaller volumes of gas to do more cooling work. Conversely, low-temperature (LT) models like AWA2460ZXT and AHA2445AXD struggle to exceed 1.1 W/W because extreme temperature differentials force large compression ratios with inherent inefficiency.
Refrigerant Selection and Wattage Impact
How Refrigerant Changes Input Power Requirements
The same compressor model can consume different input wattage depending on refrigerant choice. The AVA7524ZXT at 20°F evaporation is a perfect case study:
Refrigerant
Input Watts
Vs. R404A
Discharge Temp.
Pressure Ratio
R404A
4,000 W
Baseline (highest)
95°C (typical)
8.5:1
R449A
3,622 W
−9.4%
85°C (lower)
8.1:1
R448A
3,622 W
−9.4%
85°C (lower)
8.1:1
R452A
3,772 W
−5.7%
88°C
8.3:1
R407A
3,490 W
−12.8%
78°C (lowest)
7.9:1
R407A is the most efficient (3,490 W input) because it has a lower volumetric expansion ratio and inherently lower discharge temperatures. However, R407A is being phased down in favor of low-GWP blends like R448A and R452A, which offer 10–15°C lower discharge temperatures compared to baseline R404A while maintaining similar electrical input (within ±10%).
Installation, Electrical Integration, and Safety Guidelines
Matching Electrical Infrastructure to Compressor Power Draw
A critical installation error is undersizing circuit protection or motor starters relative to compressor inrush current. Example scenario:
Site Condition: Installation of AKA9438ZXA (1/2 HP, 756 W input) into a facility with existing 15 A circuit breaker.
Problem:Locked-rotor amps = 58.8 A. The motor starting relay must energize the compressor, causing inrush current of 58.8 A for ~200 ms. A 15 A breaker trips immediately; a 20 A breaker may nuisance-trip if voltage sags during startup.
Solution: Install hard-start kit (start capacitor 30–45 µF + potential relay) to reduce effective locked-rotor current to 30–40 A, allowing a 20 A breaker to handle the inrush safely.
Three-Phase vs. Single-Phase Considerations
Three-Phase Models (AVA7524ZXT, AWA2460ZXT):
Advantage: Much lower inrush current per phase (typically 1/3 of single-phase equivalent)
Disadvantage: Requires three-phase electrical service; facility must have three separate 120° phase waveforms
Advantage: 115 V or 208–230 V single-phase service available at nearly every site
Disadvantage: High inrush current (50–60 A); requires robust start components and voltage-stable circuits
Typical Sites: Retail stores, restaurants, small convenience shops
Voltage Sensitivity: All compressors are sensitive to ±10% voltage variation. A 115 V compressor operating at only 103.5 V (10% sag) experiences reduced motor torque, slower startup, and risk of thermal overload. Facilities with chronic voltage sag must install voltage-stabilizing transformers or power-factor correction equipment.
Complete Tecumseh compressor technical data: exact horsepower (1/9 HP to 3 HP), input watts (230 W to 4,000 W), R404A R134a capacities, and application guide for every model.
Tecumseh commercial compressors range from 1/9 HP (230 W) to 3 HP (4,000 W), delivering refrigeration capacities from 278 W to 6,973 W across R404A, R134a, and legacy refrigerants. This complete technical guide provides exact horsepower, input wattage, evaporating ranges, and application types for all ten major models used in supermarkets, walk-ins, and retail coolers.
Copeland ZB50KCE Scroll Compressor Nameplate: How to Read the Label and Choose the Right Polyester Oil
The photo shows the damaged nameplate of a Copeland ZB50KCE scroll compressor, factory‑charged with polyester (POE) oil for medium‑temperature refrigeration. Correctly interpreting this label helps technicians confirm oil, power, voltage and safety limits during service or replacement.
Compressor identification
The model belongs to the Copeland ZB series, used in commercial cold rooms and process cooling for refrigerants such as R404A, R134a and R22 alternatives. Depending on voltage code (TFD‑551, TFD‑950, etc.), it is sold as a 7 hp medium‑temperature compressor with around 11.9 kW nominal capacity.
Model code example: ZB50KCE‑TFD‑551 or ZB50KCE‑TFD‑950.
Technology: Hermetic scroll, part of the Summit series designed for higher seasonal efficiency.
Polyester oil (POE) on the label
The upper part of the label still shows POLYESTER OIL, confirming that the compressor is charged with POE lubricant. Catalogues list oil charges of about 2.6–2.7 l using approved POE types such as RL32‑3MAF or Mobil EAL Arctic 22 CC, depending on the variant.
POE oil absorbs moisture quickly, so systems must be evacuated deeply and fitted with quality filter‑driers.
Only compatible POE grades should be added; mixing with mineral or alkylbenzene oil is not permitted.
Technical data with hp and W
The following table compiles typical data for a Copeland ZB50KCE‑TFD‑551 running as a medium‑temperature refrigeration compressor; values may vary slightly by refrigerant and exact model.
Parameter
Typical value for ZB50KCE*
Nominal power
7 hp
Nominal capacity
11.9 kW cooling (≈11 900 W)
Electrical power input
≈7.5–7.9 kW depending on conditions
Displacement
19.8 m³/h
Supply voltage
380–420 V/3/50 Hz and 460 V/3/60 Hz (TFD code)
Maximum operating current
14.6 A
Locked‑rotor current
≈100 A
Oil type
POE (e.g. RL32‑3MAF)
Oil quantity
2.6–2.7 l
Sound level
≈64 dBA at 1 m
Net weight
≈59 kg (TFD‑551)
*Always confirm with the exact data sheet for your compressor code.
Voltage and operating limits on the sticker
On the lower part of the photographed label, remnants of “Volt 1 380 … Volt 2 460” can be identified, matching the dual‑voltage three‑phase motor used in TFD models. Another line mentions maximum current around 14.6 A, which is the value used to size breakers, contactors and cables.
The TFD motor code indicates 380–420 V/3/50 Hz and 460 V/3/60 Hz with internal motor protection.
Respecting these limits and using proper overload protection prevents overheating and nuisance trips in commercial installations.
Practical maintenance notes
For technicians such as those in Mbsmgroup and Mbsm.pro, a faded nameplate is common on older units, but the combination of model code and official catalogue restores all critical information. Creating a new service label with hp, kW, voltage, POE oil type and charge simplifies future troubleshooting and reduces the risk of mistakes during oil changes or retrofits.
When replacing or topping up oil, always isolate the compressor, recover refrigerant and work under clean, dry conditions.
If in doubt about capacity or application limits, refer to the Copeland ZB range catalogue and selection software before approving a replacement.
Refrigerants, Standing, Suction and Discharge Pressures for Modern HVAC Systems
Category: Refrigeration
written by www.mbsmpro.com | January 8, 2026
Guide to Common Refrigerants: Standing, Suction and Discharge Pressures for Modern HVAC Systems
Refrigeration technicians today work with a mix of legacy and new-generation refrigerants, each with its own safe pressure range and boiling temperature. Understanding these values is essential for accurate diagnostics, safe charging and long compressor life in air‑conditioning and commercial refrigeration.
Key role of pressure charts
Pressure–temperature charts and standing/suction/discharge tables give technicians a fast reference for what a system “should” be doing at a given ambient or evaporating temperature. Using wrong reference values can lead to over‑charging, overheating, liquid slugging or misdiagnosis of a healthy system as faulty.
Overview of common refrigerants
The image groups the most used refrigerants in residential and light commercial systems: R22, R134a, R600a, R32, R290, R407C, R404A, R410A and R417 (R417A). Each gas has a typical standing pressure (static pressure at rest), an evaporating suction pressure, a condensing discharge pressure and a characteristic boiling point at atmospheric pressure.
Typical pressure ranges from the chart
The following table summarises the indicative values shown in the chart (all pressures are approximate, for normally loaded systems at typical comfort‑cooling conditions).
Indicative pressures and boiling points
Refrigerant
Approx. standing pressure
Approx. suction pressure
Approx. discharge pressure
Boiling point (°C)
Typical replacement for
R22
150–155 psi / 1034–1069 kPa
60–70 psi / 413–483 kPa
250–300 psi / 1724–2069 kPa
−40.8 °C
R11 / legacy R22 AC
R134a
80–95 psi / 552–655 kPa
12–15 psi / 83–103 kPa
~150 psi / 1034 kPa
−26.2 °C
R12 in domestic & auto
R600a
40–50 psi / 276–345 kPa
≈0–1 psi / 0–7 kPa
~150 psi / 1034 kPa
−11.7 °C
Low‑charge fridges, R12
R32
240–245 psi / 1655–1689 kPa
110–115 psi / 758–793 kPa
175–375 psi / 1207–2586 kPa
−52.0 °C
High‑efficiency R410A/R22
R290
125–130 psi / 862–896 kPa
65–70 psi / 448–483 kPa
275–300 psi / 1896–2069 kPa
−42.1 °C
R22 in some systems
R407C
180–185 psi / 1241–1276 kPa
75–80 psi / 517–552 kPa
275–300 psi / 1896–2069 kPa
−45.0 °C (bubble)
R22 retrofits
R404A
180–185 psi / 1241–1276 kPa
80–90 psi / 552–621 kPa
275–300 psi / 1896–2069 kPa
−46.2 °C
R502 low‑temp systems
R410A
225–230 psi / 1551–1586 kPa
120–130 psi / 828–896 kPa
450–500 psi / 3103–3447 kPa
−51.4 °C
Modern R22 AC
R417A
~140 psi / 965 kPa standing
~65 psi / 448 kPa suction
~261 psi / 1796 kPa discharge
−39.0 °C
R22 service blend
These figures are not universal “set‑points”, but practical targets that help technicians decide whether a system is under‑charged, over‑charged or suffering airflow or mechanical problems.
Safety, cylinder colours and replacements
Many countries use conventional cylinder colour codes to identify refrigerants quickly on site, although some regions are migrating to neutral colours with clear labelling. Hydrocarbons such as R290 and R600a are flammable, so working pressures must always be combined with strict leak‑prevention, ventilation and ignition‑control procedures.
When phasing out ozone‑depleting R22, blends like R407C or R417A are often used in retrofit projects, while new high‑efficiency equipment typically relies on R410A or R32 with different design pressures. Comparing the standing and operating pressures during commissioning helps ensure that a replacement refrigerant is compatible with existing components such as compressors, valves and heat‑exchangers.
Practical use for technicians and trainers
Technicians can laminate similar tables and keep them in the toolbox or on the workshop wall as a quick‑reference during charging and troubleshooting.
Training centres and HVAC content creators like Mbsmgroup and Mbsm.pro can turn these values into interactive quizzes, infographics or mobile‑friendly charts for students and new technicians.
