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R-134a Diagnostic Tool

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View R-134a NRE Explanation

R-134a Diagnostic Tool

All calculations use PSIA • Most gauges read PSIG (14.7 psi atmospheric)

Loading R-134a thermodynamic data...

Quick Load Realistic Scenarios

Suction Pressure
Suction Line Temp (°F)
Liquid Pressure
Liquid Line Temp (°F)
System Capacity (tons) — optional
Discharge Line Temp (°F) — optional
Return Air Wet Bulb (°F) — optional
Return Air Dry Bulb (°F) — optional
Ambient Condition

Session History & Running Average (0)

No diagnostics run yet.

Important Notes for R-134a

Azeotropic — no temperature glide (bubble = dew point).
Common in automotive AC and medium-temp refrigeration.
GWP = 1,430 (high — being phased down in many regions).
Requires POE oil in most new systems.

References & Data Sources

NIST Chemistry WebBook – R-134a Thermophysical Properties: https://webbook.nist.gov/chemistry/fluid/ (select R-134a)
Chemours / DuPont Freon 134a Thermodynamic Properties (NIST REFPROP validated)
Lemmon, E.W., Huber, M.L., McLinden, M.O. NIST Standard Reference Database 23: REFPROP, Version 10.0
Typical operation in automotive and commercial refrigeration applications

R-134a PT Chart

Temperature (°F)	Liquid psig	Vapor psig

Azeotropic (Liquid = Vapor pressures) • No glide
Typical field gauges: suction ~25–45 psig, liquid ~120–180 psig (medium temp)