R-1234yf PT Chart
Saturation pressure for R-1234yf from -40°F to 110°F. Look up a pressure or temperature, switch to metric, and check typical operating pressures.
By BrazeJobs Team · Updated
R-1234yf Lookup
Saturation Pressure
38.4 psig
Saturation Temp
39.6°F
Chart range: -40°F to 110°F. Enter vacuum as a negative pressure. Check R-1234yf superheat and subcooling
R-1234yf PT Chart
| Temp | Pressure |
|---|---|
| -40°F | 11.6 inHg vac |
| -35°F | 9.0 inHg vac |
| -30°F | 5.9 inHg vac |
| -25°F | 2.8 inHg vac |
| -20°F | 0.4 psig |
| -15°F | 2.3 psig |
| -10°F | 4.4 psig |
| -5°F | 6.7 psig |
| 0°F | 9.2 psig |
| 5°F | 11.9 psig |
| 10°F | 14.9 psig |
| 15°F | 18.1 psig |
| 20°F | 21.6 psig |
| 25°F | 25.4 psig |
| 30°F | 29.4 psig |
| 35°F | 33.8 psig |
| 40°F | 38.4 psig |
| 45°F | 43.4 psig |
| 50°F | 48.8 psig |
| 55°F | 54.5 psig |
| 60°F | 60.6 psig |
| 65°F | 67.0 psig |
| 70°F | 73.9 psig |
| 75°F | 81.2 psig |
| 80°F | 89.0 psig |
| 85°F | 97.2 psig |
| 90°F | 106.0 psig |
| 95°F | 115.0 psig |
| 100°F | 125.0 psig |
| 105°F | 135.0 psig |
| 110°F | 146.0 psig |
About R-1234yf
R-1234yf is a single-component HFO with a GWP of 4. It replaced R-134a in car and light truck AC and is now in most new vehicles. Its pressures are close to R-134a.
It is classed A2L, mildly flammable. As a single component it has no glide. It is also an ingredient in blends such as R-454B and R-448A. Hudson publishes R-1234yf data from -40°F to 110°F.
Car AC pressures move with engine speed, blower setting and outdoor temperature. A common test is engine at about 1,500 rpm, doors open, blower on high and AC at max, then comparing the readings with the vehicle maker’s chart for that ambient temperature. The PT chart tells you what the gauge pressure means in evaporator and condenser temperature.
- Car and light truck AC in most new vehicles
- Hybrid and electric vehicle AC and battery cooling
- Component of R-454B, R-448A and R-513A
R-1234yf Properties
Key facts for identifying R-1234yf and choosing tools, oil and replacements.
| Property | Value |
|---|---|
| Type | HFO |
| Composition | 100% 2,3,3,3-tetrafluoropropene |
| ASHRAE safety class | A2L |
| GWP (IPCC AR4) | 4 |
| Boiling point at 1 atm | -21.1°F |
| Critical temperature | 202.5°F |
| Oil | PAG or POE, as specified by the vehicle maker |
| Trade names | Opteon YF, Solstice yf |
| Replaces | R-134a |
| Replaced by | None |
Typical R-1234yf Operating Pressures
Suction pressure is the vapor (dew) pressure at the evaporator temperature; head pressure is the liquid (bubble) pressure at the condensing temperature. The temperatures are common design points, not charging targets.
| Condition | Evaporator | Suction | Condensing | Head |
|---|---|---|---|---|
| Car AC, about 80°F outdoor | 35°F | 33.8 psig | 110°F | 146.0 psig |
How to Read the R-1234yf PT Chart
The chart covers -40°F to 110°F. Pressures are gauge pressure (psig), the number your manifold shows; switch to °C and kPa above if you work in metric. At the cold end, R-1234yf saturates below atmospheric pressure, so those rows read in inches of mercury vacuum (inHg vac), the same as the vacuum scale on a compound gauge.
The chart has one pressure column because liquid and vapor share the same saturation pressure at each temperature. Use the same column for superheat (suction side) and subcooling (liquid side).
To read it, find the pressure on your gauge and read across to the saturation temperature, or start from a temperature and read the pressure. The lookup above interpolates between rows for you.
Superheat and Subcooling Formulas
The PT chart turns a gauge pressure into a saturation temperature. Compare that with a line temperature to get superheat or subcooling.
- Tsuction
- Suction line temperature near the outdoor unit or compressor, °F
- Tliquid
- Liquid line temperature leaving the condenser, °F
- Tsat
- Saturation temperature at the gauge pressure, °F
Gauge pressure (psig) is pressure above atmospheric. Below 0 psig, the chart shows vacuum in inches of mercury.
Worked Example: R-1234yf Superheat and Subcooling
Car AC, about 80°F outdoor: an R-1234yf system reads 33.8 psig suction with a 45°F suction line, and 146.0 psig on the liquid line with a 100°F liquid line.
- Saturation temperature at 33.8 psig: 35.0°F.
- Superheat: 45°F − 35.0°F = 10.0°F.
- Saturation temperature at 146.0 psig: 110.0°F.
- Subcooling: 110.0°F − 100°F = 10.0°F.
Is R-1234yf Being Phased Out?
R-1234yf is the standard refrigerant for new light vehicles in the US. With a GWP of 4, it is not affected by the HFC phasedown.
Service requires SAE J2843 certified recovery, recycling and recharging equipment with a refrigerant identifier. Its service ports differ from R-134a ports so the two cannot be mixed.
R-1234yf Field Tips
Practical points for working on R-1234yf systems, from the sources below.
Sources: Vehicle Service Pros: Moving from R-134a to R-1234yf, ASHRAE: Refrigerant designations and safety classes