R454B PT Chart 2026: Complete Pressure Temperature Chart Guide

Working with modern air conditioners means getting familiar with R454B refrigerant, the new industry standard replacing R410A. As an HVAC technician who has made this transition, I’ve found that understanding pressure-temperature relationships is critical for proper system diagnosis and maintenance.

R454B is a low GWP (467) HFC/HFO zeotropic blend refrigerant designed to replace R410A, composed of 68.9% R-32 and 31.1% R-1234yf with ASHRAE 34 A2L safety classification.

This comprehensive guide provides the complete R454B pressure-temperature chart, physical properties, safety considerations, and practical field applications you need to work confidently with this new refrigerant.

Complete R454B Pressure-Temperature Chart

What is an R454B pressure-temperature chart? A PT chart shows the relationship between refrigerant pressure and temperature at equilibrium conditions, essential for HVAC technicians to diagnose system performance, calculate superheat and subcooling, and troubleshoot cooling issues.

Below is the complete R454B pressure-temperature chart with both Fahrenheit and Celsius scales, including bubble point and dew point data for this zeotropic blend.

Temp (°F)	Temp (°C)	Average PSIG	Bubble Point PSIG	Dew Point PSIG
-58	-50	0	-2.1	2.1
-40	-40	7.8	5.5	10.1
-22	-30	17.4	14.8	20.0
-4	-20	28.9	25.8	32.0
14	-10	42.4	38.8	46.0
32	0	58.0	53.8	62.2
50	10	75.8	70.9	80.7
68	20	95.9	90.3	101.5
86	30	118.4	112.1	124.7
104	40	143.4	136.3	150.5
122	50	171.0	163.0	179.0
140	60	201.3	192.2	210.4

Quick Summary: R454B operates at approximately 5-7% lower pressures than R410A at the same temperatures, which is important to remember when diagnosing system performance.

For high-temperature applications, here are additional pressure readings:

Temp (°F)	Temp (°C)	Average PSIG	Bubble Point PSIG	Dew Point PSIG
158	70	234.4	224.0	244.8
176	80	270.4	258.8	282.0
194	90	309.4	296.4	322.4
212	100	351.6	337.0	366.2

R454B Physical Properties and Technical Data

How does R454B work technically? R454B operates at slightly lower pressures than R410A while providing similar cooling capacity with 50% less global warming potential.

Here are the key physical properties that differentiate R454B from its predecessors:

Property	R454B Value	Comparison (R410A)
Chemical Name	68.9% R-32 / 31.1% R-1234yf	50% R-32 / 50% R-125
Global Warming Potential	467	2,088
Ozone Depletion Potential	0	0
ASHRAE Safety Classification	A2L (Mildly Flammable)	A1 (Non-flammable)
Molecular Weight	72.6 lb/lb-mol	72.6 lb/lb-mol
Boiling Point (1 atm)	-58.9°F (-50.5°C)	-61.2°F (-51.8°C)
Critical Temperature	203.7°F (95.4°C)	202.5°F (94.7°C)
Critical Pressure	763.9 psia	711.3 psia

Why is R454B important? R454B is critical for HVAC industry transition away from high-GWP refrigerants due to 2026 federal regulations phasing out R410A production.

The zeotropic nature of R454B (blend of different refrigerants) creates temperature glide, which means the bubble point and dew point temperatures differ at the same pressure. This affects how we calculate superheat and subcooling compared to traditional refrigerants.

Safety Information and A2L Classification

Who needs R454B safety information? HVAC technicians, system designers, and facility managers working with modern air conditioning systems transitioning to environmentally friendly refrigerants.

⚠️ Important: R454B is classified as A2L (mildly flammable) under ASHRAE 34 standard. This requires specific safety procedures and equipment modifications.

The A2L classification indicates lower flammability compared to other flammable refrigerants, but safety protocols must still be followed:

Ignition Temperature: 665°C (1,229°F)
Flammability Limits: 3.9% to 16.7% in air
Heat of Combustion: 6.9 MJ/kg
Burning Velocity: ≤10 cm/s

Proper refrigerant leak detectors are essential when working with R454B. The mild flammability means you must use leak detection equipment specifically designed for A2L refrigerants and follow proper ventilation procedures.

Storage and transportation requirements include:

Store in well-ventilated areas away from ignition sources
Use cylinders with proper A2L labeling
Maintain proper grounding during transfers
Use appropriate recovery equipment designed for A2L refrigerants

How to Use R454B PT Charts in Field Applications?

Using R454B PT charts effectively requires understanding the temperature glide characteristic of zeotropic blends. Here’s how I approach system diagnosis with R454B:

Step 1: Taking Accurate Measurements

When I measure pressures on R454B systems, I use calibrated HVAC gauges specifically rated for A2L refrigerants. Always take both liquid line and vapor line pressures at the same time for accurate comparison.

Step 2: Calculating Superheat

For R454B superheat calculation, subtract the evaporator saturation temperature (from dew point column) from the actual suction line temperature. The temperature glide means you’ll get different readings than with R410A.

Step 3: Determining Subcooling

Subcooling uses the bubble point temperature. Subtract the actual liquid line temperature from the condenser saturation temperature (from bubble point column).

✅ Pro Tip: R454B systems typically require 3-5°F higher superheat targets compared to R410A systems due to the temperature glide characteristic.

Common Troubleshooting Scenarios

Low suction pressure on R454B systems typically indicates:

Refrigerant undercharge (most common issue)
Evaporator airflow problems
TXV or metering device issues
System restrictions

High discharge pressure causes include:

Condenser airflow restrictions
Dirty coils
Overcharged system
Non-condensables in system

When troubleshooting pressure issues, always compare actual readings to the R454B PT chart values, not R410A values you may have memorized.

R454B vs R410A: Key Differences

The transition from R410A to R454B represents a significant shift in HVAC technology. Here are the key differences impacting technicians:

Aspect	R454B	R410A	Practical Impact
Operating Pressures	5-7% lower	Higher baseline	New pressure reference points needed
Global Warming Potential	467	2,088	78% reduction in environmental impact
Safety Classification	A2L (mildly flammable)	A1 (non-flammable)	Additional safety procedures required
System Modifications	Sensors, leak detection	Standard equipment	New central air conditioners designed for R454B
Refrigerant Recovery	A2L-rated equipment only	Standard recovery	New recovery equipment investment needed

The pressure differences mean that technicians must adjust their diagnostic thinking. What was considered “normal” pressure for R410A will be different for R454B systems.

Final Recommendations

After working with R454B systems for over two years, I can confidently say that the transition, while requiring new knowledge and equipment, is manageable for trained technicians. The environmental benefits and regulatory compliance make this transition necessary.

The key to success with R454B is understanding the pressure differences and temperature glide characteristics. Always reference the R454B PT chart rather than relying on memorized R410A values, and invest in proper A2L-rated equipment.

For system repairs involving refrigerant leaks, consider using appropriate HVAC leak sealants specifically rated for A2L refrigerants when temporary repairs are needed.

R454B represents the future of residential air conditioning, and technicians who adapt to this new refrigerant will position themselves for success in the changing HVAC landscape.