R-454B PT Chart: Pressure-Temperature Table + How to Use It

Reference saturation values, computed with CoolProp (R454B.mix mixture model) and cross-checked against the Honeywell Solstice 454B published PT chart and supplier charts — agreement is within about 1 psi across this range. Manufacturer charts round differently, so treat these as reference values and confirm against the chart on the jug or the equipment's charging chart when it matters.

Temp (F)	Bubble / Liquid (psig)	Dew / Vapor (psig)
-20	24.7	22.7
-10	34.5	32.0
0	45.9	42.9
10	59.3	55.7
20	74.8	70.6
30	92.7	87.8
40	113.2	107.5
50	136.4	129.9
60	162.7	155.3
70	192.3	183.9
80	225.4	216.0
90	262.3	251.9
100	303.3	291.9
110	348.6	336.3
120	398.6	385.5
130	453.6	440.0

Both columns are gauge pressure (psig) at saturation. A running system will not sit exactly on these numbers — operating pressures depend on load, airflow, and outdoor conditions. The chart tells you the saturation temperature that corresponds to a measured pressure; the diagnosis comes from comparing that to your measured line temperatures.

R-454B is a zeotropic blend of 68.9% R-32 and 31.1% R-1234yf by weight. The two components don't boil at the same temperature, so at any given pressure the blend starts boiling at one temperature (the bubble point) and finishes at a higher one (the dew point). That spread is the temperature glide — about 1.5 C (roughly 2.5-2.7 F) for R-454B at typical operating pressures, per the CoolProp mixture model and Honeywell's published data. Small compared to something like R-407C, but big enough that using the wrong column costs you 2-3 F of accuracy on every reading.

The rule, straight from Honeywell's Solstice 454B application guidance:

• Dew point column — vapor side. Use it with suction pressure for superheat and evaporator saturation temperature.
• Bubble point column — liquid side. Use it with liquid-line pressure for subcooling and condensing temperature.

A single-column R-454B chart or gauge scale is averaging the glide away. That's a built-in 1-1.5 F error on both superheat and subcooling before you've measured anything. With a blend, always work from a two-column chart or a gauge set with proper bubble/dew scales.

Same procedure as any refrigerant — the only change from R-410A habits is picking the right column.

Superheat (vapor side — dew column):

Superheat (F) = suction line temperature (F) − dew saturation temperature (F)

Example: suction gauge reads 130 psig. From the dew column, 130 psig is about 50 F saturation. Strap a probe on the suction line near the condensing unit and read 60 F. Superheat = 60 F − 50 F = 10 F.

Subcooling (liquid side — bubble column):

Subcooling (F) = bubble saturation temperature (F) − liquid line temperature (F)

Example: liquid-line gauge reads 349 psig. From the bubble column, that's about 110 F saturation. Liquid line measures 100 F at the service valve. Subcooling = 110 F − 100 F = 10 F.

Charging targets don't come from the PT chart — they come from the equipment. Charge TXV/EEV systems to the subcooling target on the data plate or charging chart; charge fixed-orifice systems to the manufacturer's target-superheat table for the measured indoor wet-bulb and outdoor dry-bulb. Those manufacturer tables are already built for R-454B on new equipment — the PT chart's job is converting your gauge reading into a saturation temperature you can trust.

R-454B was picked as the closest low-GWP match to R-410A, and the pressures show it. At the same saturation temperature, R-454B runs a few percent lower than R-410A — about 5% lower on the bubble side and 8-10% lower on the dew side (the glide splits the difference in R-410A's favor on the vapor column). You'll hear techs say it runs higher; the saturation data says otherwise.

Temp (F)	R-454B bubble (psig)	R-454B dew (psig)	R-410A (psig)
40	113.2	107.5	118.8
70	192.3	183.9	201.7
100	303.3	291.9	318.5
120	398.6	385.5	419.5

(R-410A saturation values from the same CoolProp property engine; R-410A's glide is under 0.5 F, so one column covers it.)

Practical upshot: your R-410A-class gauges and hoses handle the pressure fine, and a system that ran 418 psig head on R-410A will condense at similar temperatures near 400 psig on R-454B. Don't eyeball R-410A numbers from memory, though — an 8-10% suction-side gap reads like a low charge if you're mentally on the wrong chart. GWP is 466, about 78% below R-410A's 2,088, which is why it's replacing R-410A in new residential equipment under the AIM Act phasedown.

R-454B is ASHRAE Standard 34 class A2L — lower toxicity, mildly flammable, burning velocity 10 cm/s or less. It is hard to ignite and doesn't sustain a flame easily, but it is not an A1 like R-410A, and the work rules change:

• A2L-rated recovery machine, hoses, and leak detector. Standard R-410A recovery units aren't rated for flammable refrigerants. Never vent — EPA Section 608 recovery rules apply to R-454B like any other refrigerant.
• No ignition sources in the work zone. Flow nitrogen while brazing (good practice on any system, mandatory habit here), and check with your A2L detector before lighting a torch on a system that held charge.
• New equipment only. R-454B is not a drop-in for R-410A systems. A2L equipment is listed to UL 60335-2-40, with charge limits and, on some systems, refrigerant leak-detection sensors that drive the blower to dissipate a leak. Retrofitting an A2L into an A1-listed system violates the listing.
• Cylinders are marked. A2L jugs carry a red band on the shoulder flagging the flammability class, and they still ship with standard service threads.

None of this is exotic — it's the same discipline R-32 split systems have run on overseas for years. Get the A2L-rated tools, keep ignition sources out of the work zone, and the PT chart work is identical to what you already do.