HVAC · PT Chart

R-404A PT Chart

Pressure–temperature saturation chart for R-404A (provisional — verify before charging). Convert pressure to saturation temperature and back, or print the full table.

Convert

Gauge pressure

psig

Blend: use the dew value for suction (superheat) and the bubble value for liquid (subcooling).

R-404A saturation

58.3°F

Sat temp (dew)

58.3°F

Sat temp (bubble)

57.4°F

R-404A saturation table

psig at sea level · A1

Temp (°F)	Bubble (psig)	Dew (psig)
-40	5	3
-38	6.1	4.1
-36	7.1	5.1
-34	8.2	6.2
-32	9.2	7.2
-30	10.2	8.2
-28	11.3	9.3
-26	12.4	10.4
-24	13.5	11.5
-22	14.7	12.7
-20	16	14
-18	17.3	15.3
-16	18.7	16.7
-14	20.2	18.2
-12	21.7	19.7
-10	23.3	21.3
-8	25	23
-6	26.6	24.6
-4	28.4	26.4
-2	30.2	28.2
0	32	30
2	33.9	31.9
4	35.8	33.8
6	37.9	35.9
8	40	38
10	42.1	40.1
12	44.4	42.4
14	46.7	44.7
16	49.1	47.1
18	51.5	49.5
20	54	52
22	56.6	54.6
24	59.3	57.3
26	62.1	60.1
28	65	63
30	68	66
32	71.1	69.1
34	74.3	72.3
36	77.5	75.5
38	80.7	78.7
40	84	82
42	87.4	85.4
44	90.8	88.8
46	94.4	92.4
48	98.1	96.1
50	102	100
52	106.1	104.1
54	110.3	108.4
56	114.8	112.9
58	119.3	117.4
60	124	122
62	128.8	126.6
64	133.7	131.3
66	138.7	136.1
68	143.8	141
70	149	146
72	154.2	151.1
74	159.5	156.4
76	164.8	161.8
78	170.3	167.3
80	176	173
82	181.9	178.9
84	188	185
86	194.2	191.2
88	200.5	197.5
90	207	204
92	213.5	210.5
94	220.2	217.2
96	227	224
98	233.9	230.9
100	241	238
102	248.3	245.3
104	255.7	252.7
106	263.3	260.3
108	271.1	268.1
110	279	276
112	287.1	284.1
114	295.3	292.4
116	303.7	300.8
118	312.3	309.3
120	321	318
122	329.9	326.7
124	338.9	335.5
126	348.1	344.4
128	357.4	353.6
130	367	363
132	376.9	372.8
134	387	382.9
136	397.3	393.3
138	407.7	403.7
140	418	414

Bubble vs. dew — how to read a blend

R-404A is a refrigerant blend, so it boils and condenses across a small temperature range (glide of ~0.7 °F) rather than at a single point. The bubble line is where liquid starts to boil; the dew line is where the last vapor condenses. For charge checks: use the dew temperature for superheat on the suction line, and the bubble temperature for subcooling on the liquid line.

Frequently asked

What pressure should R-404A run at?

It depends on the saturation temperature you are targeting, not a single number. Read your gauge pressure, convert it to a saturation temperature with the chart above, then compare it to your line temperature for superheat or subcooling.

Does R-404A have temperature glide?

R-404A is a near-azeotrope with glide of ~0.7 °F. Use the dew (vapor) temperature for superheat on the suction line and the bubble (liquid) temperature for subcooling on the liquid line.

Is this R-404A PT chart accurate for charging?

Use it for field reference. This chart is interpolated from published manufacturer anchor points and is marked provisional — confirm against the manufacturer PT chart before final charging.

Sources & references

CoolProp — open-source thermophysical property library used to generate the saturation curves
EPA Section 608 — refrigerant handling and the venting prohibition
ASHRAE Handbook — Fundamentals — refrigerant and psychrometric property basis

Estimates for planning purposes only. Verify all results against the code edition adopted in your jurisdiction and with your Authority Having Jurisdiction (AHJ). This tool is not a substitute for a licensed HVAC contractor. See our methodology, sources, and code editions.