R-421A PT Chart

R-421A saturation pressure, −40 to 150 °F−40 to 65 °C. Used in R-22 A/C retrofits (Choice R421A).

How to use ↓

Safety class A1Zeotropic blendGlide 7.63 °F at 40 °F evapGlide 4.24 K at 4.4 °C evap

PT lookup

Step 1 Refrigerant

Step 2 I know the

Temperature Pressure

Step 3 Temperature

°F°C

Type a temperature to see the saturation pressure.

R-421A pressure temperature table

Liquid = bubble (subcooling). Vapor = dew (superheat). Below 0 psig: inches of mercury vacuum. Highlighted: 40 °F and 100 °F.Liquid = bubble (subcooling). Vapor = dew (superheat). Negative kPa = vacuum. Highlighted: 4 °C and 38 °C.

R-421A saturation pressure by temperature, °F and psig (vacuum in inches of mercury)
°F	Liquid bubble, psig	Vapor dew, psig
-40	0.5	6.1 inHg
-39	0.9	5.5 inHg
-38	1.3	4.8 inHg
-37	1.7	4.1 inHg
-36	2.1	3.3 inHg
-35	2.5	2.6 inHg
-34	3.0	1.8 inHg
-33	3.4	1.1 inHg
-32	3.9	0.3 inHg
-31	4.4	0.3
-30	4.8	0.7
-29	5.3	1.1
-28	5.8	1.5
-27	6.3	1.9
-26	6.8	2.4
-25	7.4	2.8
-24	7.9	3.3
-23	8.4	3.7
-22	9.0	4.2
-21	9.6	4.7
-20	10.1	5.2
-19	10.7	5.7
-18	11.3	6.2
-17	11.9	6.7
-16	12.5	7.3
-15	13.2	7.8
-14	13.8	8.4
-13	14.4	8.9
-12	15.1	9.5
-11	15.8	10.1
-10	16.5	10.7
-9	17.2	11.3
-8	17.9	11.9
-7	18.6	12.6
-6	19.3	13.2
-5	20.1	13.9
-4	20.8	14.5
-3	21.6	15.2
-2	22.4	15.9
-1	23.2	16.6
0	24.0	17.3
1	24.8	18.1
2	25.6	18.8
3	26.5	19.6
4	27.4	20.3
5	28.2	21.1
6	29.1	21.9
7	30.0	22.7
8	30.9	23.6
9	31.9	24.4
10	32.8	25.2
11	33.8	26.1
12	34.8	27.0
13	35.8	27.9
14	36.8	28.8
15	37.8	29.7
16	38.8	30.7
17	39.9	31.6
18	40.9	32.6
19	42.0	33.6
20	43.1	34.6
21	44.2	35.6
22	45.4	36.6
23	46.5	37.7
24	47.7	38.7
25	48.9	39.8
26	50.1	40.9
27	51.3	42.0
28	52.5	43.2
29	53.8	44.3
30	55.0	45.5
31	56.3	46.7
32	57.6	47.9
33	59.0	49.1
34	60.3	50.3
35	61.7	51.6
36	63.0	52.8
37	64.4	54.1
38	65.8	55.4
39	67.3	56.8
40	68.7	58.1
41	70.2	59.5
42	71.7	60.9
43	73.2	62.3
44	74.7	63.7
45	76.3	65.2
46	77.8	66.6
47	79.4	68.1
48	81.1	69.6
49	82.7	71.1
50	84.3	72.7
51	86.0	74.3
52	87.7	75.9
53	89.4	77.5
54	91.2	79.1
55	92.9	80.8
56	94.7	82.4
57	96.5	84.1
58	98.3	85.9
59	100.2	87.6
60	102.0	89.4
61	103.9	91.2
62	105.8	93.0
63	107.8	94.8
64	109.7	96.7
65	111.7	98.5
66	113.7	100.5
67	115.8	102.4
68	117.8	104.3
69	119.9	106.3
70	122.0	108.3
71	124.1	110.4
72	126.3	112.4
73	128.5	114.5
74	130.7	116.6
75	132.9	118.7
76	135.2	120.9
77	137.4	123.1
78	139.7	125.3
79	142.1	127.5
80	144.4	129.8
81	146.8	132.1
82	149.2	134.4
83	151.7	136.7
84	154.1	139.1
85	156.6	141.5
86	159.1	143.9
87	161.7	146.4
88	164.3	148.9
89	166.9	151.4
90	169.5	153.9
91	172.1	156.5
92	174.8	159.1
93	177.5	161.7
94	180.3	164.4
95	183.1	167.1
96	185.9	169.8
97	188.7	172.5
98	191.6	175.3
99	194.4	178.1
100	197.4	181.0
101	200.3	183.9
102	203.3	186.8
103	206.3	189.7
104	209.4	192.7
105	212.4	195.7
106	215.5	198.7
107	218.7	201.8
108	221.8	204.9
109	225.0	208.0
110	228.3	211.2
111	231.5	214.4
112	234.8	217.7
113	238.2	220.9
114	241.5	224.2
115	244.9	227.6
116	248.4	231.0
117	251.8	234.4
118	255.3	237.8
119	258.9	241.3
120	262.4	244.9
121	266.0	248.4
122	269.7	252.0
123	273.4	255.7
124	277.1	259.3
125	280.8	263.1
126	284.6	266.8
127	288.4	270.6
128	292.3	274.4
129	296.1	278.3
130	300.1	282.2
131	304.0	286.2
132	308.0	290.2
133	312.1	294.2
134	316.2	298.3
135	320.3	302.4
136	324.4	306.6
137	328.6	310.8
138	332.9	315.0
139	337.1	319.3
140	341.5	323.6
141	345.8	328.0
142	350.2	332.4
143	354.6	336.9
144	359.1	341.4
145	363.6	346.0
146	368.2	350.6
147	372.8	355.2
148	377.4	359.9
149	382.1	364.7
150	386.9	369.5

R-421A saturation pressure by temperature, °C and kPa (negative = vacuum)
°C	Liquid bubble, kPa	Vapor dew, kPa
-40	3.3	-20.8
-39	8.3	-16.6
-38	13.4	-12.3
-37	18.8	-7.8
-36	24.3	-3.1
-35	30.1	1.8
-34	36.0	6.8
-33	42.2	12.1
-32	48.6	17.5
-31	55.2	23.2
-30	62.0	29.0
-29	69.0	35.1
-28	76.3	41.4
-27	83.8	47.9
-26	91.6	54.7
-25	99.6	61.6
-24	107.9	68.9
-23	116.4	76.3
-22	125.2	84.1
-21	134.3	92.0
-20	143.6	100.3
-19	153.2	108.8
-18	163.1	117.6
-17	173.3	126.6
-16	183.8	136.0
-15	194.6	145.7
-14	205.8	155.6
-13	217.2	165.9
-12	229.0	176.4
-11	241.0	187.3
-10	253.5	198.5
-9	266.2	210.1
-8	279.3	222.0
-7	292.8	234.2
-6	306.6	246.8
-5	320.8	259.7
-4	335.3	273.0
-3	350.3	286.7
-2	365.6	300.7
-1	381.3	315.2
0	397.4	330.0
1	413.9	345.2
2	430.8	360.8
3	448.1	376.8
4	465.8	393.3
5	484.0	410.2
6	502.6	427.5
7	521.6	445.2
8	541.1	463.4
9	561.1	482.1
10	581.5	501.2
11	602.3	520.8
12	623.7	540.8
13	645.5	561.4
14	667.8	582.4
15	690.7	604.0
16	714.0	626.0
17	737.8	648.5
18	762.1	671.6
19	787.0	695.2
20	812.4	719.4
21	838.4	744.1
22	864.8	769.3
23	891.9	795.1
24	919.5	821.5
25	947.6	848.5
26	976.4	876.1
27	1005.7	904.2
28	1035.6	933.0
29	1066.1	962.3
30	1097.2	992.3
31	1129.0	1022.9
32	1161.3	1054.2
33	1194.3	1086.1
34	1227.9	1118.7
35	1262.2	1151.9
36	1297.1	1185.9
37	1332.7	1220.5
38	1368.9	1255.8
39	1405.8	1291.8
40	1443.5	1328.5
41	1481.8	1366.0
42	1520.8	1404.2
43	1560.5	1443.1
44	1601.0	1482.8
45	1642.2	1523.3
46	1684.1	1564.6
47	1726.8	1606.6
48	1770.2	1649.5
49	1814.4	1693.2
50	1859.4	1737.7
51	1905.1	1783.0
52	1951.7	1829.2
53	1999.1	1876.3
54	2047.3	1924.2
55	2096.3	1973.1
56	2146.2	2022.8
57	2196.9	2073.5
58	2248.5	2125.2
59	2300.9	2177.7
60	2354.2	2231.3
61	2408.5	2285.9
62	2463.6	2341.4
63	2519.7	2398.0
64	2576.7	2455.7
65	2634.6	2514.4

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R-421A PT Chart

°F / psig · Safety class A1 · Zeotropic blend

refrigerantptchart.com

°F	Liquid	Vapor
-40	0.5	6.1"
-39	0.9	5.5"
-38	1.3	4.8"
-37	1.7	4.1"
-36	2.1	3.3"
-35	2.5	2.6"
-34	3.0	1.8"
-33	3.4	1.1"
-32	3.9	0.3"
-31	4.4	0.3
-30	4.8	0.7
-29	5.3	1.1
-28	5.8	1.5
-27	6.3	1.9
-26	6.8	2.4
-25	7.4	2.8
-24	7.9	3.3
-23	8.4	3.7
-22	9.0	4.2
-21	9.6	4.7
-20	10.1	5.2
-19	10.7	5.7
-18	11.3	6.2
-17	11.9	6.7
-16	12.5	7.3
-15	13.2	7.8
-14	13.8	8.4
-13	14.4	8.9
-12	15.1	9.5
-11	15.8	10.1
-10	16.5	10.7
-9	17.2	11.3
-8	17.9	11.9
-7	18.6	12.6
-6	19.3	13.2
-5	20.1	13.9
-4	20.8	14.5
-3	21.6	15.2
-2	22.4	15.9
-1	23.2	16.6
0	24.0	17.3
1	24.8	18.1
2	25.6	18.8
3	26.5	19.6
4	27.4	20.3
5	28.2	21.1
6	29.1	21.9
7	30.0	22.7

°F	Liquid	Vapor
8	30.9	23.6
9	31.9	24.4
10	32.8	25.2
11	33.8	26.1
12	34.8	27.0
13	35.8	27.9
14	36.8	28.8
15	37.8	29.7
16	38.8	30.7
17	39.9	31.6
18	40.9	32.6
19	42.0	33.6
20	43.1	34.6
21	44.2	35.6
22	45.4	36.6
23	46.5	37.7
24	47.7	38.7
25	48.9	39.8
26	50.1	40.9
27	51.3	42.0
28	52.5	43.2
29	53.8	44.3
30	55.0	45.5
31	56.3	46.7
32	57.6	47.9
33	59.0	49.1
34	60.3	50.3
35	61.7	51.6
36	63.0	52.8
37	64.4	54.1
38	65.8	55.4
39	67.3	56.8
40	68.7	58.1
41	70.2	59.5
42	71.7	60.9
43	73.2	62.3
44	74.7	63.7
45	76.3	65.2
46	77.8	66.6
47	79.4	68.1
48	81.1	69.6
49	82.7	71.1
50	84.3	72.7
51	86.0	74.3
52	87.7	75.9
53	89.4	77.5
54	91.2	79.1
55	92.9	80.8

°F	Liquid	Vapor
56	94.7	82.4
57	96.5	84.1
58	98.3	85.9
59	100.2	87.6
60	102.0	89.4
61	103.9	91.2
62	105.8	93.0
63	107.8	94.8
64	109.7	96.7
65	111.7	98.5
66	113.7	100.5
67	115.8	102.4
68	117.8	104.3
69	119.9	106.3
70	122.0	108.3
71	124.1	110.4
72	126.3	112.4
73	128.5	114.5
74	130.7	116.6
75	132.9	118.7
76	135.2	120.9
77	137.4	123.1
78	139.7	125.3
79	142.1	127.5
80	144.4	129.8
81	146.8	132.1
82	149.2	134.4
83	151.7	136.7
84	154.1	139.1
85	156.6	141.5
86	159.1	143.9
87	161.7	146.4
88	164.3	148.9
89	166.9	151.4
90	169.5	153.9
91	172.1	156.5
92	174.8	159.1
93	177.5	161.7
94	180.3	164.4
95	183.1	167.1
96	185.9	169.8
97	188.7	172.5
98	191.6	175.3
99	194.4	178.1
100	197.4	181.0
101	200.3	183.9
102	203.3	186.8
103	206.3	189.7

°F	Liquid	Vapor
104	209.4	192.7
105	212.4	195.7
106	215.5	198.7
107	218.7	201.8
108	221.8	204.9
109	225.0	208.0
110	228.3	211.2
111	231.5	214.4
112	234.8	217.7
113	238.2	220.9
114	241.5	224.2
115	244.9	227.6
116	248.4	231.0
117	251.8	234.4
118	255.3	237.8
119	258.9	241.3
120	262.4	244.9
121	266.0	248.4
122	269.7	252.0
123	273.4	255.7
124	277.1	259.3
125	280.8	263.1
126	284.6	266.8
127	288.4	270.6
128	292.3	274.4
129	296.1	278.3
130	300.1	282.2
131	304.0	286.2
132	308.0	290.2
133	312.1	294.2
134	316.2	298.3
135	320.3	302.4
136	324.4	306.6
137	328.6	310.8
138	332.9	315.0
139	337.1	319.3
140	341.5	323.6
141	345.8	328.0
142	350.2	332.4
143	354.6	336.9
144	359.1	341.4
145	363.6	346.0
146	368.2	350.6
147	372.8	355.2
148	377.4	359.9
149	382.1	364.7
150	386.9	369.5

Liquid = bubble (use for subcooling). Vapor = dew (use for superheat). Italic " = inches of mercury vacuum. Bold rows: 40 °F and 100 °F. Reference only: always verify with the manufacturer’s data and your gauges.

R-421A PT Chart

°C / kPa (gauge) · Safety class A1 · Zeotropic blend

refrigerantptchart.com

°C	Liquid	Vapor
-40	3.3	-20.8
-39	8.3	-16.6
-38	13.4	-12.3
-37	18.8	-7.8
-36	24.3	-3.1
-35	30.1	1.8
-34	36.0	6.8
-33	42.2	12.1
-32	48.6	17.5
-31	55.2	23.2
-30	62.0	29.0
-29	69.0	35.1
-28	76.3	41.4
-27	83.8	47.9
-26	91.6	54.7
-25	99.6	61.6
-24	107.9	68.9
-23	116.4	76.3
-22	125.2	84.1
-21	134.3	92.0
-20	143.6	100.3
-19	153.2	108.8
-18	163.1	117.6
-17	173.3	126.6
-16	183.8	136.0
-15	194.6	145.7
-14	205.8	155.6
-13	217.2	165.9
-12	229.0	176.4
-11	241.0	187.3
-10	253.5	198.5
-9	266.2	210.1
-8	279.3	222.0
-7	292.8	234.2
-6	306.6	246.8
-5	320.8	259.7

°C	Liquid	Vapor
-4	335.3	273.0
-3	350.3	286.7
-2	365.6	300.7
-1	381.3	315.2
0	397.4	330.0
1	413.9	345.2
2	430.8	360.8
3	448.1	376.8
4	465.8	393.3
5	484.0	410.2
6	502.6	427.5
7	521.6	445.2
8	541.1	463.4
9	561.1	482.1
10	581.5	501.2
11	602.3	520.8
12	623.7	540.8
13	645.5	561.4
14	667.8	582.4
15	690.7	604.0
16	714.0	626.0
17	737.8	648.5
18	762.1	671.6
19	787.0	695.2
20	812.4	719.4
21	838.4	744.1
22	864.8	769.3
23	891.9	795.1
24	919.5	821.5
25	947.6	848.5
26	976.4	876.1
27	1005.7	904.2
28	1035.6	933.0
29	1066.1	962.3
30	1097.2	992.3
31	1129.0	1022.9

°C	Liquid	Vapor
32	1161.3	1054.2
33	1194.3	1086.1
34	1227.9	1118.7
35	1262.2	1151.9
36	1297.1	1185.9
37	1332.7	1220.5
38	1368.9	1255.8
39	1405.8	1291.8
40	1443.5	1328.5
41	1481.8	1366.0
42	1520.8	1404.2
43	1560.5	1443.1
44	1601.0	1482.8
45	1642.2	1523.3
46	1684.1	1564.6
47	1726.8	1606.6
48	1770.2	1649.5
49	1814.4	1693.2
50	1859.4	1737.7
51	1905.1	1783.0
52	1951.7	1829.2
53	1999.1	1876.3
54	2047.3	1924.2
55	2096.3	1973.1
56	2146.2	2022.8
57	2196.9	2073.5
58	2248.5	2125.2
59	2300.9	2177.7
60	2354.2	2231.3
61	2408.5	2285.9
62	2463.6	2341.4
63	2519.7	2398.0
64	2576.7	2455.7
65	2634.6	2514.4

Liquid = bubble (use for subcooling). Vapor = dew (use for superheat). Negative kPa = vacuum. Bold rows: 4 °C and 38 °C. Reference only: always verify with the manufacturer’s data and your gauges.

How to use

Choose Temperature or Pressure and type the number. The answer shows straight away.
Blends show two values: use vapor (dew) for superheat and liquid (bubble) for subcooling.
Tap °C · kPa for metric. Below 0 psig, pressure is in inches of mercury (inHg) vacuum.
Press Print pocket chart for a one-page chart (Letter or A4) for the van or the tool bag.

About this R-421A chart

This R-421A pressure temperature chart gives the saturation pressure for every degree, in psig with °F or kPa (gauge) with °C. As a blend, it has a liquid (bubble) and a vapor (dew) column. Below 0 psig the °F table shows inches of mercury (inHg) vacuum.

Source: supplier chart (A-Gas). Reference only: always verify with the manufacturer’s data and your gauges.

FAQ

What is the R-421A pressure at 40 °F?

58.1 psig vapor (dew) and 68.7 psig liquid (bubble) at saturation, from the table above.

What is the R-421A pressure at 100 °F?

181.0 psig vapor (dew) and 197.4 psig liquid (bubble) at saturation.

Which column do I use for superheat and subcooling?

Use vapor (dew) for superheat and liquid (bubble) for subcooling. R-421A has 7.63 °F of glide at a 40 °F evaporator, so the two columns differ.

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R-421A PT Chart

PT lookup

R-421A pressure temperature table

How to use

About this R-421A chart

FAQ

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