HVAC Technical Support, AC Pressure Temperature Chart, AC Condensing Temperature

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To use the HVAC Technical Support AC Pressure Temperature Chart,

Turn unit on; monitor system running approximately 15 to 30 minutes. Take a reading of your refrigerant system pressure (PSIG).
Find the corresponding saturated pressure for your refrigerant.

Superheat (for units with fixed metering device): Compute the superheat by determining saturated suction temperature from Temperature Pressure Chart. Subtract from actual suction line temperature before compressor. The manufacturers recommended superheat is usually listed in the installation instructions on on the units rating plate. If it is not listed use 15 degrees of superheat as a default.

Subcooling (for units with Thermostatic Expansion Valve or TXV): Compute subcooling by determining saturated condensing temperature from Temperature Pressure Chart. Subtract from liquid temperature entering TXV. The manufactures recommended subcooling is usually listed on units rating plate. If it is not listed use 15 degrees of subcooling as a default.

PSIG	R-22	R-134A	R-410A	PSIG	R-22	R-134A	R-410A
0	-41	-15	-60	78	46	75	20
2	-37	-10	-58	80	48	76	21
4	-32	-5	-54	85	51	79	24
6	-28	-1	-50	90	54	82	26
8	-24	3	-46	95	56	85	29
10	-20	7	-42	100	59	88	32
12	-17	10	-39	105	62	90	34
14	-14	13	-36	110	64	93	36
16	-11	16	-33	115	67	96	39
18	-8	19	-30	120	69	98	41
20	-5	22	-28	125	72	100	43
22	-3	25	-26	130	74	103	45
24	0	27	-24	135	76	105	47
26	2	30	-20	140	78	107	49
28	5	32	-18	145	81	109	51
30	7	35	-16	150	83	112	53
32	9	37	-14	160	87	116	57
34	11	39	-12	170	91	120	60
36	13	41	-10	180	94	123	64
38	15	43	-8	190	98	127	67
40	17	45	-6	200	101	131	70
42	19	47	-4	210	105	134	73
44	21	49	-3	220	108	137	76
46	23	51	-2	225	110	139	78
48	24	52	0	235	113	142	80
50	26	54	1	245	116	145	83
52	28	56	3	255	119	148	85
54	29	57	4	265	121	151	88
56	31	59	6	275	124	153	90
58	32	60	7	285	127	155	92
60	34	62	8	295	130	158	95
62	35	64	10	305	133	161	97
64	37	65	11	325	137	167	101
66	38	66	13	355	144	173	108
68	40	68	14	375	148	177	112
70	41	69	15	405	155	182	118
72	42	71	16	500	173	202	134
74	44	72	17	600	N/A	N/A	149
76	45	73	19	700	N/A	N/A	159