![background image](http://html1.mh-extra.com/html/carrier/supra-750mt/supra-750mt_operation-and-service-manual_2563856078.webp)
4-21
62--611XX--20 (03/04)
4.19.4
Suction pressure transducer
Before installing a new suction pressure transducer it must be calibrated.
The calibration will not be performed if the run relay is energized. This prevents the operator from calibrating the
unit with the sensor in the system. The reading of the sensor must be at atmospheric pressure (0 psig or 14.7 psi).
If the sensor reading is greater than 20 psig (34.7 psi) or less than --6.7 psig (8 psi) it can not be calibrated. Once the
micro is calibrated, the display will readout the actual value.
a.
Turn power off and remove starter solenoid wire, then let unit fail to start. This will de-energize run relay.
b.
Connect wiring to new suction pressure transducer. Before installing suction pressure transducer into unit, display
the suction pressure via the unit status display. While the suction pressure is being displayed press
Enter Key
for 3 seconds, the display should read “0”. If display reads “0” install suction pressure transducer into unit.
Table 4-5 R-404A Temperature-Pressure chart
Temperature
Pressure
Temperature
Pressure
_
C
_
F
Psig Kg/cm
@
Bar
_
C
_
F
Psig Kg/cm
@
Bar
--40 --40
4.5
0.32
0.31
0
32
72.5
5.10
5.00
--37 --35
7.1
0.50
0.49
1
34
75.6
5.32
5.21
--34 --30
9.9
0.70
0.68
2
36
78.8
5.54
5.43
--32 --25
12.9
0.91
0.89
3
38
82.1
5.77
5.66
--29 --20
16.3
1.15
1.12
4
40
85.5
6.01
5.90
--28 --18
17.7
1.24
1.22
6
42
89.0
6.26
6.14
--27 --16
19.2
1.35
1.32
7
44
92.5
6.50
6.38
--26 --14
20.7
1.46
1.43
8
46
96.2
6.76
6.63
--24 --12
22.3
1.57
1.54
9
48
99.9
7.02
6.89
--23 --10
23.9
1.68
1.65
10
50
103.7
7.29
7.15
--22
--8
25.6
1.80
1.77
13
55
115.4
8.11
7.96
--21
--6
27.3
1.92
1.88
16
60
126.1
8.87
8.69
--20
--4
29.1
2.05
2.01
18
65
137.4
9.66
9.47
--19
--2
30.9
2.17
2.13
21
70
149.4
10.50 10.30
--18
0
32.8
2.31
2.26
24
75
162.1
11.40
11.18
--17
2
34.8
2.45
2.40
27
80
175.5
12.34 12.10
--16
4
36.8
2.59
2.54
29
85
189.6
13.33 13.07
--14
6
38.9
2.73
2.68
32
90
204.5
14.38 14.10
--13
8
41.1
2.89
2.83
35
95
220.2
15.48 15.18
--12
10
43.3
3.04
2.99
38
100 236.8
16.65 16.33
--11
12
45.6
3.21
3.14
41
105 254.2
17.87 17.53
--10
14
48.0
3.37
3.31
43
110 272.4
19.15 18.78
--9
16
50.4
3.54
3.47
46
115 291.6
20.50
20.11
--8
18
52.9
3.72
3.65
49
120 311.8
21.92 21.50
--7
20
55.5
3.90
3.83
52
125 332.9
23.41 22.95
--6
22
58.1
4.08
4.01
54
130 355.0
24.96 24.48
--4
24
60.9
4.28
4.20
57
135 378.1
26.58 26.07
--3
26
63.7
4.48
4.39
60
140 402.3
28.28 27.74
--2
28
66.5
4.68
4.59
63
145 4 27.6
30.06
29.48
--1
30
69.5
4.89
4.79
66
150 454.0
31.92 31.30