Installation Mechanical
RTAF-SVX001K-EN
43
Low Evaporator Refrigerant Cutout and
Glycol Requirements
The tables below show the low evaporator temperature
cutout for different glycol levels. Additional glycol beyond
what is required for freeze protection will adversely effect
unit performance. The unit efficiency will be reduced and
the saturated evaporator temperature will be reduced. For
some operating conditions this effect can be significant.
Always use the applied actual percent glycol to establish
the low refrigerant cutout and low water temperature
cutout setpoints.
Note:
Tables below should not be interpreted as
suggesting operating ability or performance
characteristics at all tabulated glycol percentages.
Full unit simulation is required for proper
prediction of unit performance for specific
operating conditions. For information on specific
conditions, contact Trane product support.
Table 18. Ethylene glycol — low evaporator refrigerant temperature cutout (LERTC) and low water temperature cutout
(LWTC)
Unit Sizes 115 to 270 tons
Unit Sizes 280 to 520 tons
Glycol
Percentage
(%)
Solution
Freeze Point
(°F)
Minimum
Recommended
LERTC (°F)
Minimum
Recommended
LWTC (°F)
Glycol
Percentage
(%)
Solution
Freeze Point
(°F)
Minimum
Recommended
LERTC (°F)
Minimum
Recommended
LWTC (°F)
0
32.0
28.6
35.0
0
32.0
32.0
37.0
2
31.0
27.6
34.0
2
31.0
29.5
36.0
4
29.7
26.3
32.7
4
29.7
28.2
34.7
5
29.0
25.6
32.0
5
29.0
27.5
34.0
6
28.3
24.9
31.3
6
28.3
26.8
33.3
8
26.9
23.5
29.9
8
26.9
25.4
31.9
10
25.5
22.1
28.5
10
25.5
24.0
30.5
12
23.9
20.5
26.9
12
23.9
22.4
28.9
14
22.3
18.9
25.3
14
22.3
20.8
27.3
15
21.5
18.1
24.5
15
21.5
20.0
26.5
16
20.6
17.2
23.6
16
20.6
19.1
25.6
18
18.7
15.3
21.7
18
18.7
17.2
23.7
20
16.8
13.4
19.8
20
16.8
15.3
21.8
22
14.7
11.3
17.7
22
14.7
13.2
19.7
24
12.5
9.1
15.5
24
12.5
11.0
17.5
25
11.4
8.0
14.4
25
11.4
9.9
16.4
26
10.2
6.8
13.2
26
10.2
8.7
15.2
28
7.7
4.3
10.7
28
7.7
6.2
12.7
30
5.1
1.7
8.1
30
5.1
3.6
10.1
32
2.3
-1.1
5.3
32
2.3
0.8
7.3
34
-0.7
-4.1
5.0
34
-0.7
-2.2
5.0
35
-2.3
-5.0
5.0
35
-2.3
-3.8
5.0
36
-3.9
-5.0
5.0
36
-3.9
-5.0
5.0
38
-7.3
-5.0
5.0
38
-7.3
-5.0
5.0
40
-10.8
-5.0
5.0
40
-10.8
-5.0
5.0
42
-14.6
-5.0
5.0
42
-14.6
-5.0
5.0
44
-18.6
-5.0
5.0
44
-18.6
-5.0
5.0
45
-20.7
-5.0
5.0
45
-20.7
-5.0
5.0
46
-22.9
-5.0
5.0
46
-22.9
-5.0
5.0
48
-27.3
-5.0
5.0
48
-27.3
-5.0
5.0
50
-32.1
-5.0
5.0
50
-32.1
-5.0
5.0
