Startup (Cooling); Table 25 - R410A Pressure And Temperature Chart - Johnson Controls DSH024C Series Installation Operation & Maintenance

SECTION 2 – STARTUP AND OPERATION
• Liquid Line Subcooling = Saturation Temperature
(108.0°F) minus Liquid Line Temperature (95.0°)
= 13.0°F
Subcooling should be 10.0–14.0°F at design conditions.
TABLE 25 - R-410A PRESSURE AND TEMPERA-
TURE CHART
PSIG TEMP ˚F
0 -60
2 -58
4 -54
6 -50
8 -46
10 -42
12 -39
14 -36
16 -33
18 -30
20 -28
22 -26
24 -24
26 -20
28 -18
30 -16
32 -14
34 -12
36 -10
38 -8
40 -6
42 -4
44 -3
46 -2
48 0
50 1
52 3
54 4
56 6
58 7
60 8
62 10
64 11
66 13
68 14
70 15
72 16
74 17
76 19
40
PSIG TEMP ˚F
78 20
80 21
85 24
90 26
95 29
100 32
105 34
110 36
115 39
120 41
125 43
130 45
135 47
140 49
145 51
150 53
160 57
170 60
180 64
190 67
200 70
210 73
220 76
225 78
235 80
245 83
255 85
265 88
275 90
285 92
295 95
305 97
325 101
355 108
375 112
405 118
500 134
600 149
700 159
Superheat
Only check superheat after establishing the steady state
operation of the unit, pulling down the discharge air tem-
perature to within the control range, and running the unit
in a fully loaded condition.
The superheat is calculated as the difference between
the actual temperature of the refrigerant gas in the suc-
tion line and the temperature corresponding to the suc-
tion pressure as shown in Table 25.
For example, when the suction pressure is 130 psig and
the suction line temperature is 57.0°F:
• Saturation Temperature for 130 psig = 45.0°F
• Evaporator Superheat = Suction Line Temperature
(57.0°F) minus Saturation Temperature (45.0°F)
= 12.0°F
When adjusting the expansion valve, do not turn the
adjusting screw more than one turn at a time This al-
lows sufficient time (approximately 15 minutes) be-
tween adjustments for the system and the thermal ex-
pansion valve to respond and stabilize.
The superheat setting should be adjusted to 8.0–11.0°F
at design conditions.
Leak Checking
Leak check compressors, fittings, and piping to ensure
there are no leaks. Verify the evaporator distributor
tubes do not have bare copper touching each other or
are against a sheet metal edge. If leak checking a unit
charged with R-410A, ensure the leak test device is ca-
pable of sensing refrigerant R-410A.

Startup (Cooling)

Prestart Checklist
After installation has been completed, make the fol-
lowing checks:
1. Check the electrical supply voltage. Ensure that it
is the same as listed on the unit nameplate.
2. Set the room thermostat to the OFF position.
3. Turn ON the unit electrical power.
4. Set the room thermostat fan switch to ON.
5. Check the indoor blower rotation.
6. Check the blower drive belt tension.
7. Check the unit's supply air (CFM).
FORM 145.32-IOM5
ISSUE DATE: 04/08/2019