Johnson Controls
Start-Up & Operation Guide | 5586996-JSG-A-0120
17
Start-Up
EXAMPLE: The suction pressure is 130 PSIG and the
suction line temperature is 57.0 F.
Suction line temperature = 57.0°F
Saturation temperature for 130 PSIG = 45.0°F
Evaporator superheat = 12.0°F
CAUTION
When adjusting the expansion valve, DO NOT turn
the adjusting screw more than one turn at a time.
Allow for sufficient time (approximately 15 minutes)
between adjustments for the system and the TXV
to respond and stabilize.
The superheat setting should be adjusted to 12.0°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 and that
they are not against a sheet metal edge. If leak checking
a unit charged with R-410A, ensure the leak test device
is capable of sensing refrigerant R-410A.
If the unit is functioning satisfactorily during the initial
operating period, no safeties trip, and the unit controls
are properly functioning, the rooftop unit is ready to be
placed into operation.
Gas Heat Models
WARNING
ELECTRICAL SHOCK, FIRE, OR EXPLOSION
HAZARD
Failure to follow safety warnings exactly, as well as
improper servicing, can result in dangerous opera-
tion, serious injury, death, or property damage.
• Before servicing, disconnect all electrical
power to furnace.
• When servicing controls, label all wires prior
to disconnecting. Reconnect wires correctly.
• Verify proper operation after servicing.
Table 8: R-410A Pressure/Temperature Chart
PSIG TEMP (˚F) PSIG TEMP (˚F) PSIG TEMP (˚F) PSIG TEMP (˚F)
0 -60 40 -6 80 21 210 73
2 -58 42 -4 85 24 220 76
4 -54 44 -3 90 26 225 78
6 -50 46 -2 95 29 235 80
8 -46 48 0 100 32 245 83
10 -42 50 1 105 34 255 85
12 -39 52 3 110 36 265 88
14 -36 54 4 115 39 275 90
16 -33 56 6 120 41 285 92
18 -30 58 7 125 43 295 95
20 -28 60 8 130 45 305 97
22 -26 62 10 135 47 325 101
24 -24 64 11 140 49 355 108
26 -20 66 13 145 51 375 112
28 -18 68 14 150 53 405 118
30 -16 70 15 160 57 500 134
32 -14 72 16 170 60 600 149
34 -12 74 17 180 64 700 159
36 -10 76 19 190 67
38 -8 78 20 200 70
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