Table 15: R-410A pressure and temperature chart
PSIG
Temp ˚F
PSIG
Temp ˚F
54
4
265
88
56
6
275
90
58
7
285
92
60
8
295
95
62
10
305
97
64
11
325
101
66
13
355
108
68
14
375
112
70
15
405
118
72
16
500
134
74
17
600
149
76
19
700
159
Superheat
Only check superheat after establishing the steady state operation of the unit, pulling down the
discharge air temperature 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 suction line and the temperature corresponding to the suction pressure as shown in Table
15.
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 allows sufficient time (approximately 15 minutes) between adjustments for the system and the
thermal expansion 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 capable of sensing
refrigerant R-410A.
Microprocessor controller
The microprocessor control system is specifically designed for single and dual stage systems. The
control system interfaces with a conventional type thermostat.
•
Unit shall be complete with self-contained low-voltage control circuit.
•
Unit shall incorporate a lockout circuit which provides reset capability at the space
thermostat or base unit, should any of the following standard safety devices trip and shut off
compressor.
- Loss-of-charge/low-pressure switch
- High-pressure switch
- Condensate overflow protection switch
C-Series Vertical (CSV) Water-Cooled Self-Contained Units, B Generation, R-410A Installation, Operation, and
Maintenance Manual
64
