Important Refrigeration Components; Thermal Expansion Valve; Table 19 Packaged Units Without Receivers; Table 20 Packaged Units With Receivers - Data Aire DAPA-2.5 Installation, Operation & Maintenance Manual

nameplate. Although this figure represents the initial factory charge, it is still necessary to measure and
note proper unit operation including superheat, head and suction pressure. Some adjustment of charge
may be required.
Adjust the refrigerant charge until the sight glass has sparse bubbles. The system should be allowed
to stabilize for 15 to 20 minutes before meaningful measurements can be taken. After the system
stabilize, verification of a few key measurements should be noted.
Acceptable parameters range for water/glycol packaged units without receiver, with return air temperature of

65°F (18.3 C) to 85°F (29.4
Liquid Line
Refrigerant
Pressure PSIG (kPa)
290 to 390
R-410A
(1999 to 2689)
245 to 285
R-407C
(1689 to 1965)
Acceptable parameters range for water/glycol packaged units with receivers, with return air temperature of 65°F

(18.3 C) to 85°F (29.4
Liquid Line
Refrigerant
Pressure PSIG (kPa)
290 to 390
R-410A
(1999 to 2689)
245 to 285
R-407C
(1689 to 1965)
Measure the superheat at the compressor suction line at least 6 inches (152 mm) away from the
compressor.
All water/glycol cooled units have a water regulating valve. A head pressure transducer is connected
to a Schrader fitting on the discharge line and water is regulated into the condenser coil (plate fin
condensers are standard).

Important Refrigeration Components

Thermal Expansion Valve

Table 19 Packaged Units

C) and entering water/glycol temp of 65°F (18.3
Liquid Line
Suction Pressure
PSIG (kPa)
Temp °F (°C)
103 to 130
85 to 100
(710 to 896)
(29.4 to 37.8)
106 to 115
(365 - 483)
(41.1 to 46.1°)
Table 20 Packaged Units

C) and entering water/glycol temp of 65°F (18.3
Liquid Line
Suction Pressure
PSIG (kPa)
Temp °F (°C)
85 to 100
(710 to 896)
(29.4 to 37.8)
106 to 115
(365 - 483)
(41.1 to 46.1°)
WARNING: If the system is charged from a vacuum, the preheating of the
compressor is not necessary. But if starting a compressor that has not
been charged from a vacuum, the crankcase heater must be energized
for a minimum of 12 hours to reduce the possibility of liquid slugging on
startup. Failure to energize the crankcase heater could result in
compressor damage.
without Receivers
Suction Sat.
Temp °F (°C)
33 to 45
(0.56 to 7.2)
or greater
53 to 70
33 to 45
(0.56 to 7.2)
or greater
with Receivers
Suction Sat.
Temp °F (°C)
103 to 130
33 to 45
(0.56 to 7.2)
or greater
53 to 70
33 to 45
(0.56 to 7.2)
or greater
59
 
C) to 85°F (29.4 C)
Superheat
Subcooling
Temp °F (°C)
Temp °F (°C)
8 to 15 12 to 18
(-13.3 to -9.4) (-11.1 to -7.8)
8 to 10° 8 to 15°
(-13.3 to 12.2°) (-13.3 to -9.4°)
 
C) to 85°F (29.4 C)
Superheat
Subcooling
Temp °F (°C)
Temp °F (°C)
0 to 3° 12 to 18
(-17.8 to -16.1) (-11.1 to -7.8)
8 to 15°
0 to 3°
(-13.3 to -9.4°)
(-17.8 to -16.1)