Refrigerant Charge - Carrier 50PG20-28 Controls, Start-Up, Operation, Service And Troubleshooting Instructions

5OOO
45OO
4OOO
35OO
3000
o 2500
2000
1500
1000
5OO
LEAK IN
VACUUM TIGHT
TOO WET
TIGHT
DRY SYSTEM
0 1 2 3 4 5 6 7
MINUTES
Fig. 41 -- Deep Vacuum Graph
TRIPLE EVACUATION METHOD The triple evacumion
method should only be used when vacuum pump is capable of
pumping down to 28 in. of mercury and system does not con-
tain any liquid ,a_ater. P roceed as follows:
1. Pump system down to 28 in. of mercury and allow pump
to continue operating for an additional 15 minutes.
2. Close service valves and shut off vacuum pump.
3. Connect a nitrogen cylinder and regulator to system and
open until system pressure is 2 psig.
4. Close service valve and allow system to stand for 1 hr.
During this time, dry nitrogen will be able to diffuse
throughout the system, absorbing moisture.
5. Repeat this procedure. System will then contain minimal
amounts of contmninants and water vapor.
Refrigerant Charge -- Amount of refrigerant charge is
listed on unit nameplate. Refer to Carrier GTAC II; Module 5;
ChaNing, Recovery, Recycling, and Reclmnation section for
charNng methods and procedures. Unit panels must be in place
when unit is operating during charging procedure.
Puron_r9(R-410A) refrigerant cylinders contain a dip tube
which allows liquid refiigerant to flow tiom the cylinder in an
upright position. ChaNe units with cylinder in the upright
position and a colrnnercial type metering device in the mani-
fold hose.
TO USE THE COOLING CHARGING CHART, STAN-
DARD UNITS Use the above temperature and pressure
readings, and find the intersection point on the cooling chaN-
ing chart. If intersection point on chart is above line, add refiig-
erant. If intersection point on chart is below line, carefully re-
cover some of the charge. Recheck suction pressure as charge
is adjusted.
CHARGING CHART (ALL CIRCUITS)
ALL OUTDOORFANS MUST BE OPERATING
150 ?00 _50 SO0 aS0 Io0 IS0 500 550
Liquid Pressure
el
Liqu{d V0{_e, [psig]
qq
H
H
H
H
'1!
Fig. 42 -- Charging Chart -- 48/50PG20 --
Standard Unit
CHARGING CHART
ALL OUTDOOR FANS MUST BE OPERATING
Liquid Pressure at Liquid Valve, [psig]
This system uses Puron refi'igerant which Ms higher
pressures than R-22 and other refiigerants. No other refrig-
erant may be used in this system. Gage set, hoses, and
recovery system must be desigqed to handle Puron refrig-
erant. If unsure about equipment, consult the equipment
manuthcturer.
NOTE: Do not use recycled refiigerant as it may contain
contaminants.
NO CHARGE Use standard evacuating techniques. After
evacuating system, weigh in the specified amount of refiiger-
ant (refer to unit nameplate).
NOTE: System chmge for units with Humidi-MiZer
TM
system
is greater than the system charge of the standard unit.
LOW CHARGE COOLING Using cooling chmging chart
(see Fig. 42-45), add or relnove refiigerant until conditions of the
chart are met. An accurate pressure gage and telnperature-
sensing device are required. Charging is accomplished by
ensuring the proper amount of liquid subcooling. Measure liquid
line pressure at the liquid line service valve using pressure gage.
Connect telnperature sensing device to the liquid line near the
liquid line service valve and insulate it so that outdoor ambient
temperature does not affect reading.
Fig. 43 -- Charging Chart -- 48/50PG20 --
Unit with Humidi-MiZeW MSystem
CHARGING CHART (ALL CIRCUITS)
ALL OUTDOOR FANS MUST BE OPERATING
_so 2oo 25o sou &5o _oo aso 500 sso 6oo
Liquid Pressure o_ Liquid
Volve,
[psig}
Fig. 44 -- Charging Chart -- 48/50PG24 -- Standard
Unit and Unit with Humidi-MiZeW MSystem
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