STULZ CyberRow DX Series Installation, Operation & Maintenance Manual
Table3
Weight of R410A Refrigerant
(Lbs./100 Ft of type L tubing)
Line
Size
O.D.
Liquid Line
Discharge
Line
1/2
5.88
1.27
5/8
9.44
2.03
7/8
19.62
4.22
1 1/8
33.44
7.20
1 3/8
50.95
10.97
1 5/8
72.11
15.53
2 1/8
158.29
34.09
Example:
Estimate the amount of refrigerant required
for a refrigeration circuit in a system using R410A
refrigerant consisting of a CRS-042-A unit connected
with a 1/2” x 30 foot liquid line and 7/8” x 30 foot
discharge line to a STULZ Model SCS-060 condenser.
A/C Unit
=
3.9 lbs
+ 1/2” Liquid Line- 30 x 5.88
=
1.764 lbs
100
+ 7/8” Discharge Line- 30 x 4.22 =
1.266 lbs
100
+ Condenser
=
2.8 lbs
Estimated Refrigerant Charge =
9.73 lbs
(Round off to nearest 0.1 lb = 9.7 lbs)
2.10.2.2 Preparing System For Charging
1.
With all the system piping connections made,
perform a dry nitrogen leak detection test on
the system. Using dry nitrogen only, pressurize
the system to 150 psig. Ensure all service
and solenoid valves are energized open and
that no part of the system is isolated from the
pressurized nitrogen.
2.
Since there is no refrigerant in the system to
detect at this point, leaks may be detected
by observing if there’s been a change in the
standing pressure after 12 hours. A signifi cant
drop in pressure (>10 psig) indicates a leak in
the system that needs to be repaired. After the
system is determined to be free of leaks, you
may evacuate the system.
EVACUATE THE SYSTEM
CAUTION
A proper vacuum must be drawn on the
refrigerant system to remove moisture prior
to charging. If this is not done the refrigerant
charge will combine with moisture in the
pipes to form an acid that will eventually lead
to compressor failure. A triple evacuation
procedure with dry nitrogen is recommended
especially for systems with newly installed
refrigerant piping.
NOTE
A vacuum pump should be used that is capable
of evacuating the entire volume of the A/C
system, including newly installed or existing
piping. It is essential to use a well maintained
pump that is in good operating condition.
Always ensure it contains clean, fresh oil.
Manufacturers recommend you change the oil
in the pump regularly to maintain its ability to
remove moisture.
NOTE
Use high quality hoses ensuring they are free of
defects and don’t leak. It is recommended to use
copper tubing instead of hoses if possible due
to the low vacuum that must be attained when
evacuating the system. The use of short, large
diameter hoses helps reduce evacuation time.
3. After ensuring there are no leaks, relieve pressure
and evacuate the entire system while maintaining
all the solenoids open. Pull an initial vacuum
of 1500 microns or lower using the suction and
discharge service ports.
NOTE
When pulling a vacuum, the schrader valves will
unnecessarily restrict the openings, increasing the
evacuation time. During the evacuation process
it is recommended to remove the schrader valve
cores with a schrader valve removal tool and draw
the vacuum through the port on the removal tool.
4. If you cannot evacuate the system below 1500
microns, close the vacuum pump isolation valve
and perform a rate-of-rise test by observing the
standing pressure over time. If the pressure rises
slowly (up to 200 microns in 15 minutes) it indicates
2-15
Содержание CyberRow DX CRS-042-G
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