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18-GL07D1-4
2GN SPLIT INSTALLER’S GUIDE
Leak Testing
The refrigeration line set must be pressurized and checked
for leaks before purging and charging the unit. To pressurize
the line set, attach refrigerant gauges to the service ports and
add an inert gas (nitrogen or dry carbon dioxide) until pressure
reaches 60 to 90 PSIG. Never use oxygen or acetylene to
pressure test. Use an electronic leak detector or a good quality
bubble solution to detect leaks on all connections made in the
fi eld. Check the service valve ports and stem for leaks and all
connections made in the fi eld. If a leak is found, repair it and
repeat the above steps. For safety reasons do not pressurize
the system above 150 psi. Purge pressure from line set. The
system is now ready for evacuating and charging.
System Evacuation
Ensure that the line set and air coil are evacuated before
opening service valves to the split unit. The line set must be
evacuated to at least 200 microns to remove the moisture
and air that may still be in the line set and coil. Evacuate the
system through both service ports to prevent false readings
on the gauge because of pressure drop through service ports.
Charge Amount When Using TAMG Air
Handler
The 2GN Split is shipped with a factory pre-charge. This
volume of refrigerant is not suffi cient to run the system and
additional refrigerant must be added. If using an TAMG Air
Handler please refer to the Line Set Sizes table for charge
amounts to be added. The “Factory Charge” column is the
charge amount the compressor section/split is shipped with
from the factory. The “Charge Amount with TAMG Air Handler”
column is the total amount of charge for the TAMG Air Handler
+ Compressor section/split. This column does not factor in
additional refrigerant needed for the line set. The installer of the
system must add charge appropriately for the specifi c length
of the line set. A 3/8 in. liquid line is calculated at 0.50 oz. of
charge per linear foot, and a 1/2 in. liquid line is calculated at
1.0 oz. of charge per linear foot using R-410A refrigerant. The
suction line will not hold “liquid” and should be ignored for the
charge calculation.
Example:2GN038/TAMGA0C36 with 20 ft. of 3/8 in. liquid
line. Remember that when using the TAMG Air Handler,
the column “Charge Amount with TAMG Air Handler” will
be used. Now calculate for the additional 20 ft. line set.
Additional refrigerant to be added = (20 ft. x 0.5 oz.) = 10
oz.
Solution: 10 oz. should be added to the recommended
charge of 82 oz. found in the “Charge Amount with TAMG
Air Handler” column for a total charge of 92 oz.
After initial charge, the system should be operated and
the system subcooling and superheat verifi ed to the
Operating Parameters table.
If an air handler manufactured by others is used then
refrigerant should be added to the 2GN Split factory charge
pre-charge. Refrigerant should be added for liquid line length.
This should result in a slightly under-charged system exhibiting
low subcooling and high superheat. As charge is added, the
subcooling should rise and the superheat should fall.
Charging the System
Charge Method – After purging and evacuating the line set,
fully open the service valves counterclockwise. Add R-410A
(liquid) into the liquid line service port until the pressure in
the system reaches approximately 200 PSIG. Never add
liquid refrigerant into the suction side of a compressor. Start
the unit and measure superheat and subcooling. Keep adding
refrigerant until the unit meets the superheat and subcooling
values on the Operating Parameters tables.
Checking Superheat and Subcooling
Determining Superheat
1. Measure the temperature of the suction line at the
point where the expansion valve bulb is clamped.
2. Determine the suction pressure in the suction line
by attaching refrigeration gauges to the schrader
connection on the suction side of the compressor.
3. Convert the pressure obtained in Step 2 to the
saturation temperature by using the R-410A Pressure/
Temperature Conversion Chart.
4. Subtract the temperature obtained in Step 3 from
Step 1. The difference is the amount of superheat for
the unit. Refer to the Operating Parameters tables for
superheat ranges at specifi c entering water conditions.
Superheat Adjustment
TXVs are factory set to a specifi c superheat; however, the
superheat should be adjusted for the application. To adjust the
TXV to other superheat settings:
Remove the seal cap from the bottom of the valve.
Turn the adjustment screw clockwise to increase superheat
and counterclockwise to decrease superheat. One complete
360° turn changes the superheat approximately 3-4°F,
regardless of refrigerant type. You may need to allow as much
as 30 minutes after the adjustment is made for the system to
stabilize.
Once the proper superheat setting has been achieved, replace
and tighten the seal cap.
WARNING
!
There are 8 total (360°) turns on the superheat
adjustment stem from wide open to fully closed.
When adjusting the superheat stem clockwise
(superheat increase) and the stop is reached, any
further clockwise turning adjustment will damage
the valve.
Summary of Contents for 2GN Series
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