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AC2-Series Outdoor Unit Line Set
Line Set Interconnect Tubing
The indoor unit connections for the interconnect line set
are brass service valves with flared fittings. Both lines of the
interconnecting tubing are 1/2" OD; outgoing line is hot
discharge gas from compressor, and the return line to PC unit is
liquid refrigerant.
Copper flare to solder adapters are included with the
indoor unit, to remove the requirement to do an accurate
flare in the field. These are shipped along with the
mounting feet for the outdoor unit near the compressor in the
indoor unit.
IMPORTANT NOTE: The line set between the
indoor and outdoor units must not exceed 70
ft (21 m) in length.
The outdoor unit has capped off (soldered) pipes from the
factory and is charged with 15 - 25 psig of nitrogen. The indoor
unit comes pre-charged with enough refrigerant for a 20 ft
(6.1 m) line set. Once both the indoor and outdoor units
have been mounted, the line set may be run between them.
The wrench size for access valve caps as well as the hex key
size to open/close the valves is indicated in the table.
TABLE 18 - Interconnect Line Set Tools
Hex Key
Cap Wrench
5mm (3/16")
19mm (3/4")
Remove the side cover from the outdoor unit so that the
piping is accessible. See earlier diagram
illustration of a typical installation.
The tubing used must be ACR refrigeration tubing (cleaned
& dehydrated). Every effort must be made to insure that the
tubing does not become contaminated during installation. It is
recommended that caps be placed on the open ends of tubing
immediately after cuts are made and that these caps are only
removed after all bends have been made and the pipe fixed in
its permanent location ready to make the silver soldered joints.
It is very important to keep a refrigeration system perfectly clean
and dry. Removing the caps just prior to silver soldering will
ensure minimum exposure to humidity in the atmosphere.
Oil Traps
If the line set has a vertical rise of over 20 ft (6 m), then
an oil trap must be placed in the line set every 20 ft (6 m) of rise.
ISSUE 03: 1-Oct-2021
Service Port Cap Wrench
14mm (9/16")
002297PDG
for
Page 22
Pipe Insulation
All line set piping between the indoor and outdoor units
should be insulated with 3/8" thick closed cell pipe insulation to
prevent heat transfer to or from the lines. It can be slid onto the
capped tubing without having to slice it down the side for the
most part. Ensure that any joints in in the line sets are
accessible for leak testing.
Ports and any remaining exposed tubing should be
insulated with 3/8" thick closed cell pipe insulation once the
silver soldering and pressure testing is complete. Ensure that
all individual pieces of pipe insulation are glued to each other so
there are no air gaps.
Silver Soldering Line Sets
All joints are to be silver soldered with 5% silver solder. It
is absolutely required that dry nitrogen be bled through the
system during all silver soldering procedures so that no
oxidation occurs on the inside of the copper tubing.
Connect a set of refrigeration gauges to the service ports
(Schrader ports) on the access valves of the indoor unit, the low
side (blue hose) to the vapour line and the high side (red hose)
to the liquid line. Connect the charge line (yellow hose) to a
nitrogen source. Disconnect the high side (red) hose at the
manifold so that nitrogen may flow freely though the line set.
Adjust the nitrogen pressure through the low side (blue hose) so
that it can be very lightly felt when a finger is placed on the
disconnected high side (red) hose.
A wet rag may be wrapped around each of the outdoor unit
ports to prevent melting the grommet when silver soldering;
however this should not be necessary due to the distance from
the grommet. Ensure that no water enters any of the ports or
tubing.
Pressure Testing
Once all connections are complete, the system should be
pressure tested to a final test pressure of 125 psig (860 kPa)
with dry nitrogen. Reconnect the high side (red) hose to the
manifold and pressurize the line set. It is recommended to
pressure test in stages, listening and inspecting for leaks along
the way. For example, 10 psig (70 kPa) , 25 psig (170kPa), 75
psig (520kPa) and then finally 125PSIG (860kPa). Check all
joints at the unit and any made in the interconnect tubing for
leaks using soap suds, Spray Nine, etc. It is important not to
bypass this step as vacuuming the system with a leak will be
impossible and attempting to do so will introduce moisture into
the system, making the vacuum process take much longer than
if the leak had been found and repaired first. It is recommended
that the system be left under pressure for a minimum of two
hours to ensure there are no small leaks that were undetected.
Vacuuming the System
Remove the pressure from the system and connect the
vacuum pump to the charge line (yellow hose) of the
refrigeration manifold. Tighten all hose connections, open the
valves on the manifold and start the vacuum pump.
Vacuum the system until the reading on an electronic
vacuum gauge remains below 500 microns for a period of 5
minutes after the vacuum pump is shut off and the system
sealed.
002291MAN-03
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