4
B
URYING
R
EFRIGERANT
L
INES
If burying refrigerant lines can not be avoided, use the following
checklist.
1. Insulate liquid and suction lines separately.
2. Enclose all underground portions of the refrigerant lines
in waterproof material (conduit or pipe) sealing the ends
where tubing enters/exits the enclosure.
3. If the lines must pass under or through a concrete slab,
ensure lines are adequately protected and sealed.
R
EFRIGERANT
L
INE
C
ONNECTIONS
IMPORTANT
To avoid overheating the service valve, TXV valve, or filter
drier while brazing, wrap the component with a wet rag, or
use a thermal heat trap compound. Be sure to follow the
manufacturer’s instruction when using the heat trap
compound. Note: Remove Schrader valves from service valves
before brazing tubes to the valves. Use a brazing alloy of 2%
minimum silver content. Do not use flux.
Torch heat required to braze tubes of various sizes is
proportional to the size of the tube. Tubes of smaller size
require less heat to bring the tube to brazing temperature
before adding brazing alloy. Applying too much heat to any
tube can melt the tube. Service personnel must use the
appropriate heat level for the size of the tube being brazed.
NOTE: The use of a heat shield when brazing is recommended
to avoid burning the serial plate or the finish on the unit.
1. The ends of the refrigerant lines must be cut square,
deburred, cleaned, and be round and free from nicks or
dents. Any other condition increases the chance of a
refrigerant leak.
2. “Sweep” the refrigerant line with nitrogen or inert gas
during brazing to prevent the formation of copper-oxide
inside the refrigerant lines. The POE oils used in R-410A
applications will clean any copper-oxide present from the
inside of the refrigerant lines and spread it throughout the
system. This may cause a blockage or failure of the metering
device.
3. After brazing, quench the joints with water or a wet cloth to
prevent overheating of the service valve.
4. Ensure the filter drier paint finish is intact after brazing. If
the paint of the steel filter drier has been burned or
chipped, repaint or treat with a rust preventative. This is
especially important on suction line filter driers which
are continually wet when the unit is operating.
NOTE:
Be careful not to kink or dent refrigerant lines. Kinked or
dented lines will cause poor performance or compressor damage.
Do NOT make final refrigerant line connection until plugs are
removed from refrigerant tubing.
NOTE:
Before brazing, verify indoor TXV is correct for R410A and
proper size.
L
EAK
T
ESTING
(N
ITROGEN
OR
N
ITROGEN
-T
RACED
)
T
O
AVOID
THE
RISK
OF
FIRE
OR
EXPLOSION
,
NEVER
USE
OXYGEN
,
HIGH
PRESSURE
AIR
OR
FLAMMABLE
GASES
FOR
LEAK
TESTING
OF
A
REFRIGERATION
SYSTEM
.
WARNING
T
O
AVOID
POSSIBLE
EXPLOSION
,
THE
LINE
FROM
THE
NITROGEN
CYLINDER
MUST
INCLUDE
A
PRESSURE
REGULATOR
AND
A
PRESSURE
RELIEF
VALVE
. T
HE
PRESSURE
RELIEF
VALVE
MUST
BE
SET
TO
OPEN
AT
NO
MORE
THAN
150
PSIG
.
WARNING
Pressure test the system using dry nitrogen and soapy water to
locate leaks. If you wish to use a leak detector, charge the system
to 10 psi using the appropriate refrigerant then use nitrogen to
finish charging the system to working pressure then apply the
detector to suspect areas. If leaks are found, repair them. After
repair, repeat the pressure test. If no leaks exist, proceed to sys-
tem evacuation.
S
YSTEM
E
VACUATION
Condensing unit liquid and suction valves are closed to contain
the charge within the unit. The unit is shipped with the valve
stems closed and caps installed.
Do not open valves until the
system is evacuated.
REFRIGERANT UNDER PRESSURE!
F
AILURE
TO
FOLLOW
PROPER
PROCEDURES
MAY
CAUSE
PROPERTY
DAMAGE
,
PERSONAL
INJURY
OR
DEATH
.
WARNING
NOTE:
Scroll compressors should never be used to evacuate or
pump down a heat pump or air conditioning system.
