DSZC16 Installation Manual
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
)
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 system evacuation.
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