3. If the lines must pass under or through a concrete
slab ensure lines are adequately protected and
sealed.
REFRIGERANT LINE CONNECTIONS
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 ofthe 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
R410A 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 piston size by
checking the piston kit chart packaged with indoor
unit.
LEAK TESTING (NITROGEN OR NITROGEN-
TRACED)
WARNING
WARNING
TO AVOID THE RISK OF FIRE OR EXPLOSION NEVER
USE OXYGEN HIGH PRESSURE AIR OR FLAMMABLE
GASES FOR LEAK TESTING OF REFRIGERATION
SYSTEM.
WARNING
WARNING
TO AVOID POSSIBLE EXPLOSION THE LINE FROM
THE NITROGEN CYLINDER MUST INCLUDE A
PRESSURE REGULATOR AND A PRESSURE RELIEF
VALVE. THE PRESSURE RELIEF VALVE MUST BE SET
TO OPEN AT NO MORE THAN 150 PSIG.
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.
SYSTEM EVACUATION
WARNING
WARNING
REFRIGERANT UNDER PRESSURE!
FAILURE TO FOLLOW PROPER PROCEDURES MAY
CAUSE PROPERTY DAMAGE PERSONAL INJURY OR
DEATH
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.
NOTE: Scroll compressors should never be used to
evacuate or pump down a heat pump or air
conditioning system.
NOTE: Prolonged operation at suction pressures less
than 20 psig for more than 5 seconds will result in
overheating of the scrolls and permanent damage to
the scroll tips drive bearings and internal seal.
NOTE: Holding charge must be removed before
brazing.
1. Open service valves before attaching vacuum
pump.
Copyright © 2019 DewAir Corporation 7 RHC18O-IM v2.11 Sep , 2019
