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 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.
L
EAK
T
ESTING
(N
ITROGEN
OR
N
ITROGEN
-
T
RACED
)
WARNING
WARNING
T
O
AVOID
THE
RISK
OF
FIRE
OR
EXPLOSION
,
NEVER
USE
OXYGEN
,
HIGH
PRESSURE
AIR
OR
FLAMMABLE
GASES
FOR
LEAK
TESTING
OF
REFRIGERATION
SYSTEM
.
WARNING
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
.
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.
S
YSTEM
E
VACUATION
WARNING
WARNING
REFRIGERANT UNDER PRESSURE!
F
AILURE
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 4, 2019
