# 48387H005
Page 7
Brazing Connection Procedure
1. Cut ends of refrigerant lines square (free from nicks
or dents). Debur the ends. The pipe must remain
round; do not pinch end of line.
2. Before making line set connections, use dry nitrogen to
purge the refrigerant piping. This will help to prevent
oxidation and the introduction of moisture into the system.
3. Use silver alloy brazing rods (5% or 6% silver alloy for
copper-to-copper brazing or 45% silver alloy for
copper-to-brass or copper-to-steel brazing) which are
rated for use with R410A refrigerant.
4.
Remove the Schrader core assemblies before brazing
to protect them from damage due to extreme heat.
Replace the cores when brazing is complete.
5. Remove light maroon washers from service valves and
shield light maroon stickers to protect them during
brazing. Wrap a wet cloth around the valve body and
copper tube stub to protect it from heat damage.
6. Braze the line set to the service valve. Quench the joints
with water or a wet cloth to prevent heat damage to the
valve core and opening port.
The tube end must stay
bottomed in the fitting during final assembly to
ensure proper seating, sealing, and rigidity.
7. Install the factory-supplied fixed orifice (or thermal
expansion valve which is sold separately and which is
approved for use with R410A refrigerant) in the liquid
line at the indoor coil (see
Refrigerant Metering
Device
on page 9).
Flushing Existing Line Set and Indoor Coil
Polyol ester (POE) oils used with R410A
refrigerant absorb moisture very quickly. It is
very important that the refrigerant system be
kept closed as much as possible. DO NOT
remove line set caps or service valve stub
caps until ready to make connections.
WARNING
When flushing existing line set and/or indoor
coil, be sure to empty all existing traps. Residual
mineral oil can act as an insulator, preventing
proper heat transfer. It can also clog the thermal
expansion valve, reducing system performance
and capacity. Failure to properly flush system as
explained in these instructions will void warranty.
CAUTION
This procedure should not be performed on systems
which contain contaminants, such as compressor
burn out.
Required Equipment
The following equipment is needed to flush the existing
line set and indoor coil (see Figure 10 on page 8): Two
clean R22 recovery bottles, an oil-less recovery machine
with a “pump down” feature, and two sets of gauges (one
for use with R22 and one for use with R410A).
Flushing Procedure
IMPORTANT:
The line set and/or indoor coil must be
flushed with at least the same amount of refrigerant that
previously charged the system. Check the charge in the
flushing cylinder before flushing the unit.
1. Remove existing R22 refrigerant using the appropriate
procedure.
If the existing outdoor unit is not equipped with shutoff
valves, or if the unit is not operational AND the
existing
R22 refrigerant will be used to flush the system:
Disconnect all power to the existing outdoor unit.
Connect the existing unit, a clean recovery cylinder, and
the recovery machine according to the instructions
provided with the recovery machine. Remove all R22
refrigerant from the existing system. Refer to the
gauges after shutdown to confirm that the entire system
is completely void of refrigerant. Disconnect the liquid
and suction lines from the existing outdoor unit.
If the existing outdoor unit is equipped with manual
shutoff valves AND
new
R22 refrigerant will be used
to flush the system:
Start the existing R22 refrigerant system in cooling mode
and close the liquid line valve. Pump all the existing R22
refrigerant back into the outdoor unit.
(It may be necessary to bypass the low pressure
switches to ensure complete refrigerant evacuation.)
