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Refrigerant Connections
HSXA15 Matched with New Indoor Coil and Line Set
If an existing indoor coil that was equipped with an
RFCI metering device is being replaced, the liquid line
must also be replaced prior to the installation of the
HSXA15 unit.
If refrigerant lines are routed through a wall, seal and isolate
the opening so vibration is not transmitted to the building.
WARNING
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 ser-
vice valve stub caps until you are ready to make
connections.
Brazing Connection Procedure
1 − Cut ends of the refrigerant lines square (free from nicks
or dents). Debur the ends. The pipe must remain
round, do not pinch end of the 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 sys-
tem.
3 − Use silver alloy brazing rods (5 or 6 percent silver alloy
for copper−to−copper brazing or 45 percent silver alloy
for copper−to−brass or copper−to−steel brazing) which
are rated for use with R410A refrigerant. Wrap a wet
cloth around the valve body and the copper tube stub.
Remove light maroon washers from service valves and
shield light maroon stickers in order to protect them
during brazing. Braze the line set to the service valve.
4 − Wrap a wet cloth around the valve body and copper
tube stub to protect it from heat damage during braz-
ing. Wrap another wet cloth underneath the valve body
to protect the base paint.
NOTE − The tube end must stay bottomed in the fitting
during final assembly to ensure proper seating, sealing
and rigidity.
5 − Install the provided thermal expansion valve (ap-
proved for use with R410A refrigerant) in the liquid line
at the indoor coil.
6 − Install the provided filter drier (approved for use with
R410A refrigerant) in the liquid line as close as pos-
sible to the expansion device.
Do not leave the filter
drier uncapped for more than 10 to 15 minutes
prior to brazing, evacuation and leak testing.
Polyol ester oils used in this system absorb mois-
ture quickly. Failure to install the filter drier will
void the warranty.
Flushing Existing Line Set & Indoor Coil
IMPORTANT
If this unit is being matched with an approved line
set or indoor coil which was previously charged
with mineral oil, or if it is being matched with a coil
which was manufactured before January of 1999,
the coil and line set must be flushed prior to instal-
lation. Take care to empty all existing traps. Polyol
ester (POE) oils are used in Lennox units charged
with R410A refrigerant. Residual mineral oil can act
as an insulator, preventing proper heat transfer. It
can also clog the thermal expansion valve, reduc-
ing system performance and capacity.
Failure to properly flush the system per the instruc-
tions below will void the warranty.
CAUTION
This procedure should not be performed on sys-
tems which contain contaminants (Example: com-
pressor burn out).
Required Equipment
You will need the following equipment in order to flush the
existing line set and indoor coil: two clean HCFC−22 recov-
ery bottles, an oilless recovery machine with a pump down
feature, and two sets of gauges (one for use with HCFC−22
and one for use with the R410A).
Flushing Procedure
1 − Remove existing HCFC−22 refrigerant using the ap-
propriate procedure below.
If the existing outdoor unit is not equipped with
shut−off valves, or if the unit is not operational
AND you plan to use the existing HCFC−22 refrig-
erant to flush the system –
Disconnect all power to
the existing outdoor unit. Connect to the existing unit,
a
clean
recovery cylinder and the recovery machine
according to the instructions provided with the recov-
ery machine. Remove all HCFC−22 refrigerant from
the existing system. Refer to gauges after shutdown to
confirm that the entire system is completely void of re-
frigerant. Disconnect the liquid and vapor lines from
the existing outdoor unit.
If the existing outdoor unit is equipped with manu-
al shut−off valves AND you plan to use NEW
HCFC−22 refrigerant to flush the system –
Start the
existing HCFC−22 system in the cooling mode and
close the liquid line valve. Pump all of the existing
HCFC−22 refrigerant back into the outdoor unit. (It may
be necessary to bypass the low pressure switches to
ensure complete refrigerant evacuation.) When the
low side system pressures reach 0 psig, close the va-
