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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 minimum
silver alloy for copper−to−copper brazing or 45 percent
silver alloy for copper−to−brass or copper−to−steel braz-
ing) 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 pro-
tect them during brazing. Braze the line set to the ser-
vice 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 a field−provided thermal expansion valve (ap-
proved for use with R410A refrigerant) in the liquid line
at the indoor coil.
Flushing Existing Line Set & Indoor Coil
WARNING
Danger of fire. Bleeding the refrigerant
charge from only the high side may
result in the low side shell and suc-
tion tubing being pressurized. App-
plication of a brazing torch while pres-
surized may result in ignition of the
refrigerant and oil mixture − check the
high and low pressures before unbra-
zing.
If this unit is being matched with an approved line
set or indoor coil which was previously charged
with R22 refrigerant, 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
installation. 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, reducing system performance and capacity.
Failure to properly flush the system per the instruc-
tions below will void the warranty.
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 R22 recovery
bottles, an oilless recovery machine with a pump down fea-
ture, and two sets of gauges (one for use with R22 and one
for use with the R410A).
Flushing Procedure
1 − Remove existing R22 refrigerant using the appropri-
ate 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 R22 refrigerant to
flush the system −− Disconnect all power to the exist-
ing outdoor unit. Connect the existing unit, a clean re-
covery cylinder and the recovery machine according
to the instructions provided with the recovery ma-
chine. Remove all R22 refrigerant from the existing
system. Refer to gauges after shutdown to confirm
that the entire system is completely void of refrigerant.
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 R22
refrigerant to flush the system −− Start the existing
R22 system in the cooling mode and close the liquid
line valve. Pump all of the existing R22 refrigerant
back into the outdoor unit. (It may be necessary to by-
pass the low pressure switches to ensure complete re-
frigerant evacuation.) When the low side system pres-
sures reach 0 psig, close the vapor line valve. Discon-
nect all power to the existing outdoor unit. Refer to
Page 9
IMPORTANT
CAUTION
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