Page 9
XC15 SERIES
Flushing Existing Line Set & Indoor Coil
WARNING
Danger of fire. Bleeding the refriger-
ant charge from only the high side
may result in the low side shell and
suction tubing being pressurized. Ap-
plication of a brazing torch while
pressurized may result in ignition of
the refrigerant and oil mixture − check
the high and low pressures before un-
brazing.
CAUTION
This procedure should not be performed on sys-
tems which contain contaminants (Example: com-
pressor burn out).
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 R−410A refrigerant. Residual mineral oil can
act as an insulator, preventing proper heat trans-
fer. It can also clog the expansion device, and re-
duce the system performance and capacity.
Failure to properly flush the system per the in-
structions below will void the warranty.
Required Equipment
Equipment required to flush the existing line set and indoor
coil:
S
two clean R−22 recovery bottles,
S
oil−less recovery machine with pump-down feature,
S
2 gauge sets (one for R−22; one for R−410A).
Flushing Procedure
IMPORTANT
The Environmental Protection Agency (EPA) pro-
hibits the intentional venting of HFC refrigerants
during maintenance, service, repair and disposal of
appliance. Approved methods of recovery, recycl-
ing or reclaiming must be followed.
1. Remove existing R−22 refrigerant using the following,
appropriate procedure (see figure 13):
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 R−22 refrigerant
to flush the system −
D
Disconnect all power to the existing outdoor unit.
D
Connect to the existing unit, a
clean
recovery cyl-
inder and the recovery machine according to the
instructions provided with the recovery machine.
D
Remove all R−22 refrigerant from the existing sys-
tem. Check gauges after shutdown to confirm that
the entire system is completely void of refrigerant.
D
Disconnect the liquid and vapor lines from the ex-
isting outdoor unit.
If the existing outdoor unit is equipped with
manual shut−off valves AND you plan to use NEW
R−22 refrigerant to flush the system
−
D
Start the existing R−22 system in the cooling mode
and close the liquid line valve.
D
Pump all of the existing R−22 refrigerant back into
the outdoor unit. (It may be necessary to bypass
the low pressure switches to ensure complete re-
frigerant evacuation.)
D
When the low side system pressures reach 0 psig,
close the vapor line valve.
D
Disconnect all power to the existing outdoor unit.
Check gauges after shutdown to confirm that the
valves are not allowing refrigerant to flow back into
the low side of the system.
D
Disconnect the liquid and vapor lines from the ex-
isting outdoor unit.
2. Remove the existing outdoor unit. Set the new R−410A
unit and follow the brazing connection procedure (see
page 7) to make line set connections.
