Lennox XP14 Elite Series Installation Instructions Manual page 11

CAUTION
EQUIPMENT REQUIRED FOR FLUSHING LINE SET
The following equipment is required to flush the existing
line set and indoor coil:
• two clean HCFC-22 recovery cylinders
• oilless recovery machine with a pump down feature
• gauge set for HCFC-22 refrigerant
• gauge set for HFC-410A refrigerant (see Manifold
Gauge Set section on page 13),
FLUSHING PROCEDURE
1, Remove existing HCFC-22 refrigerant using the
following, applicable procedure as illustrated in figure
18:
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
refrigerant 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 recovery
machine,
• Remove all HCFC-22 refrigerant from the existing
system. Check 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
manual 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 vapor line valve.
• 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.
• Disconnect the liquid and vapor lines from the
existing outdoor unit,
Remove the existing outdoor unit, Set the new
HFC-410A unit and follow the Brazing Connection
Procedure provided on page 10 to make line set
connections. DO NOT install HFC-410A
check/expansion valve at this time.
Make low voltage and line voltage connections to the
new outdoor unit. DO NOT turn on power to the unit
or open the outdoor unit service valves at this
time.
Remove the existing HCFC-22 refrigerant flow control
orifice or check expansion valve before continuing with
flushing procedures. HCFC-22 flow control devices
(fixed orifice/check expansion valve) are not approved
for use with HFC-410A refrigerant and may prevent
proper flushing. Use a field-provided fitting to
reconnect the lines,
IMPORTANT
Inverted HCFC-22 Cylinder
(Contains clean HCFC-22 to be
used for flushing)
RECOVERY CYLINDER
EXISTING VAPOR LINE
VAPOR LINE
SERVICE VALVE
EXISTING LIQUID LINE
LIQUID LINE
SERVICE VALVE
Tank Return Inlet
, Discharge
RECOVERY MACHINE
Low High
Pressure Pressure
Opened ! ! Closed
NOTE - The inverted HCFC-22 cylinder must
contain at least the same amount of refrigerant
as was recovered from the existing system.
Figure 18. Flushing Connections
Page 11
XP14 SERIES