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504953M 03/06
Refrigerant Metering Device
HSXA16 units are used in thermostatic expansion valve
(TXV) systems only. See the Lennox Engineering Hand-
book for approved TXV match-ups and application infor-
mation.
Check expansion valves equipped with Chatleff fittings are
available from Lennox. Refer to the Engineering Hand-
book for applicable expansion valves for use with specific
match-ups.
If you install a thermostatic expansion valve (TXV)
with an indoor coil that includes a fixed orifice, re-
move the orifice before installing the TXV.
See figure 9
for installation of the TXV.
EXPANSION VALVE &
O−RING (See NOTE)
Metering Device Installation
STRAINER
LIQUID LINE
STUB
DISTRIBUTOR
Figure 9
O−RING
NOTE − If necessary, remove HCFC−22 flow control device (fixed
orifice/thermostatic expansion valve) from existing line set before
installing HFC−410A approved expansion valve and o−ring.
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.
NOTE − If the indoor unit line and set is new, skip this sec-
tion and go on to the Manifold Gauge Set section.
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 HFC−410A refrigerant. Residual mineral oil
can act as an insulator, preventing proper heat
transfer. It can also clog the expansion device, and
reduce the system performance and capacity.
Failure to properly flush the system per the in-
structions below will void the warranty.
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.
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 HFC−410A).
Flushing Procedure
1. Remove existing HCFC−22 refrigerant using the ap-
propriate procedure below (see figure 10):
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 cyl-
inder 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 refrig-
erant.
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
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 by-
pass the low pressure switches to ensure com-
plete 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 ex-
isting outdoor unit.
