Page 11
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.
Disconnect all power to the existing outdoor unit. Re-
fer to 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.
2 − Remove the existing outdoor unit. Set the new R410A
unit and follow the brazing connection procedure
which begins on the previous page to make line set
connections.
DO NOT install provided R410A
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.
3 − Remove the existing refrigerant flow control orifice or
thermal expansion/check valve before continuing with
flushing procedures. The existing devices are not ap-
proved for use with R410A refrigerant and may pre-
vent proper flushing. Use a field−provided fitting to re-
connect the lines.
IMPORTANT
The line set and indoor coil must be flushed with at
least the same amount of clean refrigerant that pre-
viously charged the system. Check the charge in
the flushing cylinder before proceeding.
Flushing Connections
Figure 12
LOW
PRESSURE
HIGH
PRESSURE
VAPOR LINE
SERVICE VALVE
Indoor Coil
HPXA15 Unit
GAUGE MANIFOLD
Recovery Machine
Inverted R22 Cylinder
(Contains clean R22 to
be used for flushing)
LIQUID LINE
SERVICE VALVE
INLET
DISCHARGE
TANK RETURN
CLOSED
OPENED
Existing
EXISTING VAPOR LINE
EXISTING LIQUID LINE
RECOVERY
CYLINDER
NOTE − The inverted R22 cylinder must con-
tain at least the same amount of refrigerant
as was recovered from the existing system.
