Allied Air Enterprises 4AC16LT - Manual (Page 7)

506467-01 Issue 1008 Page 7
Flushing Existing Line Set and Indoor Coil
This procedure should not be performed on systems
which contain contaminants, such as compressor
burn out.
Flushing Procedure
IMPORTANT: The line set and/or indoor coil must be
flushed with at least the same amount of refrigerant that
previously charged the system. Check the charge in the
flushing cylinder before flushing the unit.
1. Remove existing R22 refrigerant using the appropriate
procedure.
If the existing outdoor unit is not equipped with shutoff
valves, or if the unit is not operational AND the existing
R22 refrigerant will be used to flush the system:
Disconnect all power to the existing outdoor unit.
Connect the existing unit, a clean recovery cylinder, and
the recovery machine according to the instructions
provided with the recovery machine. Remove all R22
refrigerant from the existing system. Refer to the
gauges after shutdown to confirm that the entire system
is completely void of refrigerant. Disconnect the liquid
and suction lines from the existing outdoor unit.
If the existing outdoor unit is equipped with manual
shutoff valves AND new R22 refrigerant will be used
to flush the system:
Start the existing R22 refrigerant system in cooling mode
and close the liquid line valve. Pump all the existing R22
refrigerant back into the outdoor unit.
Required Equipment
The following equipment is needed to flush the existing
line set and indoor coil (see Figure 8): Two clean R22
recovery bottles, an oil-less recovery machine with a
“pump down” feature, and two sets of gauges (one for use
with R22 and one for use with R410A).
Figure 8
Flushing Connections
Note: The inverted R22 cylinder must contain
at least the same amount of refrigerant
as was recovered from the existing
system.
When flushing existing line set and/or indoor
coil, be sure to empty all existing traps. 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 system as
explained in these instructions will void warranty.
CAUTION