Page 12
505328M 06/09
WARNING
Fire, Explosion and Personal Safety
Hazard.
Failure to follow this warning could
result in damage, personal injury or
death.
Never use oxygen to pressurize or
purge refrigeration lines. Oxygen,
when exposed to a spark or open
flame, can cause damage by fire and/
or an explosion, that could result in
personal injury or death.
1. Connect an HFC−410A manifold gauge set high
pressure hose to the vapor valve service port.
(Normally, the high pressure hose is connected to the
liquid line port; however, connecting it to the vapor port
better protects the manifold gauge set from high
pressure damage.)
2. With both manifold valves closed, connect the cylinder
of HFC−410A refrigerant to the center port of the
manifold gauge set. Open the valve on the HFC−410A
cylinder (vapor only).
3. Open the high pressure side of the manifold to allow
HFC−410A into the line set and indoor unit.
4. Weigh in a trace amount of HFC−410A.
[A trace
amount is a maximum of two ounces (57 g) refrigerant
or three pounds (31 kPa) pressure].
5. Close the valve on the HFC−410A cylinder and the
valve on the high pressure side of the manifold gauge
set.
6. Disconnect the HFC−410A cylinder.
7. Connect a cylinder of dry nitrogen with a pressure
regulating valve to the center port of the manifold
gauge set.
8. Adjust dry nitrogen pressure to 150 psig (1034 kPa).
9. Open the valve on the high side of the manifold gauge
set in order to pressurize the line set and the indoor unit.
10. After a few minutes, open one of the service valve
ports and verify that the refrigerant added to the
system earlier is measurable with a leak detector
.
11. After leak testing disconnect gauges from service
ports.
Removing Service Valve Port Core
Remove both of the outdoor unit’s service port cores (liquid
and vapor) as illustrated in figure 21.
REMOVE SERVICE
PORT CAP
REMOVE PORT CORE
OUTDOOR UNIT
SERVICE VALVE
Figure 21. Typical Service Valve Port Core Removal
Flushing Existing System
IMPORTANT
The line set and indoor unit coil must be flushed
with at least the same amount of clean refrigerant
that previously charged the system. Check the
charge in the flushing cylinder before proceeding.
IMPORTANT
If this unit is being matched with an approved line
set or indoor unit 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 installation. 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
instructions below will void the warranty.
CAUTION
This procedure should not be performed on
systems which contain contaminants (Example:
compressor burn out).
IMPORTANT
The Environmental Protection Agency (EPA)
prohibits the intentional venting of HFC refrigerants
during maintenance, service, repair and disposal of
appliance. Approved methods of recovery,
recycling or reclaiming must be followed.
If new lines are used then proceed to
Installing New
Refrigerant Metering Device.
Otherwise proceed with the
following procedure.
