Leak Test Line Set And Indoor Coil - Lennox 14HPX-036-230-17 Installation And Service Procedure

IMPORTANT
The Environmental Protection Agency (EPA) prohibits the
intentional venting of
maintenance, service, repair and disposal of appliance.
Approved methods of recovery, recycling or reclaiming
must be followed.
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.
1
CONNECT GAUGE SET
A Connect an HFC-410A manifold gauge set high pressure
hose to the vapor valve service port.
NOTE — 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.
B With both manifold valves closed, connect the cylinder of
HFC-410A refrigerant to the center port of the manifold gauge
set.
NOTE — Later in the procedure,
the HFC-410A container will be
replaced by
container.
2
TEST FOR LEAKS
After the line set has been connected to the indoor and outdoor units, check the line set connections and indoor unit for leaks. Use the
following procedure to test for leaks:
A 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).
B Open the high pressure side of the manifold to allow HFC-410A into the line set and indoor unit. 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]. Close the valve on the HFC-410A cylinder
and the valve on the high pressure side of the manifold gauge set. Disconnect the HFC-410A cylinder.
C Connect a cylinder of dry nitrogen with a pressure regulating valve to the center port of the manifold gauge set.
D Adjust dry nitrogen pressure to 150 psig (1034 kPa). Open the valve on the high side of the manifold gauge set in order to pressurize the line set
and the indoor unit.
E 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.
F After leak testing disconnect gauges from service ports.
HFC refrigerants
the nitrogen
NITROGEN

Leak Test Line Set and Indoor Coil

during
Leak detector must be capable of sensing HFC
refrigerant.
Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.
Failure to follow this warning may result in personal injury
or death.
LOW
B
HFC-410A
Figure 13. Leak Test
Page 22
WARNING
When using a high pressure gas such as
dry nitrogen to pressurize a refrigeration or
air conditioning system, use a regulator
that can control the pressure down to 1 or
2 psig (6.9 to 13.8 kPa).
IMPORTANT
WARNING
HIGH
MANIFOLD GAUGE SET
OUTDOOR UNIT
A
TO VAPOR
SERVICE VALVE