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Leak Testing the System
TO VAPOR
SERVICE VALVE
HFC−410A
MANIFOLD GAUGE SET
OUTDOOR UNIT
HIGH
LOW
NITROGEN
NOTE Normally, the high pressure hose is connected to the liquid line port. How-
ever, connecting it to the vapor port better protects the manifold gauge set from high
pressure damage.
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.
USE REGULATOR TO FLOW
NITROGEN AT 1 TO 2 PSIG
.
LINE SET AND INDOOR COIL
After the line set has been connected to the indoor unit and air conditioner, check the line set connections and
indoor unit for leaks. Use the following procedure to test for leaks:
LEAK TEST
A
Connect an HFC−410A manifold gauge set high
pressure hose to the vapor valve service port.
B
With both manifold valves closed, connect the
cylinder of HFC−410A refrigerant to the center port
of the manifold gauge set.
1
CONNECT GAUGE SET
2
TEST FOR LEAKS
A
B
NOTE Later in the procedure, the HFC−410A
container will be replaced by the nitrogen container.
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).
WARNING
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.
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 re-
frigeration lines. Oxygen, when exposed to a
spark or open flame, can cause damage by fire
and/or an explosion, that could result in person-
al injury or death.
IMPORTANT
Leak detector must be capable of sensing HFC refrigerant.
