# 504,465M
Page 9
Using an Electronic Leak Detector
1. Connect the high pressure hose of the manifold
gauge set to the suction valve service port. (Normally
the high pressure hose is connected to the liquid line
port; however, connecting it to the suction ports helps
to protect the manifold gauge set from damage
caused by high pressure.)
2. With both manifold valves closed, connect the cylin-
der of R410A refrigerant. Open the valve on the
R410A cylinder (vapor only).
3. Open the high pressure side of the manifold to allow
R410A into the line set and indoor unit. Weigh in a
trace amount of R410A. (A trace amount is a maxi-
mum of 2 oz. of refrigerant or 3 lbs. pressure.) Close
the valve on the R410A cylinder and the valve on the
high pressure side of the manifold gauge set. Discon-
nect the R410A cylinder.
Do not attempt to backseat this valve. At-
tempts to backseat this valve will cause snap
ring to explode from valve body under pres-
sure of refrigerant. Personal injury and unit
damage will result.
WARNING
3. Replace the stem cap. Tighten finger tight, then
tighten an additional 1/6 turn.
Leak Testing
After the line set has been connected to the indoor and
outdoor units, the line set connections and indoor unit
must be checked for leaks.
4. Connect a cylinder of nitrogen with a pressure regulat-
ing valve to the center port of the manifold gauge set.
When using high pressure gas such as nitrogen
for this purpose, be sure to use a regulator that
can control the pressure down to 1 or 2 psig.
5. Adjust nitrogen pressure to 150 psig. Open the valve
on the high side of the manifold gauge set to pressur-
ize the line set and the indoor coil.
6. After a short period of time, open a refrigerant port to
make sure that an adequate amount of refrigerant has
been added for detection (refrigerant requirements will
vary with lengths). Check all joints for leaks. Purge
nitrogen and R410A mixture. Correct any leaks and
recheck.
IMPORTANT: The leak detector must be capable of
sensing HFC refrigerant.
Evacuation and Dehydration
Evacuating the system of non-condensables is critical for
proper operation of the unit. Non-condensables are
defined as any gas that will not condense under tempera-
tures and pressures present during operation of an air
conditioning system. Non-condensables and water vapor
combine with refrigerant to produce substances that
corrode copper piping and compressor parts.
1. Connect the manifold gauge set to the service valve
ports as follows: low pressure gauge to suction line
service valve and high pressure gauge to liquid line
service valve.
IMPORTANT
– Compliant scroll compressors (as with
any refrigerant compressor) should never be used to
evacuate a refrigeration or air conditioning system.
NOTE
– A temperature vacuum gauge, mercury
vacuum, or thermocouple gauge should be used. The
usual bourdon tube gauges are inaccurate in the
vacuum range.
2. Connect the vacuum pump (with vacuum gauge) to
the center port of the manifold gauge set.
3. Open both manifold valves and start vacuum pump.
4. Evacuate the line set and indoor unit to an absolute
pressure of 23mm (23,000 microns) of mercury
(approximately 1 in. of mercury). During the early
stages of evacuation, it is desirable to close the
manifold gauge valve at least once to determine if
there is a rapid rise in absolute pressure. A rapid rise
in pressure indicates a relatively large leak. If this
occurs, the leak testing procedure must be repeated.
NOTE
– The term
absolute pressure
means the total
actual pressure with a given volume or system, above
Never use oxygen to pressurize refrigeration
or air conditioning systems. Oxygen will ex-
plode on contact with oil and could cause
personal injury or death.
WARNING
Refrigerant can be harmful if inhaled. Refriger-
ant must always be used and recovered re-
sponsibly. Incorrect or irresponsible use of
refrigerant can result in personal injury or
death.
WARNING
