Leak Testing; Evacuation & Dehydration - Lennox HS40 Series Installation Instructions Manual

To Close Liquid or Suction Line Service Valve:
1 − Remove stem cap with an adjustable wrench.
2 − Use a service wrench with a hex−head extension to
turn the stem clockwise to seat the valve. Tighten firm
ly.
3 − Replace the stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.
Five Ton Suction Line (Ball−Type) Service Valve
A ball type full service valve is used on five−ton HS40 065
units only. These suction line service valves function the
same way, the differences are in the valve's construction.
Valves are not rebuildable. If a valve has failed, it must be
replaced. A ball valve valve is illustrated in figure 6.
The ball valve is equipped with a service port. A Schrader
valve is factory installed. A service port cap is supplied to
protect the Schrader valve from contamination and assure
a leak free seal.
SUCTION LINE (BALL TYPE) SERVICE VALVE
(VALVE OPEN)
USE ADJUSTABLE WRENCH
ROTATE STEM CLOCKWISE 90_ TO CLOSE
ROTATE STEM COUNTER CLOCKWISE 90_ TO OPEN
TO OUTDOOR COIL
SERVICE
PORT
CAP
SCHRADER VALVE
FIGURE 6

Leak Testing

After the line set has been connected to the indoor and out
door units, the line set connections and indoor unit must be
checked for leaks.
WARNING
Never use oxygen to pressurize refrigeration or air
conditioning systems. Oxygen will explode on
contact with oil and could cause personal injury.
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 (6.9 to 13.8
kPa).
STEM CAP
STEM
BALL
(SHOWN OPEN)
TO INDOOR COIL
SERVICE PORT
Using an Electronic Leak Detector
IMPORTANT
Leak detector must be capable of sensing HFC re
frigerant.
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, how
ever, connecting it to the suction port helps to protect
the manifold gauge set from damage caused by high
pressure.)
2 − With both manifold valves closed, connect the cylinder
of R407C refrigerant. Open the valve on the R407C
cylinder (vapor only).
3 − Open the high pressure side of the manifold to allow
R407C into the line set and indoor unit. Weigh in a trace
amount of R407C. [A trace amount is a maximum of 2
ounces (57 g) refrigerant or 3 pounds (31 kPa) pres
sure]. Close the valve on the R407C cylinder and the
valve on the high pressure side of the manifold gauge
set. Disconnect R407C cylinder.
4 − Connect a cylinder of nitrogen with a pressure regulat
ing valve to the center port of the manifold gauge set.
5 − Adjust 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 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 line lengths). Check all joints for leaks.
Purge nitrogen and R407C mixture. Correct any leaks
and recheck.
Evacuation & 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 temperatures and
pressures present during operation of an air conditioning
system. Non−condensables and water vapor combine with
refrigerant to produce substances that corrode copper pip
ing and compressor parts.
1 −Connect the manifold gauge set to the service valve
ports as follows: low pressure gauge to suction line
service valve; high pressure gauge to liquid line ser
vice 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 vacu
um or thermocouple gauge should be used. The usual
Bourdon tube gauges are inaccurate in the vacuum
range.
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