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Vapor Line (Ball Type) Service Valve
A ball-type full service valve is used on 12HPB. Valves
are not rebuildable. If a valve has failed it must be replaced. A
ball valve is illustrated in figure 15.
The ball valve is equipped with a service port. A schrader
valve is factory installed. A service port cap is supplied to pro-
tect the schrader valve from contamination and assure a
leak free seal.
SUCTION LINE (BALL TYPE) SERVICE VALVE
(VALVE OPEN)
FIGURE 15
SCHRADER CORE
SERVICE PORT
SERVICE
PORT
CAP
STEM CAP
INLET
(FROM INDOOR COIL)
OUTLET
(TO
COMPRESSOR)
STEM
USE ADJUSTABLE WRENCH
ROTATE STEM CLOCKWISE 90_ TO CLOSE
ROTATE STEM COUNTER-CLOCKWISE 90_ TO OPEN
BALL
(SHOWN OPEN)
III − CHARGING
The unit is factory−charged with the amount of R−22 refrig-
erant indicated on the unit rating plate. This charge is
based on a matching indoor coil and outdoor coil with a 15
foot (4.5 m) line set. For varying lengths of line set, refer to
table 5 for refrigerant charge adjustment. A blank space is pro-
vided on the unit rating plate to list actual field charge.
IMPORTANT
If line length is greater than 15 feet (4.5 m) add this
amount. If line length is less than 15 feet (4.5 m),
subtract this amount.
LIQUID LINE
1/4 in. (6 mm)
5/16 in. (8mm)
3/8 in. (10 mm)
TABLE 5
Ounce per 5 foot (ml per mm) adjust
from 15 foot (4.5 m) line set*
1 ounce per 5 feet (30 ml per 1524 mm)
*If line set is greater than 15 ft. (4.5 m) add this amount. If line set
is less than 15 feet (4.5 m) subtract this amount
SET DIAMETER
2 ounce per 5 feet (60 ml per 1524 mm)
3 ounce per 5 feet (90 ml per 1524 mm)
Units are designed for line sets up to 50 feet (15.2 m).
Consult Lennox Refrigerant Piping Manual for line sets
over 50 feet (15.2 m).
A − Pumping Down System
CAUTION
Deep vacuum operation (operating compressor
at 0 psig or lower) can cause internal fusite
arcing resulting in a damaged or failed
compressor. This type of damage will result in
denial of warranty claim.
The system may be pumped down when leak checking the
line set and indoor coil or making repairs to the line set or
indoor coil.
1− Attach gauge manifold.
2− Front seat (close) liquid line valve.
3− Start outdoor unit.
4− Monitor suction gauge. Stop unit when 0 psig is reached.
5− Front seat (close) suction line valve.
B − Leak Testing (To Be Done
Before Evacuating)
1− Attach gauge manifold and connect a drum of dry nitro-
gen to center port of gauge manifold.
2− Open high pressure valve on gauge manifold and
pressurize line set and indoor coil to 150 psig (1034
kPa).
3− Check lines and connections for leaks.
NOTE-The preferred method is to use an electronic leak or
Halide detector. Add a small amount of R22 (3 to 5 psig
[20kPa to 34kPa]) then pressurize with nitrogen to 150 psig.
4− Release nitrogen pressure from the system, correct any
leaks and recheck.
DANGER
When using dry nitrogen, a pressure reducing reg-
ulator must be used to prevent excessive pressure
in gauge manifold, connecting hoses, and within
the system. Regulator setting must not exceed 150
psig (1034 kpa). Failure to use a regulator can
cause equipment failure resulting in injury or
death.
C − Evacuating the System
1− Attach gauge manifold. Connect vacuum pump (with vac-
uum gauge) to center port of gauge manifold. With both
manifold service valves open, start pump and evacuate
indoor coil and refrigerant lines.
IMPORTANT
A temperature vacuum gauge, mercury vacuum
(U−tube), or thermocouple gauge should be used.
The usual Bourdon tube gauges are not accurate
enough in the vacuum range.
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