4
1. Connect the vacuum pump, high vacuum manifold
set, thermocouple vacuum gauge and charging cyl-
inder as shown in Figure 2. Be sure all valves are
fully closed.
2. Confirm proper pump and gauge operation. Open
the shutoff valve leading to the vacuum pump (C).
Start the pump. When the gauge manifold (low side)
reading drops to about 29 inches of vacuum, open
the valve to the thermocouple vacuum gauge (D).
Continue evacuation until the gauge reads 250 mi-
crons or less.
A. HIGH SIDE VALVE
B. LOW SIDE VALVE
C. VACUUM PUMP
D. THERMOCOUPLE GAUGE
E. MANIFOLD GAUGE
F. CHARGING CYLINDER
C
A
B
E
D
HIGH VACUUM PUMP
LARGE DIAMETER
BRAIDED VACUUM
HOSES
TO
RELATED
GAUGE
PORTS OF
COND. UNIT
HIGH VACUUM
MANIFOLD
LOW SIDE
GAUGE
HIGH SIDE
GAUGE
DIAL-A-CHARGE
CHARGING CYLINDER
THERMOCOUPLE
VACUUM
GAUGE
F
Figure 2
3. To avoid potential gauge damage due to “pegging
the meter”, close the valve to the thermocouple
vacuum gauge (D).
4. Open the high side (B) and low (A) side valves on the
manifold gauge. Keeping the valve on the charging
cylinder closed (F), open the valve on the manifold
gauge (E) leading to the cylinder.
5. Evacuate the system to about 29 inches of vacuum
as measured by the manifold gauge (low side).
6. Open the valve to the thermocouple vacuum gauge
(D) and evacuate until the gauge reads 250 microns
or less.
7. Close the valve to the vacuum pump. Wait five
minutes, then check the pressure on the thermo-
couple vacuum gauge:
a. If the pressure is not more than 1500 microns, the
system is leak-free and properly evacuated. Pro-
ceed to Step 8.
b. If the pressure rises, but holds at about 5000
microns, moisture and noncondensables are still
present. Open the valve to the
vacuum pump, and go back to Step 6.
c. If the pressure rises above 5000 microns, a leak is
present. Repeat Section II,
Leak Testing.
8. Close the valve to the thermocouple vacuum gauge.
Close the valve to the vacuum pump. Shut off the
pump.
LEAK TESTING
WARNING
To avoid the risk of fire or explosion, never
use oxygen, high pressure air or flammable
gasses for leak testing of a refrigeration
system.
1. Be sure both hand valves on the gauge manifold are
closed relative to the center port (i.e., turned in all the
way.) Attach this gauge manifold to the service valves
on the unit. Do not open the unit service valves. Do
not use refrigerant from the unit for leak testing - it has
been precisely measured at the factory for optimum
performance.
WARNING
To avoid possible explosion, the line from
the nitrogen cylinder must include a
pressure regulator and a pressure relief
valve. The pressure relief valve must be
set to open at no more than 150 psig.
2. Connect a cylinder of dry nitrogen to the center port on
the gauge manifold.
3. Open the hand valve a minimal amount on the line
coming from the nitrogen cylinder.
4. Open the high pressure valve on the manifold gauge.
Pressurize the refrigerant lines and the indoor coil to
150 psig (1034 kPA). To reach 150 psig, you may
need to further open the hand valve on the nitrogen
cylinder. Once 150 psig has been reached, close the
valve on the nitrogen cylinder and disconnect it from
the manifold gauge.
WARNING
To avoid possible explosion or equipment
damage, do not exceed 150 psig when
pressure testing.
5. Place a soapy solution on all connections and joints
and check for bubbles. If bubbles are seen, you have
a leak. Mark these locations.
NOTE: If you plan to use an electronic leak detector,
add a trace of R-22 to the system (if permitted by
current EPA regulations).
6. Using the manifold gauge, carefully release the nitro-
gen from the system. Check for leaks. If leaks are
found, repair them and repeat steps 1 through 6. If no
leaks are found, proceed to system evacuation.
SYSTEM EVACUATION
NOTE: Evacuate the indoor (ID) coil and line sets prior to
releasing charge from the outdoor (OD) unit into the system.
