Panasonic U-200PE1E8 Installation Instructions Manual Download

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8. LEAK TEST, EVACUATION AND

ADDITIONAL REFRIGERANT CHARGE

Perform an air-tightness test for this package A/C. Check that
there is no leakage from any of the connections.

Air and moisture in the refrigerant system may have undesirable
effects as indicated below.

●

pressure in the system rises

●

operating current rises

●

cooling (or heating) efficiency drops

●

moisture in the refrigerant circuit may freeze and block

capillary tubing

●

water may lead to corrosion of parts in the refrigerant system

Therefore, the indoor unit and tubing between the indoor and
outdoor unit must be leak tested and evacuated to remove any
noncondensables and moisture from the system. (Figs. 8-1 and
8-2)

Fig. 8-1

Fig. 8-2

■

Air Purging with a Vacuum Pump (for Test Run)
Preparation

Check that each tube (both liquid and gas tubes) between the
indoor and outdoor units has been properly connected and all
wiring for the test run has been completed. Remove the valve
caps from both the gas and liquid service valves on the outdoor
unit. Note that both liquid and gas tube service valves on the
outdoor unit are kept closed at this stage. (Fig. 8-3)

Fig. 8-3

●

The refrigerant charge at the time of shipment is only

guaranteed sufficient for a tubing length of up to 30 m. The
tubing may exceed this length, up to the maximum permitted
length; however, an additional charge is necessary for
the amount that the tubing exceeds 30 m. (No additional
refrigerating machine oil is needed.)

8-1. Leak Test

(1) With the service valves on the outdoor unit closed, remove

the 7.94 mm flare nut and its bonnet on the gas tube
service valve. (Save for reuse.)

(2) Attach a manifold valve (with pressure gauges) and dry

nitrogen gas cylinder to this service port with charge
hoses.

CAUTION

Use a manifold valve for air purging. If it is not available,
use a stop valve for this purpose. The “Hi” knob of the
manifold valve must always be kept closed.

(3) Pressurize the system up to 4.15 MPa (42 kgf/cm

G) with

dry nitrogen gas and close the cylinder valve when the
gauge reading reaches 4.15 MPa (42 kgf/cm

G). Then,

test for leaks with liquid soap.

CAUTION

To avoid nitrogen entering the refrigerant system in a
liquid state, the top of the cylinder must be higher than
the bottom when you pressurize the system. Usually, the
cylinder is used in a vertical standing position.

(4) Do a leak test of all joints of the tubing (both indoor and

outdoor) and both gas and liquid service valves. Bubbles
indicate a leak. Wipe off the soap with a clean cloth after a
leak test.

(5) After the system is found to be free of leaks, relieve the

nitrogen pressure by loosening the charge hose connector
at the nitrogen cylinder. When the system pressure is
reduced to normal, disconnect the hose from the cylinder.

Manifold gauge

Vacuum pump

Outlet

Inlet

Manifold valve

Pressure
gauge

Cylinder
valve

Nitrogen gas cylinder
(In vertical standing
position)

Charge hose

Open

Gas tube

Liquid tube

Outdoor unit

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2011/02/23 13:37:52

8-2. Evacuation

Be sure to use a vacuum pump that includes a function for
prevention of back-flow, in order to prevent back-flow of pump
oil into the unit tubing when the pump is stopped.

●

Perform vacuuming of the indoor unit and tubing.

Connect the vacuum pump to the gas tube valve and apply
vacuum at a pressure of –101kPa (–755 mmHg, 5 Torr) or
below.
Continue vacuum application for a minimum of 1 hour after
the pressure reaches –101kPa (–755 mmHg, 5 Torr).

(1) Attach the charge hose end described in the preceding

steps to the vacuum pump to evacuate the tubing and
indoor unit. Confirm that the “Lo” knob of the manifold
valve is open. Then, run the vacuum pump.

(2) When the desired vacuum is reached, close the “Lo”

knob of the manifold valve and turn off the vacuum pump.
Confirm that the gauge pressure is under –101 kPa (–755
mmHg, 5 Torr) after 4 to 5 minutes of vacuum pump
operation. (Fig. 8-4)

CAUTION

Use a cylinder specifically designed for use with R410A.

Fig. 8-4

8-3. Charging Additional Refrigerant

●

Charging additional refrigerant (calculated from the liquid

tube length as shown in “Amount of additional refrigerant
charge”) using the liquid tube service valve. (Fig. 8-5)

●

Use a balance to measure the refrigerant accurately.

●

If the additional refrigerant charge amount cannot be

charged at once, charge the remaining refrigerant in liquid
form by using the gas tube service valve with the system in
Cooling mode at the time of test run. (Fig. 8-6)

* If an additional refrigerant charge has been performed, list the

refrigerant tubing length and amount of additional refrigerant
charge on the product label (inside the panel).

R410A

Fig. 8-5

Fig. 8-6

8-4. Finishing the Job

(1) With a hex wrench, turn the liquid tube service valve stem

counterclockwise to fully open the valve.

(2) Turn the gas tube service valve stem counterclockwise to

fully open the valve.

CAUTION

To avoid gas from leaking when removing the charge hose,
make sure the stem of the gas tube is turned all the way
out (“BACK SEAT”) position.

(3) Loosen the charge hose connected to the gas tube service

port (7.94 mm) slightly to release the pressure, and then
remove the hose.

(4) Replace the 7.94 mm flare nut and its bonnet on the gas

tube service port and fasten the flare nut securely with an
adjustable wrench or box wrench. This process is very
important to prevent gas from leaking from the system.

(5) Replace the valve caps at both gas and liquid service

valves and fasten them securely.

Manifold valve

Pressure
gauge

Vacuum pump

Open

Gas tube

Liquid tube

Outdoor unit

Manifold valve

Pressure
gauge

Valve