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- 33 -

■

Pour a glass of water on the drain pan.

■

Ensure the water flows through the drain hose of
the indoor unit without any leakage and goes out
the drain exit.

■

The drain hose should point downward for easy
drain flow.

■

Do not make drain piping.

Right side panel

Downward slope

Do not raise

Accumulated
drain water

Tip of drain hose 
dipped in water

Air

Waving

Water
leakage

Water
leakage

Ditch

Less than 
50mm gap

Water
leakage

Lower panel

Left side panel

- 34 -

■

If you want to connect an additional drain hose,
the end of the drain outlet should be routed above
the ground. Secure the drain hose appropriately.

■

Tape the piping, drain hose and connecting cable
from down to up.

■

Secure the tapped piping along the exterior wall
using saddle or equivalent.

■

Tape the piping and connecting cable from down
to up.

■

Secure the taped piping along the exterior wall.
Form a trap to prevent water entering the room.

■

Fix the piping onto the wall by saddle or equiva-
lent.

;;

;;

Taping

Drain

hose

Pipings

Connecting

cable

Trap is required to prevent water
from entering into electrical parts.

Seal small openings
around pipings with a
gum type sealer.

Trap is required to prevent water from entering 
into electrical parts.

Seal a small opening
around the pipings
with gum type sealer.

Drain hose

Taping

Pipings

Connecting
cable

Power supply
cord

;;

;;

Seal a small opening 
around the pipings 
with gum type sealer.

Trap

Trap

Seal a small opening 
around the pipings 
with gum type sealer.

Trap

Trap

- 35 -

Air and moisture remaining in the refrigerant system
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 refrig-
eration 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.

■

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

■

Connect the manifold valve(with pressure gauges)
and dry nitrogen gas cylinder to this service port
with charge hoses.

■

Pressurize the system to no more than 150 P.S.I.G.
with dry nitrogen gas and close the cylinder valve
when the gauge reading reached 150 P.S.I.G.
Next, test for leaks with liquid soap.

■

Do a leak test of all joints of the tubing(both indoor
and outdoor) and both gas and liquid side service
valves. 
Bubbles indicate a leak. Be sure to wipe off the
soap with a clean cloth.

■

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.

Be sure to 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 close.

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

Lo

Hi

Indoor unit

Indoor unit

Outdoor unit

Outdoor unit

Manifold valve

Charge hose

Nitrogen gas
cylinder(in vertical
standing position)

Pressure 
gauge

- 36 -

■

Connect the charge hose end described in the 
preceding steps to the vacuum pump to evacuate
the tubing and indoor unit.
Confirm the "Lo" knob of the manifold valve is
open. Then, run the vacuum pump.
The operation time for evacuation varies with tubing
length and capacity of the pump. The following
table shows the time required for evacuation.

■

When the desired vacuum is reached, close the
"Lo" knob of the manifold valve and stop the 
vacuum pump.

■

With a service valve wrench, turn the valve stem
of liquid side valve counter-clockwise to fully
open the valve.

■

Turn the valve stem of gas side valve
counter-clockwise to fully open the valve.

■

Loosen the charge hose connected to the gas
side service port slightly to release the pressure,
then remove the hose.

■

Replace the flare nut and its bonnet on the gas
side service port and fasten the flare nut securely
with an adjustable wrench. This process is very
important to prevent leakage from the system.

■

Replace the valve caps at both gas and liquid
side service valves and fasten them tight.
This completes air purging with a vacuum pump. 
The air conditioner is now ready to test run.

(1) Remove the caps from the gas side and liquid side valves.
(2) Remove the service-port cap from the gas side valve.
(3) To open the gas side valve turn the valve stem counter-

clockwise approximately 90°, wait for about 2~3 sec, and
close it.

(4) Apply a soap water or a liquid neutral detergent on the

indoor unit connection or outdoor unit connections by a
soft brush to check for leakage of the connecting points of
the piping.

(5) If bubbles come out, the pipes have leakage.

Gas side

Liquid side

Cap

Hexagonal wrench

3-way valve

(Open)

3-way valve

(Close)

Required time for evacuation 

when 30 gal/h vacuum pump is used

10 min. or more

15 min. or more

If tubing length is less

than 10m (33 ft).

If tubing length is longer

than 10m (33 ft).

Indoor unit

Outdoor unit

Lo

Hi

Manifold valve

Vacuum pump

Pressure 
gauge

Open

Close

Indoor unit

Outdoor unit