Air Purging - Panasonic U-8ME1E8 Mode D'emploi

SUPPLEMENT
5-4. Taping the Tubes
(1) At this time, the refrigerant tubes (and electrical wiring if
local codes permit) should be taped together with armoring
tape in 1 bundle. To prevent the condensation from
overflowing the drain pan, keep the drain hose separate
from the refrigerant tubing.
(2) Wrap the armoring tape from the bottom of the outdoor
unit to the top of the tubing where it enters the wall. As you
wrap the tubing, overlap half of each previous tape turn.
(3) Clamp the tubing bundle to the wall, using 1 clamp approx.
each meter. (Fig. 5-10)
N OTE
Do not wind the armoring tape too tightly since this will
decrease the heat insulation effect. Also ensure that the
condensation drain hose splits away from the bundle and drips
clear of the unit and the tubing.
5-5. Finishing the Installation
After finishing insulating and taping over the tubing, use sealing
putty to seal off the hole in the wall to prevent rain and draft
from entering. (Fig. 5-11)
Clamp
Drain hose
Insulated tubes
Fig. 5-10
Apply putty here
Tubing
Fig. 5-11
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6. AIR PURGING

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.
■ 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 have 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.
Leak test
(1) With the service valves on the outdoor unit closed, remove
the 1/4 in. 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.
Use a manifold valve for air
purging. If it is not available,
use a stop valve for this
CAUTION
purpose. The "Hi" knob of the
manifold valve must always be
kept closed.
(3) Pressurize the system to no more than 3.8 MPa with dry
nitrogen gas and close the cylinder valve when the gauge
reading reaches 3.8 MPa. Then, test for leaks with liquid
soap.
To avoid nitrogen entering the
refrigerant system in a liquid
state, the top of the cylinder
CAUTION
must be higher than the bottom
when you pressurize the
system. Usually, the cylinder
is used in a vertical standing
position.
Manifold gauge
Fig. 6-1
Vacuum pump
Outlet
Inlet
Fig. 6-2
Manifold valve
Pressure
Lo Hi
gauge
Charge hose
Cylinder
valve
Nitrogen gas cylinder
(In vertical standing
position)
Open
Gas
tube
Close
Open
Outdoor unit
Liquid
tube
Close
Open
Balance
tube
Close
Fig. 6-3
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