Air Purging; I Air Purging With A Vacuum Pump (For Test Run) - Technibel GRF148MR5I Technical & Service Manual

4. Air Purging

Air and moisture remaining in the refrigerant sys-
tem have undesirable effects as indicated below.
Therefore, they must be purged completely.
G pressure in the system rises
G
operating current rises
G
cooling efficiency drops
G
moisture in the air may freeze and block capil-
lary tubing
G
water may lead to corrosion of parts in the
refrigerant system
I
Air Purging with a Vacuum Pump
(for Test Run)
G
In order to protect the earth's environment, be
sure to use a vacuum pump to perform the air
purge.
(Never perform an air purge by using the refrigerant
gas cylinder or other external gas, or by using the gas
inside the outdoor unit.)
Perform the air purge for tubes A, B, C, and D. Use the
same procedures for all tubes.
In order to prevent charging errors with Air
CAUTION
Conditioner that uses R410A, the screw
diameter at the service valve charging port
has been changed. When recharging or
performing other servicing, use the special
charging hose and manifold gauge.
(1) Check that each tube (both narrow and wide
tubes) between the indoor and outdoor units have
been properly connected and all wiring for the test
run has been completed. Note that both narrow
and wide tube service valves on the outdoor unit
are kept closed at this stage.
(2) Using an adjustable wrench or box wrench,
remove the valve caps from the service valve on
both narrow and wide tubes.
(3) Connect a vacuum pump and a manifold valve
(with pressure gauges) to the service port on the
wide tube service valve. (Fig. 20).
Before using the vacuum pump
CAUTION
adapter, read the vacuum pump
adapter manual, and use the
adapter correctly.
Be sure to use a manifold valve
CAUTION
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.
Service
valve on
D
narrow
C
Service
B
valve on
wide tube
A
side
Hex wrench
(nominal size 4mm,
not provided)
With push-pin
Spindle
Screw diameter: 1/2
UNF 20 threads
Valve core
Cap nut tightening torque:
7 – 11 N·m
(70 – 110 kgf·cm)
(Tighten by hand, then use a
wrench to turn approximately 30 .)
<Structure of service valve on wide tube side>
When using a hex wrench to open the spindle, an
G
extremely small amount of refrigerant may leak.
This does not indicate a problem.
Use a hex wrench of a type to which force can be
G
easily applied.
16
Manifold gauge
(special for R410A)
High-pressure valve
Low-pressure
valve Vacuum pump
adapter
(for preventing
Leave the Lo Hi
reverse flow)
valve open.
(special for
Open
R410A)
Vacuum
pump
Charging hose
(special for R410A)
Fig. 20
Stopper
Cap tightening torque:
20 – 25 N·m
(200 – 250 kgf·cm)
(Tighten by hand, then
use a wrench to turn.)
Fig. 21