Air Purging - Sanyo SAP-KCRV243GJH Technical & Service Manual

7-4. Air Purging

Air and moisture remaining in the refrigerant system
have undesirable effects as indicated below. There-
fore, they must be purged completely.
pressure in the system rises
operating current rises
cooling efficiency drops
moisture in the air may freeze and block capillary
tubing
water may lead to corrosion of parts in the refriger-
ant system
Air Purging with a Vacuum Pump
(for Test Run)
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.)
CAUTION
(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).
CAUTION
CAUTION
In order to prevent charging
errors with A/C 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.
Before using the vacuum pump
adapter, read the vacuum pump
adapter manual, and use the
adapter correctly.
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 closed.
Service valve
on narrow
tube side
Service
valve on
wide tube
side
Hex wrench
(nominal size 4 mm, not provided)
With push-pin
CRV243
Service
valve on
narrow
Service
valve on
wide tube
side
Hex wrench
(nominal size 4 mm,
With push-pin
not provided)
CRV303
Screw diameter: 1/2 (243 type)
Spindle
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
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
easily applied.
34
Manifold gauge
(special for R410A)
Low-
High-pressure valve
pressure
valve
Vacuum pump
adapter
Leave the
Lo Lo Lo Lo Lo Lo Lo Hi Hi
(for preventing
valve open.
reverse flow)
Open (special for
R410A)
Vacuum
pump
Charging hose
(special for R410A)
Fig. 20a
Manifold gauge
(special for R410A)
High-pressure valve
Low-pressure
Vacuum pump
valve
adapter
(for preventing
Leave the
Lo Lo Lo Lo Lo Lo Lo Hi Hi
reverse flow)
valve open.
(special for
Open R410A)
Charging hose
(special for R410A)
Fig. 20b
5/8 (303 type)
Stopper
Cap tightening torque:
20-25 N-m
(200-250 kgf-cm)
(Tighten by hand, then
use a wrench to turn.)
Fig. 21
Vacuum
pump