Carrier 69NT40-561-201, Руководство по эксплуатации и обслуживанию, Страница: 84 / 117

6 − 3 T-364
h. After repairs have been made, be sure to perform a
refrigerant leak check (refer to Section 6.5), and
evacuate and dehydrate the low side (refer to
paragraph 6.6.1).
i. Check refrigerant charge (refer to Section 6.6).
6.5 REFRIGERANT LEAK CHECKING
WARNING
EXPLOSION HAZARD Failure to follow this
WARNING can result in death, serious
personal injury and / or property damage.
Never use air or gas mixtures containing
oxygen (O
2
) for leak testing or operating the
product.
Charge only with R
− 134a: Refrigerant must
conform to AHRI Standard 700
specification.
a. The recommended procedure for finding leaks in a
system is with a R-134a electronic leak detector.
Testing joints with soapsuds is satisfactory only for
locating large leaks.
b. If the system is without refrigerant, charge the system
with refrigerant 134a to build up pressure between 2.1
to 3.5 bar (30.5 to 50.8 psig). To ensure complete
pressurization of the system, refrigerant should be
charged at the compressor suction valve and the liq-
uid line service valve. Remove refrigerant cylinder
and leak-check all connections.
NOTE
Only refrigerant 134a should be used to
pressurize the system. Any other gas or vapor
will contaminate the system, which will require
additional purging and evacuation of the
system.
c. If required, remove refrigerant using a refrigerant
recovery system and repair any leaks. Check for
leaks.
d. Evacuate and dehydrate the unit. (Refer to paragraph
6.6.1.)
e. Charge unit per paragraph 6.7.1.
6.6 EVACUATION AND DEHYDRATION
6.6.1 General
Moisture is detrimental to refrigeration systems. The
presence of moisture in a refrigeration system can have
many undesirable effects. The most common are cop-
per plating, acid sludge formation, “freezing-up” of
metering devices by free water, and formation of acids,
resulting in metal corrosion.
6.6.2 Preparation
a. Evacuate and dehydrate only after pressure leak test
(refer to Section 6.5).
b. Essential tools to properly evacuate and dehydrate
any system include a vacuum pump (8 m3/hr = 5 cfm
volume displacement) and an electronic vacuum
gauge. The pump is available from Carrier
Transicold, P/N 07-00176-11. The micron gauge is
P/N 07 − 00414 − 00.
c. If possible, keep the ambient temperature above
15.6 C (60 F) to speed evaporation of moisture. If
the ambient temperature is lower than 15.6 C
(60 F), ice might form before moisture removal is
complete. Heat lamps or alternate sources of heat
may be used to raise the system temperature.
d. Additional time may be saved during a complete sys-
tem pump down by replacing the filter drier with a sec-
tion of copper tubing and the appropriate fittings.
Installation of a new drier may be performed during
the charging procedure.
É ÉÉ ÉÉ
É
4
D
S
10
8
9
É
6
7
ÂÂÂ
ÂÂÂ
ÂÂÂ
1
5
3
2
1. Liquid Service
Connection
2. Receiver
3. Compressor
4. Discharge Service
Connection
5. Suction Service
Connection
6. Vacuum Pump
7. Electronic Vacuum
Gauge
8. Manifold Gauge Set
9. Refrigerant Cylinder
10. Reclaimer
Figure 6 − 4 Refrigeration System Service
Connections
6.6.3 Complete System
NOTE
Refer to Partial System procedure for informa-
tion pertaining to partial system evacuation and
dehydration.
a. Remove all refrigerant using a refrigerant recovery
system.
b. The recommended method to evacuate and dehy-
drate the system is to connect evacuation hoses at
the compressor suction and liquid line service valve
(see Figure 6 − 4). Be sure the service hoses are
suited for evacuation purposes.