Figure 6-4 Refrigeration System Service Connections - Carrier Transicold 69NT40-541 Series Operation And Service

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 ) for leak testing or operating the
2
product.
Charge Only With R−134a: Refrigerant must
conform to AHRI
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 3.5kg/cm@ (30 to 50psig). Remove refrigerant cyl-
inder 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.
d. Evacuate and dehydrate the unit (refer to paragraph
6.6).
e. Charge unit per paragraph 6.7.
6.6 EVACUATION AND DEHYDRATION
6.6.1 General
Moisture is the deadly enemy of refrigeration systems.
The presence of moisture in a refrigeration system can
have many undesirable effects. The most common are
copper 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 paragraph 6.5).
b. Essential tools to properly evacuate and dehydrate
any system include a vacuum pump (8m
volume displacement) and an electronic vacuum
gauge. The pump is available from Carrier Transicold
(P/N 07-00176-11).
Standard 700
3
/hr = 5cfm
6−3
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
section of copper tubing and the appropriate fittings.
Installation of a new drier may be performed during
the charging procedure.
1 2
S
13
11
 Â
12
 Â
1. Discharge Service
Valve
2. Compressor
3. Suction Service Valve
4. Receiver or Water
Cooled Condenser
5. Liquid Service Valve
6. Vacuum Pump
Figure 6-4 Refrigeration System Service
Connections
6.6.3 Complete System
a. Remove all refrigerant using a refrigerant recovery
system.
b. The recommended method to evacuate and dehy-
drate the system is to connect three evacuation
hoses (see Figure 6-4) to the vacuum pump and
refrigeration unit. Be sure the service hoses are
suited for evacuation purposes.
c. Test the evacuation setup for leaks by backseating
the unit service valves and drawing a deep vacuum
with the vacuum pump and gauge valves open. Shut
off the pump and check to see if the vacuum holds.
Repair leaks if necessary.
d. Midseat the refrigerant system service valves.
3
4
5
D
7 - BLUE
8 -YELLOW
9 - RED
6
10
7. Low Side Hose
8. Center Hose
9. High Side Hose
10. Electronic Vacuum
Gauge
11. Manifold Gauge Set
12. Refrigerant Cylinder
13. Reclaimer
T−318