6-4
Service Procedures
Refrigeration System Diagnosis and Service
CSR-20 & CSR-40, September 1999
Hermetic Refrigeration System Service
Procedures
• To connect a gauge manifold set or other service tools to the
the refrigeration system, special piercing type service valves
must be attached to the discharge and suction line process
tubes. These process tubes are located in the compressor
compartment.
• When service or maintenance is complete, the hermetic
refrigeration system must be returned to normal. The suction
and discharge line process tubes must be carefully sealed and
the service valves must be removed from the system.
Service Tools
CAUTION: When servicing Thermo King R-404A
refrigeration systems, use only those service tools
(i.e., vacuum pump, refrigerant recovery equipment,
gauge hoses, and gauge manifold set) certified for
and dedicated to R-404A refrigerant and Polyol Ester
based compressor oils. Residual non-HFC refriger-
ants or non-Ester based oils will contaminate HFC
systems.
Refrigeration System Service Valves
To service the refrigeration system on CSR hermetic units,
special piercing type service valves must be attached to the
discharge and suction line process tubes.
NOTE: Special fittings may also be needed to con-
nect gauge hoses and other service tools to the spe-
cial piercing type service access valves.
Refrigerant Recovery
Use only refrigerant recovery equipment approved for and
dedicated to R-404A recovery.
Leak Detection
Leaks can be detected with the use of soap bubbles and with
Halogen leak detectors such as model H10G, P/N 204-712 or
model H10N, P/N 204-756 (portable).
Gauge Manifold Set
The gauge manifold set should be dedicated for use with R-
404A only. Piercing type service valves require that the gauge
manifold set connect to 1/4” flare fittings:
• Use Gauge Manifold, P/N 204-526, and gauge hoses with
self-sealing, 1/4 in. fittings:
- P/N 204-761, 6 ft (1.8 m) blue hose
- P/N 204-762, 6 ft (1.8 m) red hose
- P/N 204-763, 6 ft (1.8 m) yellow hose, or
• Use a Gauge Manifold set equipped with 1/4” gauge hoses
with R-134a suction and discharge couplers, plus:
- P/N 66-7181, Suction adapter, 1/4 in. male flare fitting
to 1/2 in. Acme thread fitting
- P/N 66-7179, Discharge adapter, 1/4 in. male flare fitting
to 1/2 in. Acme thread fitting
Vacuum Pump
A two-stage (P/N 204-725), three-stage or five-stage pump is
recommended for evacuation. Purging the system with dry
nitrogen is recommended before evacuation. Because residual
refrigerant may be present in used vacuum pumps, a new vacu-
um pump should be used and dedicated strictly as an R-404A
refrigerant pump. Use only recommended vacuum pump oils
and change oil after every major evacuation.
Because vacuum pump oils are highly refined to obtain
low vacuums, failure to follow these recommendations may
result in acidic conditions that will destroy the pump.
System Cleanup
Cleanup devices such as suction line filters and compressor oil
filters may be used if they are properly cleaned and new filters
and cartridges are used. All standard petroleum and synthetic
compressor oils must be removed to prevent the contamination
of R-404A systems.
Recommended Solders
When repairing solder connections, use the same solder that
was used in the manufacturing process:
• Copper to copper, use 15% Silver Solder, P/N 203-364
• Copper to brass or steel, use 35% Silver Solder, P/N 203-366
Use flux, P/N 203-365, with both 15% and 35% silver sol-
der. Other types of leaks such as punctures in tubes and leaks
in coils can best be repaired using 15% silver solder, P/N 203-
364 (with flux, P/N 203-365).
NOTE: Thermo King recommends that service proce-
dures use the use the same solder on connections
that was used in the manufacturing process.
Therefore, technicians should obtain the recom-
mended solder and flux from Thermo King.
Compressor Oil Acid Test
Perform an oil acid test (oil test kit P/N 203-457) whenever a
unit has a substantial refrigerant loss, a noisy compressor or
dark/dirty oil.
