Thermo King MD-MT, Operator'S Manual

Page: 126 / 192

Refrigeration Service Operations
126
Equipment Recommendations For
Use With R-404A
Dedicated Equipment
Vacuum Pumps
When evacuating, a two stage three or five CFM
pump is recommended. It is also recommended
that dry nitrogen be used first. Ideally, a new
vacuum pump should be used and dedicated for
use with R-404A systems because residual
refrigerants may remain in used vacuum pumps.
Pumps used with other Thermo King refrigerants
may be used but extreme care should be taken to
prevent contamination of R-404A systems with
other refrigerants.
An oil filter TK P/N 66-7800 is added to the
vacuum pump.
The Thermo King Evacuation Station is
recommended. This station is available from
service parts under part number 204-725. See
Truck and Trailer Service Bulletin T&T 061 for
additional details.
Use only recommended vacuum pump oils and
change oil after every major evacuation. Vacuum
pump oils are highly refined and the use of
contaminated oils will prevent the desired vacuum
from being obtained. Failure to follow these
recommendations may result in conditions that
will destroy the vacuum pump.
Gauge Manifold Sets
Gauge manifold sets that show the correct
pressure-temperature relationship should be used.
Gauge manifolds and manifold hoses used with
other Thermo King refrigerants maybe used but
extreme care should be taken to prevent
contamination of the R-404A systems with other
refrigerants. Purge manifold and hoses with dry
nitrogen before using. Never use equipment that
may be contaminated with automotive type
polyalkylene glycol (PAG) oils.
System Clean-up
Existing clean up devices such as suction line
filters and compressor oil filters may be used if
they are thoroughly cleaned and new filter
elements are installed. All standard compressor
oils must be removed from clean-up devices to
prevent contamination of R-404A systems.
Dangerous contamination will result if other
refrigerants or standard oils are introduced to
R-404A systems.
NOTE: For additional information on parts and
supplies, consult your local Thermo King dealer
and Thermo King Tool Catalog.
Refrigerant Recovery
Present systems can be adapted to the recovery of
R-404A but should be dedicated to the recovery of
these refrigerants. Consult the manufacturer of
your recovery equipment for details.
Oil Filter Maintenance
X214 compressors using R-404A are equipped
with a bypass oil filter. To ensure the system stays
clean, the oil filter and filter-drier must be
changed every 2 years or whenever a major
service procedure has been performed.
CAUTION: Equipment that has been used
with other refrigerants MUST NOT be
used with R-404A refrigerants. Mixing
R-404A with other refrigerants will cause
contamination of the refrigerant. Using
contaminated refrigerant will cause
system failure.