Thermo King KD-II SR, Manual

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Refrigeration Service Operations (Rev. 04/03)
117
R-134a and R-404A
The refrigeration industry has introduced two new
refrigerants called R-134a and R-404A. Both refrigerants
are classified as a Hydrofluorocarbon (H.F.C.) because they
contain hydrogen, fluorine and carbon. They do not contain
chlorine. R-134a was developed as a replacement for R-12
and R-404A was developed as a replacement for R-502.
Both R-12 and R-502 contain chlorine that presents a
hazard to the environment.
The pressure temperature relationship of R-134a is similar
to that of R-12 and the pressure temperature relationship of
R-404A is similar to that of R-502.
The capacities of these new refrigerants are similar for box
temperatures above 0 F (-18 C). At temperatures below 0 F
(-18 C), H.F.C. refrigerant capacities are slightly less than
CFC refrigerants.
Unit Identification
Units charged with R-134a or R-404A are identified by the
following methods:
1. HFC-134a or HFC-404A will be stamped on the unit’s
serial plate.
2. “HFC” may be incorporated in the model designation
on the sides of the unit such as “KD-II SR HFC”.
3. Decals will be applied to unit as shown below.
Availability
Refrigerants 134a and 404A are available from wholesalers.
The price will depend upon the quantity purchased. Thirty
(30), 50 and 125 pound containers are available. When
purchasing R-134a in 30 pound or 50 pound containers,
specify industrial containers with 1/4 inch flare fittings to
receive containers with 1/4 inch flare fittings for use with
Thermo King truck unit applications.
NOTE: R-134a in disposable containers for automotive
applications is supplied in 30 pound and 50 pound
containers with Acme threads. See Warranty Bulletin 124
for specifics.
Leak Detection
Leaks can be detected by a Halogen leak detector such as
the G.E. H10G (TK No. 204-712) or portable leak detector
(TK No. 204-854). See Truck and Trailer Service Bulletin
T&T 048 for additional details.
Compressor Oil
As of January 1, 1993, Thermo King Corporation has
chosen to use a compressor oil called Polyol Ester (POE)—
also called ester based oil. POE oil is compatible with
R-134a and R-404A and can be used in low temperature
applications. This oil is available from service parts TK No.
203-413.