Refrigeration Service Operations (Rev. 04/03)
81
Three-way Valve Assembly
R-134a and R-404A
The refrigeration industry has introduced two new refriger-
ants called R-134a and R-404A. Both refrigerations 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 haz-
ard 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. refriger-
ant capacities are slightly less than CFC refrigerants.
Unit Identification
Units charged with R-134a and 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 “RD-II 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 containers are available. When purchasing
R-134a in 30 pound or 50 pound containers, specify indus-
trial containers with 1/4 inch flare fittings to receiver con-
tainers with 1/4 inch flare fittings for use with Thermo King
truck unit applications.
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