Teledyne 4700 Serivce Manual page 74

4700 Refrigerated Sampler Service Guide
Section 3 Refrigeration System
3-14
2. Through the high pressure service port, pressurize the sys-
tem with dry nitrogen before charging to ensure that there
are no leaks. If there is a leak in the refrigeration system,
replacement is recommended. See the procedure in Section
3.4.4 for details about system replacement. See the proce-
dure in Section 3.4.1 for system repair information.
3. Through the high pressure service port, charge with
3.95 ± .17 oz. of refrigerant HFC-R134a.
The correct amount of refrigerant is critical to proper operation
of the 4700.
4. When charging is complete, crimp the high pressure ser-
vice port near the joint, and the extension close to the tee
(see Figure 3-16-A).
5. Braze the ends of the service port tubes with silver solder
to seal.
All exposed copper tubing MUST be coated with acrylic paint
and then covered with shrink tubing to prevent corrosion.
6. Slide the 3" shrink tubing, see Figure 3-16-A) over the
joints and shrink-seal to protect the metal. All bare metal
must be covered.
7. Apply 15" of cork insulating tape to the suction line, begin-
ning at the compressor and ending even with the bottom of
the metal tab on the frame (see Figure 3-16-B).
CAUTION
CAUTION