Thermo King 098203, Maintenance Manual

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Refrigeration Maintenance
174
Gauge Manifold Set Installation & Removal
Thermo King recommends the use of access valves or self-sealing, quick disconnect fittings. This limits
the loss of refrigerant into the atmosphere. A separate gauge manifold set with low loss fittings (refer to
Tool Catalog) should be dedicated for use with R-404A only. Gauge hoses should also be dedicated to
R-404A.
NOTE: Carefully check to ensure that access connections are functioning properly when any of these
devices are used.
Gauge Manifold Set Installation
The following procedure purges the gauge hoses.The procedure must be followed when using new gauges
or hoses for the first time. The system should be operating on Cool (10 psig [69 kPa] or greater suction
pressure) when using this procedure to purge the low side hose. Gauge hoses may be removed and
re-installed without additional purging so long as a slight positive pressure remains in the manifold and
lines.
1. Inspect gauge manifold for proper hose and fitting connections.
2. Clean dirt and moisture from around service ports.
3. Remove small service port caps from suction and discharge service fittings. Save and reuse the caps
and sealing washers or gaskets.
4. Rotate both hose coupler hand wheels counterclockwise to back the stem out of the high and low hose
fittings. Attach low hose (compound gauge) to the suction line valve port.
5. Open the suction service manifold hand valve fully with 69 kPa, 0.69 bar, 10 psig or greater pressure
in the low side (unit operating on Cool). Rotate the suction hose fitting hand wheel clockwise to open
(depress) the suction line port valve to the low hose.
6. Slowly screw a 1/2 inch ACME fitting into the low loss fitting on the manifold’s service (center) line
to purge the suction and service hoses. Remove ACME fitting after purging.
7. Close the suction service manifold hand valve fully to center port.
8. Attach high side hose (pressure gauge) to the discharge service line port.
9. Open discharge service manifold hand valve fully. Rotate discharge fitting hand wheel clockwise to
open (depress) discharge line port valve to the high hose.
10. Slowly screw a 1/2 inch ACME fitting into the manifold’s service (center) line to purge the high and
service hoses. Remove ACME fitting after purging.
11. Close discharge service manifold hand valve fully to center port. You are now ready to use the gauge
manifold to check system pressures or perform most service procedures.
NOTE: These gauges may be removed and reinstalled without additional purging so long as a
slight positive pressure remains in the manifold and hoses when removed from the unit.