Gauge Manifold Set Installation and 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/R-452A only. Gauge hoses should also be dedicated to R-404A/R-452A.

Note Carefully check to verify that access connections are functioning properly when any of these devices are used.

Parent topic: Refrigeration Maintenance

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.
Purging Gauge Manifold
      
  1 Suction Connection
  2 Discharge Connection
     
     
     
     
     

Removal

    Warning
  • Personal Protective Equipment (PPE) Required
  • Protect your eyes from contact with refrigerant oil. The oil can cause serious eye injuries. Protect skin and clothing from prolonged or repeated contact with refrigerant oil. To prevent irritation, wash your hands and clothing thoroughly after handling the oil. Rubber gloves are recommended. When working with or around hazardous chemicals, ALWAYS refer to the applicable Material Data Safety Sheets (MSDS) and OSHA/GHS (Global Harmonized System of Classification and Labelling of Chemicals) guidelines for information on allowable personal exposure levels, proper respiratory protection, and handling instructions.
Note THE SYSTEM SHOULD BE RUNNING to verify minimum refrigerant release to the atmosphere,. However, this is not possible in all cases, but the same procedure should be followed.

  1. Rotate discharge hose fitting hand wheel counterclockwise to withdraw the fitting stem from the discharge line port valve. Then open both service manifold valves to center port.

  2. Operate the unit on Cool using the “CAPACITY 100 percent” test from the Manual Function Test menu of the controller.

  3. Rotate the suction hose coupler hand wheel counterclockwise to withdraw the fitting stem from the suction line port valve. Then turn the unit off.

  4. Remove the gauge lines from the suction and discharge service fittings and cap the service ports.

  5. Secure all manifold lines to manifold hose anchors when the manifold is not in use.