Q33. If an oil separator is used at the bottom of a discharge riser on multiple compressor applications, the need for a double riser is eliminated. True/False.

MAINTENANCE, SERVICE, AND REPAIR OF REFRIGERATION EQUIPMENT

Learning Objective: Understand different types of maintenance equipment and methods for basic maintenance, service, and repair of refrigeration systems and components.

As a Utilitiesman, you must be able to maintain, service, and repair refrigeration equipment. This phase of our discussion provides information on different jobs that you may be assigned. When information here varies from that in the latest federal or military specifications, the specifications apply. You will find the "Troubleshooting Checklist - Refrigeration Systems," which is presented in table V, appendix II, at the end of this book, helpful in locating and correcting troubles. It is not intended to be all encompassing. Manufacturers also provide instruction manuals to aid you in maintaining and servicing their equipment.

SERVICING EQUIPMENT

Repair and service work on a refrigeration system consists mainly of containing refrigerant and measuring pressures accurately. One piece of equipment is the refrigerant gauge manifold set (fig. 6-48). It consists of a 0-500 psig gauge for measuring pressure at the compressor high side, a compound gauge (0-250 psig and 0 to -30 inches of mercury) to measure the low or suction side, and valves to control admission of the refrigerant to the refrigeration system. It also has the connections and lines required to connect the test set to the system. Depending on test and service requirements, the gauge set can be connected to the low side, the high side, a source of vacuum, or a refrigerant cylinder. A swiveling hanger allows the test set to be hung easily, and the three additional blank connections allow for securing the open ends of the three lines when the gauge set is not in use. There is always a path from the low-side and high-side input to the low-side and high-side gauge (fig. 6-49).

Another important piece of equipment is the portable vacuum pump. The type listed in the Seabee

Figure 6-48. - Refrigerant gauge manifold set.

Figure 6-49. - Internal view of a refrigerant gauge manifold set.

Table of Allowance is a sealed unit consisting of a single-piston vacuum pump driven by an electric motor. A vacuum pump is the same as a compressor, except the valves are arranged so the suction valve is opened only when the suction developed by the downward stroke of the piston is greater than the vacuum already in the line. This vacuum pump can develop a vacuum close to -30 inches of mercury, which can be read on the gauge mounted on the unit