Category Archives for Controlling Refrigerant

Discharge-Bypass Valves Installation

Bypass valves can be installed in horizontal or vertical lines, whichever best suits the application and permits easy accessibility to the valves. However, consideration should be given to locating these valves so that they do not act as oil traps. … Continue reading

17. January 2011 by admin
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Bypass to Evaporator Inlet without Distributor

On many applications, it may be necessary to bypass directly into the suction line. This is generally true of systems with multi evaporators or remote-condensing units. It may also be true for existing systems where it is easier to connect … Continue reading

17. January 2011 by admin
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Externally Equalized Bypass Valves

The primary function of the DBV is to maintain suction pressure. Thus, the compressor suction pressure is the control pressure. It must be exerted on the underside of the valve diaphragm. When the DBV is applied as shown in Fig. … Continue reading

17. January 2011 by admin
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Discharge-Bypass Valves Application

DBVs provide an economical method of compressor capacity control in place of cylinder unloaders or of handling unloading requirements below the last step of cylinder unloading. On air-conditioning systems, the minimum allowable evaporating temperature that will avoid coil icing depends … Continue reading

17. January 2011 by admin
Categories: Controlling Refrigerant | Tags: | 1 comment

Discharge-Bypass Valves Operation

Discharge-bypass valves (DBV) respond to changes in downstream or suction pressure (see Fig. 11-37). When the evaporating pressure is above the valve setting, the valve remains closed. As the suction pressure drops below the valve setting, the valve responds and … Continue reading

17. January 2011 by admin
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Discharge-Bypass Valves

On many air-conditioning and refrigeration systems it is desirable to limit the minimum evaporating pressure. This is so especially during periods of low load either to prevent coil icing or to avoid operating the compressor at lower suction pressure than … Continue reading

17. January 2011 by admin
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Nonadjustable ORO/ORD system operation

The nonadjustable ORO head pressure-control valve and the ORD pressure-differential valve offer the most economical system of refrigerant side head-pressure control. Just as the ORI/ORD system simplified this type of control, the ORO/ORD system offers the capability of locating the … Continue reading

17. January 2011 by admin
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Head-Pressure Control Valve Test and operating pressures

Excessive leak testing or operating pressures may damage these valves and reduce the life of the operating members. For leak detection, an inert dry gas such as nitrogen or carbon dioxide can be added to an idle system to supplement … Continue reading

17. January 2011 by admin
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Head-Pressure Control Valve Brazing procedures

Any of the commonly used brazing alloys for high-side usage are satisfactory. It is very important that the internal parts be protected by wrapping the valve with a wet cloth to keep the body temperature below 250°F (121°C). Also, when … Continue reading

17. January 2011 by admin
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ORD valve operation

The ORD valve is a pressure differential valve. It responds to changes in the pressure difference across the valve (see Fig. 11-34). The valve designation stands for opens on rise of differential pressure. Therefore, the ORD is dependent on some … Continue reading

17. January 2011 by admin
Categories: Controlling Refrigerant | Tags: | Leave a comment

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