ANSI ASHRAE-158.1-2004 pdf download Methods of Testing Capacity of Refrigerant Solenoid Valves
4. INSTRUMENTATION 4.1 General. Instruments shall have the accuracies listed in this standard and shall be certified standard instruments.
4.2 Temperature-Measuring Instruments 4.2.1 Temperature shall be measured with any device meeting the requirements of ANSI/ASHRAE Standard 41.1- 1986 (RA 2001), Standard Method of Temperature Measurement.
4 4.2.2 The accuracy of temperature-measuring instruments shall be within ±0.28°C (0.5°F).
4.3 Pressure-Measuring Instruments
4.3.1 Pressure shall be measured with any device meeting the requirements of ANSI/ASHRAE Standard 41.3-1989R, Standard Method for Pressure Measurement. 5
4.3.2 The accuracy of pressure-measuring instruments shall be within ±1.0% of the pressure reading. 4
.4 Fluid Flow-Measuring Instruments 6
4.4.1 The accuracy of flow-measuring instruments shall be within ±2.0% of the indicated value.
4.4.2 In no case shall the smallest scale division of the measuring instrument exceed 2 1 / 2 times the specified accuracy.
5. GENERAL PIPING SPECIFICATIONS
5.1 Main Size. The pipe or tubing used for the inlet and outlet connecting mains to the solenoid valve being tested shall be the size and type accommodated by the solenoid valve body connections. The main shall be free from scale, rust, or other obstructions that may cause excessive turbulence.
.2 Main Length. The inlet and outlet mains connected to the solenoid valve being tested shall be straight for a mini- mum of 14 internal diameters from the face of the solenoid valve inlet and outlet connections, respectively.
5.3 Pressure-Tap Holes. Pressure tap holes must be located at the appropriate points on the circumference of the main with respect to the adjacent surroundings. With horizontal mains, pressure-tap hole position depends largely on the fluid flowing. With liquids, the pressure-tap holes shall be level with or below the centerline of the main. Pressure-tap holes should not be positioned on the bottom of the main due to possible blockage of the hole by foreign matter. The inner surface of the main adjoining holes shall be free of imperfections, such as rivet heads, jogs, or other sources of eddies, to ensure parallel flow. All pressure-tap holes should be located at the same elevation and on the same side of the main. The internal diameter shall be straight and of uniform size for not less than two diameters. The inner rim of the hole shall be flush with the inner surface of the main and be free of any burrs, exces- sive chamfers, or jagged edges.