Siemens Industry, Inc. Powers™ Controls Technical Instructions Document No. 155-311P25 VP 656-5 March 7, 2005 Powermite Two-Way Flared Valves Normally Open/Normally Closed Description The VP 656 normally open and normally closed flared valves are pneumatically operated valves designed to control the flow of both water and steam. Features • Enclosed actuator housing to protect the diaphragm, spring, etc. • Small size allows installation in restricted space • Replaceable soft disc provides tight shut-off actuator can be rotated to facilitate air connection • Stainless steel valve stem to reduce friction and corrosion Application The VP 656 flared valves are recommended for control of hot or chilled water and steam for convectors, fan coil units, radiation, reheat coils and similar terminal unit applications. The dual seating packed construction allow its use in systems having relatively high pressures. Typical uses are sites where efficient economical control is desired. The small overall size lends itself to installation within a cabinet enclosure where available space is limited. Product Numbers Table 1. Action Valve Size Cv (Kvs) Product Number Normally Open 1/2-inch (15 mm) 0.9 (0.77) 656-0004 1/2-inch (15 mm) 2.1 (1.8) 656-0002 Normally Closed 1/2-inch (15 mm) 2.1 (1.8) 656-0012 Specifications Line size 1/2-inch (15 mm) Capacity See Tables 2 through 5. Body style Globe-flared Action Normally Closed (NC) Normally Open (NO) Technical Instructions Powermite Two-Way Flared Valves Normally Open/Normally Closed Document No. 155-311P25 March 7, 2005 Page 2 Siemens Industry, Inc. Specifications, Con’t Stem travel 1/4-inch (6.3 mm) Valve body rating ANSI 250. See Table 6. Material Body and seat Bronze Stem Stainless steel Packing EP rubber quad ring Operating Controlled medium Water, steam, ethylene glycol solution Maximum medium temperature 250°F (121°C) Maximum medium inlet pressure Water See Table 6. Steam 15 psig (103 kPa) Maximum recommended differential pressure for modulating service Water 20 psig (138 kPa) Steam 15 psig (103 kPa) Close-off Normally Closed See Figure 1. Normally Open See Figure 1. Flow characteristic Modified equal percentage Actuator Nominal spring range NC 10 to 15 psi (69 to 103 kPa) NO 3 to 8 psi (21 to 55 kPa) Diaphragm Effective area 3.4 inch 2 (22 cm 2 ) Ambient temperature range 30 to 160°F (-1 to 71°C) Maximum air supply to the diaphragm 30 psig (207 kPa) Material Silicone rubber Miscellaneous Dimensions See Figures 2 and 3. Weight 2.2 lb (1kg) Service Kits Diaphragm replacement kit (package of 5) 656-736 Repack kit (for 6 valves) 656-601 Rebuild/repack kit NO 656-761 NC models 2 and 3 656-014 NC discontinued model 1 656-763 Shut off disc kit (package of 10) NO 656-740 NC 656-800 Replacement top NO only Cv 0.9 656-830 Cv 2.1 656-599 Powermite Two-Way Flared Valves Normally Open/Normally Closed Technical Instructions 155-311P25 March 7, 2005 Siemens Industry, Inc. Page 3 Table 2. Maximum Water Capacity - U.S. Gallons per Minute. Valve Size Pressure Differential - psi in inches Cv\1 2 3 4 5 6 8 10 12 14 15 16 17 18 19 20 1/2 0.9 1.3 1.6 1.78 2 2.2 2.5 2.8 3.1 3.4 3.5 3.6 3.7 3.8 3.9 4.0 2.1 3 3.6 4.2 4.7 5.1 5.9 6.6 7.3 7.9 8.1 8.4 8.7 8.9 9.2 9.4 Table 3. Maximum Water Capacity - Cubic Meters per Hour (m3/h). Valve Size Pressure Differential - kPa in mm 1 10 20 30 40 50 60 80 Kvs/ 100 150 200 300 400 500 15 0.08 0.24 0.34 0.42 0.49 0.54 0.60 0.69 0.77 0.94 1.09 1.33 2.56 5.86 0.18 0.57 0.80 0.98 1.13 1.27 1.39 1.60 1.80 2.19 2.53 3.10 3.58 4.0 Table 4. Maximum Steam Capacity - Pounds per Hour. Valve Inlet Pressure - psig Size 2 5 10 15 in Pressure Differential - psi inches 1 2 1 2 3 4 5 2 4 6 8 10 6 9 12 15 1/2 (Cv 0.9) 11 15 12 16 20 22 25 18 25 30 34 37 25 40 45 49 1/2 (Cv 2.1) 25 35 27 38 46 52 58 43 59 71 80 87 57 94 105 113 Table 5. Steam Capacity - Kilograms per Hour. Valve Inlet Pressure - kPa Size 50 100 in Pressure Differential – kPa mm 10 25 10 20 50 15 (Kvs 0.77) 4.3 6.7 5.4 7.7 12.1 15 (Kvs 1.80) 9 14 13 18 28 Table 6. Body Temperature-Pressure Rating. Valve Body Temperature Pressure psig (kPa) °F °C ANSI Class 250 Bronze -20 to +150 +200 +250 (-30 to 66) (93) (121) 400 (2758) 385 (2655) 365 (2586) Technical Instructions Powermite Two-Way Flared Valves Normally Open/Normally Closed Document No. 155-311P25 March 7, 2005 Page 4 Siemens Industry, Inc. Normally Open Normally Closed Figure 1. Nominal Close-off Ratings. Operation The actuator spring provides the necessary force to hold the stem in the raised or normal position. An increase in control pressure overcomes the spring pressure and moves the stem downward. In a normally closed valve, this increases the flow of fluid through the valve. In a normally open valve, an increase in pressure decreases the flow of fluid though the valve. With the loss of control pressure, the spring returns the valve to its normal position. Sizing The sizing of a valve is important for correct system operation. An undersized valve will not have sufficient capacity at maximum load. An oversized valve can initiate cycling, and the seat and throttling plug can be damaged because of the restricted opening. Correct sizing of the control valve for actual expected conditions is essential for good control. Some variables that must be determined are: • The medium to be controlled: water, etc. • The maximum inlet temperature and pressure of the medium at the valve. • The pressure differential that will exist across the valve under maximum load demand. • The maximum capacity the valve must deliver. • The maximum line pressure differential the valve actuator must close against. • See Application Bulletin (AB)-1 Control Valve Selection and Sizing (155-285) for further recommendations. See Tables 2 through 5 for valve capacities. Powermite Two-Way Flared Valves Normally Open/Normally Closed Technical Instructions 155-311P25 March 7, 2005 Siemens Industry, Inc. Page 5 Installation In concealed installations, allow 2 inches (50 mm) from the top of the actuator to remove the upper housing for valve servicing. Install all valves so that the flow is directed under the valve seat. Flow direction arrows are cast on the valve body. Never use the valve housing as a lever arm to tighten the body when taking up on a thread. The preferred installation position is upright. Install the valve in any position except upside down. Rotate the valve top to allow piping the control air from a convenient position. Install hand valves on the supply and return piping to allow for servicing. Dimensions Figure 2. Normally Open. Figure 3. Normally Closed. Table 7. Troubleshooting. Complaint Problem Recommended Correction Complaint Problem Recommended Correction Valve Noise Excessive fluid velocity in piping or excessive pressure drop Reduce pressure drop or change valve size Inadequate Close-off Insufficient control air pressure Raise control air pressure Improper direction flow Re-pipe valve for flow as stamped on valve body Excessive pressure drop across valve Reduce system differential or in- crease control air pressure Flashing because of low system pres- sure or excessive fluid temperature Basic system problem cannot be corrected within valve Foreign material in valve Flush system or clean out foreign matter Fluid leaks Damaged valve or worn packing Replace valve or packing Damaged or worn valve disc or diaphragm Replace disc or diaphragm Technical Instructions Powermite Two-Way Flared Valves Normally Open/Normally Closed Document No. 155-311P25 March 7, 2005 Page 6 Siemens Industry, Inc. Table 8. Valve Assembly Parts and Service Kits. See Figures 4 and 5. Normally Open Normally Closed Item Description Kit Item Number Cv 0.9 Cv 2.1 Kit Item Number Q’ty Material 1 E-ring Items 29 and 31 Kits 1 Phos. Bronze 2 Washer Item 31 Kit 1 Brass 3 Spring — — — 1 Steel 4 Housing screw Items 28 and 31 Kits 4 Steel 5 Lower housing — — — 1 Aluminum 6 Valve stem Item 31 Kit 1 Stainless Steel 7 Upper quad ring retainer Items 29 and 31 Kits 1 Brass 8 Large retaining ring Items 29 and 31 Kits 1 Steel 9 Retaining ring Items 29 and 31 Kits 1 Stainless Steel 10 Bonnet — — — 1 Brass 11 Stem bearing — — — 1 Oilite 12 Disc holder Item 31 Kit 1 Brass 13 Shut-off disc Items 30 and 31 Kits 1 EP Rubber 14 Throttling nut Item 31 Kit 1 Brass 15 Washer NC only — — Item 31 Kit 1 Brass 16 Retaining nut NC only — — Item 31 Kit 1 Brass 17 Upper housing — — — 1 Aluminum 18 Piston plate — — — 1 Brass 19 Diaphragm Item 28 Kit 1 Silicone Rubber 20 Piston cup — — — 1 Brass 21 Stem packing quad ring — — Item 31 Kit 2 EP 22 Lower quad ring retainer — — — 1 Brass 23 Spring — — — 1 Phos Bronze 24 Valve body and seat — — — 1 Bronze 25 O-ring NO Items 30 and 31 Kits — 1 EP Rubber O-ring NC — — Items 30 and 31 Kits 2 26 Valve Cap NC only — — — 1 Brass 27 Washer NC only — — Item 31 Kit Plated steel 28 Diaphragm kit 656-736 656-736 — — 29 Repack kit 656-601 656-601 — — 30 Shut-off disc kit 656-740 657-800 — — 31 Rebuild/repack kit 656-761 656-014 — — — Replacement top 656-830 656-599 N/A — — Powermite Two-Way Flared Valves Normally Open/Normally Closed Technical Instructions 155-311P25 March 7, 2005 Information in this publication is based on current specifications. The company reserves the right to make changes in specifications and models as design improvements are introduced. Powers is a registered trademark of Siemens Industry, Inc. Product or company names mentioned herein may be the trademarks of their respective owners. © 2005 Siemens Industry, Inc. Siemens Industry, Inc. Building Technologies Division 1000 Deerfield Parkway Buffalo Grove, IL 60089 + 1 847-215-1000 Your feedback is important to us. If you have comments about this document, please send them to sbt_technical.editor.us.sbt@siemens.com Document No. 155-311P25 Printed in the USA Page 7 Parts of the Valve Assembly Figure 4. Normally Open. See Table 8. Figure 5. Normally Closed. See Table 8. Next >