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Table Of Contents

WARNING

Powers

Controls

Technical Instructions

Document No. 155-092P25

VP 658-4

November 20, 2008

VP 658 S and VP 658 SC Powertop

Sequence and Sequence

Changeover Valves

Siemens Industry, Inc.

Description

The VP 658 S sequence and VP 658 SC sequence changeover valves are designed to

select and modulate the flow of either hot or chilled water without mixing for radiant panel

and similar four-pipe single coil/panel applications. The sequence valve has two inlets

and one outlet whereas the changeover valve has one inlet and two outlets.

Features

• Stainless steel stem for smooth operation and durability

• Large diaphragm area for control accuracy arid tight close off

• Removable actuator for ease of servicing

• Durable actuator made to eliminate electrolytic action

• Replaceable disc assemblies

• Matched sequencing of control and changeover valves

Product Numbers

Table 1.

Product Number

Valve Type

Valve Size

658-0050 1.5 Sequence 1/2”

658-0051 2.5 Sequence 1/2”

658-0052 2.5 Changeover 1/2“

Warning/Caution Notations

WARNING

Personal injury/loss of life may occur if

you not perform a procedure as

specified.

CAUTION

Equipment damage, or loss of data

may occur if you do not perform a

procedure as specified.

Summary of content (10 pages)

PAGE 1
Technical Instructions Document No. 155-092P25 VP 658-4 November 20, 2008 PowersTM Controls VP 658 S and VP 658 SC Powertop Sequence and Sequence Changeover Valves Description Features The VP 658 S sequence and VP 658 SC sequence changeover valves are designed to select and modulate the flow of either hot or chilled water without mixing for radiant panel and similar four-pipe single coil/panel applications.
PAGE 2
Technical Instructions Document No. 155-092P25 November 20, 2008 Valve stroke See Tables 1 and 2. 1/2” SAE Flared 2 inlets, 1 outlet 1 inlet, 2 outlets Normally Open (NO) Hot to common Normally Closed (NC) Cold to common 13/32-inch (10 mm) Material Body Seat Stem Stem packing (O-rings) Shut-off disc Throttle plug Bronze Bronze Stainless steel EP rubber Buna-N Brass Valve Actuator Nominal spring range Diaphragm Effective area Material Max. air pressure See Figure 1.
PAGE 3
VP 658 S and VP 658 SC Powertop Sequence and Sequence Changeover Valves Technical Instructions Document No. 155-092P25 November 20, 2008 Table 2. Water Capacity - U.S. Gallons Per Minute. Pressure Differential psi Valve Size and Type CV 1 2 4 6 8 10 15 20 25 1/2" Sequence 1.5 2.1 3 3.7 4.2 4.7 5.8 6.7 7.5 1/2" Sequence 2.5 3.5 5 6.1 7.1 7.9 9.7 11.2 12.5 1/2" Changeover 2.5 - - - - - - - - Table 3. Body Rating.
PAGE 4
Technical Instructions Document No. 155-092P25 November 20, 2008 Operation The sequence valve, (Figure 3), is piped to the inlet of a coil. Therefore, it has hot water supply and chilled water supply connected to it. The changeover valve, (Figure 4), is piped to the outlet of the coil. Therefore, it has the hot water and chilled water returns connected to it. For the sequence valve, water should flow into the hot and cold ports and out of the common.
PAGE 5
VP 658 S and VP 658 SC Powertop Sequence and Sequence Changeover Valves Sizing Technical Instructions Document No. 155-092P25 November 20, 2008 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 may initiate cycling and the seat and disc may be damaged because of the restricted opening. Correct sizing of the control valve for actual expected conditions is considered essential for good control.
PAGE 6
Technical Instructions Document No. 155-092P25 November 20, 2008 Table 4. Part Numbers (See Figure 5). Part Number Item Description Qty CV = 1.5 CV = 2.5 CV = 2.5 seq. seq. c.o. Material 1 Actuator Housing - Upper 1 See Item 26 Assembly. Nylon 2 Thread Forming Screw 8 Steel 3 Diaphragm 1 See Item 27 Kit or Item 26 Assembly.
PAGE 7
VP 658 S and VP 658 SC Powertop Sequence and Sequence Changeover Valves Technical Instructions Document No. 155-092P25 November 20, 2008 Valve Components Detail of Stem Packing. Figure 5. Valve Construction (See Table 4). Service WARNING: Before doing any service work, shut off the medium (water, etc.) to the valve and remove and cap the airline to the valve actuator to prevent personal injury and equipment damage.
PAGE 8
Technical Instructions Document No. 155-092P25 November 20, 2008 Actuator Assembly Replacement 1. Loosen the two lower housing screws that clamp it to the bonnet. 2. Using two open-end wrenches, loosen the stem locknuts. 3. Unscrew actuator assembly from stem and remove it, as shown in Figure 6. 4. Before installing new actuator assembly, push stem down. There must be at least 1/16-inch (2 mm) clearance between lower stem locknut and cap. 5. Pull stem up and install actuator assembly. 6.
PAGE 9
VP 658 S and VP 658 SC Powertop Sequence and Sequence Changeover Valves Technical Instructions Document No. 155-092P25 November 20, 2008 Valve Disc Replacement, continued Figure 7. Valve Body Assembly. Siemens Industry, Inc.
PAGE 10
Technical Instructions Document No. 155-092P25 November 20, 2008 Dimensions Figure 8. Dimensions. 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. © 2008 Siemens Industry, Inc. Siemens Industry, Inc.