User Guide

ManualsBrandsBarber Colman ManualsHVAC Replacement Parts5/8" O.D. Flare Three-Mixing Valve (2.2 cv)

Application

VB-7312 series three-way mixing valves control hot or

chilled water from 20 to 281°F (-7 to 138°C) in heating

or air conditioning systems. These valves must be

piped with two inlets (“A” and “B” ports) and one outlet

(“AB” port). They are used for two-position or

proportional control applications. Valve assemblies

require an actuator and a valve linkage that must be

purchased separately.

Danger:

Do not use for combustible gas applications.

The VB-7312 series valve packings are not rated for

combustible gas applications, and if used in these

applications, gas leaks and explosions could result.

Features

• 250 psig pressure rating per ANSI Standards

(B16.15–1985) for cast bronze bodies

• Spring-loaded TFE packing

• 5/8" O.D., 45° SAE flared end fittings

Applicable Literature

• TAC Valve Products Catalog, F-27384

• TAC Cross-Reference Guide, F-23638

• TAC Reference Manual, F-21683

• TAC Application Manual, F-21335

• Control Valve Sizing, F-13755

• Valve Selection Chart for Water, F-11080

• EN-205 Water System Guidelines, F-26080

VB-7312 Series

5/8" O.D., 45° SAE Flared

Three-Way Mixing Valves

General Instructions

Summary of content (8 pages)

PAGE 1
VB-7312 Series 5/8" O.D., 45° SAE Flared Three-Way Mixing Valves General Instructions Application VB-7312 series three-way mixing valves control hot or chilled water from 20 to 281°F (-7 to 138°C) in heating or air conditioning systems. These valves must be piped with two inlets (“A” and “B” ports) and one outlet (“AB” port). They are used for two-position or proportional control applications. Valve assemblies require an actuator and a valve linkage that must be purchased separately.
PAGE 2
SPECIFICATIONS Table-1 Specifications/Models. Valve Body Series VB-7312-0-4-P Specifications Service Chilled or Hot Water Flow Characteristics (Figure-1) Mixing Size 5/8" O.D.
PAGE 3
Flow Characteristics Three-way mixing valves are designed so that the flow from either of the inlet ports to the outlet is approximately linear, which means the total flow from the outlet is almost constant over the stroke of the valve stem. See Figure-1 for typical characteristic of VB-7312 series valve bodies. 100% 90% 80% Rated Flow 70% 60% 50% 40% 30% "A" Port 20% "B" Port 10% Stem In 100% 80% 60% 40% 20% 0% 0% Stem Out Stroke Figure-1 Typical Flow Characteristics.
PAGE 4
VALVE SIZING AND SELECTION Water Two-position Two-position control valves are normally selected “line size” to keep pressure drop at a minimum. If it is desirable to reduce the valve below line size, then 10% of “available pressure” (that is, the pump pressure differential available between supply and return mains with design flow at the valve location) is normally used to select the valve.
PAGE 5
Cavitation Limitations on Valve Pressure Drop A valve selected with too high a pressure drop can cause erosion of discs and/or wire drawing of the seat. In addition, cavitation can cause noise, damage to the valve trim (and possibly the body), and choke the flow through the valve. Do not exceed the maximum differential pressure (pressure drop) for the valve selected.
PAGE 6
INSTALLATION Inspection Requirements Inspect the package for damage. If damaged, notify the appropriate carrier immediately. If undamaged, open the package and inspect the device for obvious damage. Return damaged products. • Training: Installer must be a qualified, experienced technician • Appropriate accessories Caution: • Install the valve with the flow in the direction of the flow arrows (“A” and “B” ports are the inlets and “AB” port is the outlet). • Do not exceed the ratings of the device.
PAGE 7
Valve A B System Pump A B Supply Bypass Boiler Return Figure-4 Typical Boiler Piping When Used in a Hot Water Reset Application. Coil Balancing Cock Secondary Pump Valve A From Other Zones B Return A B To Other Zones Balancing Cock Supply Figure-5 Typical Primary-Secondary Piping. CHECKOUT 1. Make sure the valve stem operates smoothly before installing the valve linkage and the actuator. 2.
PAGE 8
Durability of valve stems and packings is dependent on maintaining non-damaging water conditions. Inadequate water treatment or filtration, not in accordance with chemical supplier/ASHRAE handbook recommendations, can result in corrosion, scale, and abrasive particle formation. Scale and particulates can result in stem and packing scratches and can adversely affect packing life and other parts of the hydronic system.