Honeywell VRN Series Manual

VRN Pressure Independent Control
Valves and Actuators
Application
The VRN2 two-way pressure independent control valves
maintain constant flow of hot or chilled water with glycol
solutions up to 50% in closed-loop heating, ventilating,
and air conditioning (HVAC Division 23) systems
regardless of head pressure fluctuations above the
minimum specified pressure drop. These valve assemblies
can be used with Honeywell non-spring return or spring
return direct coupled actuators (DCA).
The built-in differential pressure regulator makes fluid
flow through the valve independent of changes in supply
pressure, eliminating "hunting" by the control system,
even at low coil flow. The pressure regulator virtually
eliminates cavitation in the valve, and decouples the
control valve from the effects of piping components such
as reducers and elbows.
Pressure independent control valves are sized to match
design coil flow regardless of coil size. VRN2 valves
eliminate the need to balance the system for proper flow,
and allow chillers to be operated at design temperature
differential for maximum efficiency at every load
condition. When used in a system with variable speed
pump drives, 3-way valves and coil bypass lines are not
Global Field Devices
required. In new construction, VRN2 valves perform better
than reverse return piping designs without the extra
materials these systems need.
Pressure-independent control requires less flow, enabling
use of smaller piping, pumps, and chillers.
Features
• Sizes from 1/2 to 3 in. with internal (female) NPT
connections.
• Controls hot or chilled water with up to 50% glycol.
• Regulated flow rates available from 1 to 95 gpm.
• Differential pressure regulator for constant pressure
drop across valve seat.
• Positive pressure, rolling diaphragm regulator design
for flow control accuracy of ±5%.
• Equal percentage flow characteristic using patented
flow control ball insert.
• Multiple maximum flow rates available per valve size.
• Patented ball seals for low operating torque.
• Nickel-chrome plated brass or stainless steel trim.
• Choice of factory-installed actuation using
Honeywell MVN or MN/MS series direct coupled
actuators: Floating, Modulating (2-10 V), Non-Spring
Return and Spring Return.
• Spring return actuators field-configurable for
normally open or normally closed fail-safe position.
• Removable, manual operating handle to control
valve during installation or in an event of power
failure.
• Upstream Test Port for venting or pressure gauge
attachment.
• Three actuator orientations on the valve for cramped
spaces.
• Integral snubber eliminates effect of system
pressure fluctuations and entrapped air while
improving flow performance.

Application .....................................................................................

Features ..........................................................................................

Specifications ...............................................................................
Ordering Information ................................................................
Typical Specifications ............................................................... 12
Installation .................................................................................... 13
Operation And Checkout .......................................................... 18

PRODUCT DATA

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38-00032-01