2 V-4000 Small Pneumatic Actuator for Small Control Brass Valves
Application Overview
The V-4000-1 is designed for use with Johnson
Controls small brass valves—normally open,
normally closed, and three-way mixing valve
styles.
The Small Pneumatic Actuator (V-4000-1) is
designed with a snap-on, hand tightened
mounting that uses no set screws and requires
no tools. It is designed to field replace oval-top
and other actuators installed on V-3854, V-3800,
and other valves.
Operating Principles
Air pressure from a pneumatic controller is
applied to the diaphragm of the actuator, which
moves a piston against the valve stem. The
piston will move the valve stem and plug until the
diaphragm pressure balances the valve return
spring force and the fluid forces. These fluid
forces will cause the operating range to shift
from the nominal spring range. Reducing the air
pressure to the diaphragm of the actuator allows
the spring to return the valve plug to its normal
position.
This actuator is based on a rolling diaphragm
design. The rolling diaphragm provides a
constant effective area throughout the valve
stem stroke. The actuator housing is
constructed of sturdy, glass-reinforced nylon.
Due to the simplicity of the design, it is more
economical to replace the actuator than to repair
it. Therefore, no repair parts are needed or
provided.
Installation Instructions
Assembling the actuator. No tools are
required for this operation.
1. Before mounting the actuator to the valve,
locate the retaining nut in the full up position,
completely disengaged from the yoke
threads (Figure 5).
Note: The actuator cannot be mounted or
removed if the retaining nut is located on
the yoke threads.
2. The actuator can be mounted on cage trim
or VT valves:
If the actuator is to be assembled to a
VT valve, insure that the plastic spring
seat retainer is in place (Figure 5). Use
the retainer furnished with the actuator if
there is no retainer in the valve. Insert
the retainer so that the projection at the
bottom of the retainer snaps into the
keyway at the bottom of the spring seat.
When properly inserted, the top of the
retainer will be below the top of the
spring seat.
If the actuator is being mounted on a
cage trim valve, check the spring gauge
height before mounting the actuator.
This measurement cannot exceed
1-13/16 inches (46 mm) as shown in
Figure 5. If the gauge height is greater
than 1-13/16 inches (46 mm), adjust it to
this value.
3. Tilt the actuator and slide it over the valve
spring as shown in Figure 2.
4. Tilt the actuator slightly, and snap the yoke
over the valve bonnet as shown in Figures 3
and 4.
5. Rotate top of actuator so that the air fitting is
in the desired position.
6. Secure the actuator to the valve by turning
the retaining nut onto the yoke threads.
While holding the actuator in position, turn
down the nut until it no longer turns freely.
Then tighten by hand one additional turn.
!
CAUTION: Hand tighten nut only —
do not use tools.
