VP531A,C PNEUMATIC TERMINAL UNIT VALVES
FLOW
C7988
AIR CONNECTION FOR 1/4 IN. O.D. (6mm) PLASTIC TUBING
COVER FASTENER
BONNET NUT
INLET TUBE 5/8 OR 7/8 IN. O.D.
(6 OR 22 mm) COPPER TUBE
ADAPTER (OBTAIN
LOCALLY IF NEEDED)
TERMINAL UNIT
SUPPLY
COPPER CONNECTION 5/8 OR 7/8 IN. O.D. (16 OR 22mm)
Fig. 2. VP531A,C solder body connection.
When connecting the valve into the system, use pipe dope
VP531A,C NPT Threaded Valve
sparingly and apply to the pipe threads only.
It may be convenient to remove the top and insert assembly
when installing the valve. If so, unscrew the bonnet nut and lift
IMPORTANT
the assembly out. When installation is complete, replace the
Do not allow pipe dope or other foreign material to
top and insert assembly and tighten the bonnet nut firmly
enter the piping where it could lodge under the valve
enough to compress the copper washer seal (35 to 45 ft-lb
seat and prevent proper closing of the valve.
torque).
Use proper piping methods, when installing the valve to
prevent distortion of the valve body. See Fig. 3.
EXCESS DOPE
PIPE SIZE
EFFECTIVE LENGTH
OF THREADS
1/2 in.
1/2 in. (13 mm)
3/4 in.
9/16 in. (14 mm)
2 THREADS CLEAN –
MAY BLOCK DISC
MODERATE
OFF VALVE SEAT
AMOUNT OF DOPE
LOOSE CHIPS
WRONG
– TOO
RIGHT
– FULL
MANY THREADS
THREAD (SEE TABLE)
WRONG
RIGHT
VISE GRIPS HEX END NEXT TO PIPE
M16447
VISE MAY SQUEEZE VALVE SEAT OUT OF
ROUND. IF VISE IS USED, GRIP ONLY THE
HEX NEXT TO PIPE BEING INSERTED.
VISE HOLDS PIPE
SECURELY
AGAINST TURNING
PARALLEL-JAW
WRENCH GRIPS HEX
OR FLATS NEXT TO PIPE
Fig. 3. Proper threaded valve installation practice.
Typical Operation
VP531
C7992
SYSTEM
SUPPLY
AIR
PRESSURE
CONTROL
An increase in control air pressure to the valve acts to move
the valve stem downward, toward the closed position,
modulating flow through the valve.
Fig. 4. Typical operation.
95-7251EF–1
2