INSTALLATION
GA Industries silent check valves must be
correctly installed for proper operation. The flow
arrow or nameplate on the valve body must
point to the direction of forward flow. The valve
can be installed in a horizontal pipe or in a flow
up vertical pipe. The valve should be installed
with at least 3 diameters of upstream straight
pipe to minimize turbulent flow through the valve
which can contribute to vibration and premature
wear.
The valve should be installed between standard
ANSI B16.1 flat faced flanges. The inside
diameter of the inlet side mating flange must be
larger than the valve seat for proper seat
retention.
In some size GA Industries silent check valves,
there are two screws retaining the seat, but this
is only for transportation. When installed, the
seat must be retained by the inlet side mating
flange.
If the mating inlet flange has an expanded inside
diameter (such as cement lined pipe or slip-on
pipe flange) a support ring must be installed
between the pipe flange and the valve.
CAUTION
Valve and system damage may occur if mating
inlet flange does not overlap valve seat.
Full face flange gaskets are recommended, and
the inlet side gasket
’s inside diameter must
overlap the bronze or stainless-steel body seat
to provide a seal between the body and seat.
When wafer style valves are installed between
Class 125, the flange bolts/studs are in the
grooves on the outside of the body. When sizes
2-inch to 6-inch are installed between Class 250
flanges, the flange bolts/studs are outside the
grooves.
If ring gaskets are used the bolt material shall be
ASTM A307 Grade B (or equivalent). Higher
strength bolting should only be used with full-
face gaskets.
Lower heavy valves using slings or chains
around the valve body and/or the lifting eye.
Lubricate the bolts or studs and insert around
flange. Lightly tighten bolts until gaps are
eliminated. Torque bolts in an alternating
pattern in graduated steps. If leakage occurs
wait 24 hours and re-torque the bolts but do not
compress the gasket more than 50% or exceed
bolt maximum torque rating.
If installed outdoors, below ground in a vault or
in an unheated area, adequate freeze protection
must be provided.
An isolating valve should be installed between
the valve and the pipeline or system to facilitate
maintenance. 10-inch and smaller Figure 280-
D or 280-U globe style silent check valves have
enough clearance to allow most butterfly valves
to be directly bolted to its outlet. Refer to Table 1
for clearance dimensions. However, the plug
shaft in 12-inch size valves extends past the
outlet flange and may interfere with an adjacent
valve
’s operation.
PREVENTIVE MAINTENANCE
GA Industries silent check valves require no
scheduled lubrication, adjustment or preventive
maintenance.
A periodic inspection should be performed to
listen for leakage when the pump is shut down
and the valve is closed. If leakage is evident,
isolate the valve, remove it from the pipeline and
inspect seating surfaces for wear or damage.
TROUBLESHOOTING
•
Valve Chatters or Vibrates
Verify the flow velocity through the valve
is at least the 4 ft/sec necessary to
compress and stabilize the spring.
Turbulent flow through the valve can
cause instability, verify at least 3
diameters of straight pipe upstream of the
valve.
Cavitation sounds like rocks are passing
through the valve and results from
extremely high flowing velocity
•
Valve Leakage
Verify the inside diameter of the inlet
flange gasket overlaps the seat and body
Verify the seat is flush with the flange
face. If the seat has lifted above the
flange face mating flange and gasket are
not properly retaining the seat.
