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VALVE CONSTRUCTION
The standard Figure 250 Swing Check Valve has a
cast iron body, bronze or stainless steel (designated
by an "S" in the Figure Number) body seat, stainless
steel hinge shaft and cast iron disc with a rubber disc
An "M" suffixed to the Figure Number (e.g.,
seat.
250-DM, 250-USM) indicates optional metal-to-metal
seating was supplied. Refer to the List of Materials
submitted for the order if non-standard materials were
provided.
Refer to Page 5 for details of construction and parts
location.
START-UP
The valve generally does not require any calibration
or adjustment prior to start-up. The counterweight(s)
should be initially placed at the far end of the arm and
secured by tightening the set screw (31A).
The valve should smoothly swing open as flow
through the valve increases. The amount of opening
depends on the flow velocity through the valve and
can
be
observed
by
counterweight arm. The valve is "full ported" at about
25 degrees of swing but can swing open as much as
60 degrees.
Shut down the pump and observe the valve's closure.
If the valve was less than 60 degrees open and the
closure was smooth and quiet, then the weight(s) may
be moved incrementally toward the shaft.
these steps to the point where the valve opens to the
extent possible but still closes quietly.
The air-cushion chamber cannot retard the valve's
closure or prevent the valve from being slammed shut
due to the tremendous forces of the reversing water.
Non-slam
operation
is
counterweight closes the valve prior to flow reversal.
In extreme cases, it may be necessary to install
additional counterweight(s) to effect non-slam closure.
The cushion chamber will minimize the slam tendency
when the valve closes too quickly due to its own
counterweight action. An inward adjustment of the
adjusting sleeve (26) will increase this cushioning
effect.
PREVENTIVE MAINTENANCE
Figure 250 Swing Check Valves require no scheduled
lubrication, adjustment or preventive maintenance.
A monthly inspection should be performed for the first
6 months of operation to ensure the valve is
functioning properly and there is no external fluid
leakage or audible evidence of water leaking
backwards through the closed valve.
Thereafter, a quarterly visual inspection should be
performed.
watching
the
external
Repeat
achieved
when
the
TROUBLESHOOTING
•
Shaft packing leakage
Tighten packing gland nuts equally just
enough to stop leakage, no more than ½ turn
at a time.
Replace packing if necessary.
•
Leakage past seat when closed
Inspect valve for debris, clean
Inspect seating surfaces for damage, replace
as necessary
•
Leakage past cover or flange gaskets
Tighten cover or flange bolts
•
Disc oscillating when open
Move counterweight(s) toward shaft
•
Valve slams upon closing
Move counterweight(s) toward end of arm
Ensure shaft packing is not too tight
Ensure
cushion
operates freely
Install additional counterweight(s)
Removing the valve from the line or disassembling
the valve while there is pressure in the valve body
may result in injury or damage to the valve
Follow all applicable safety regulations and codes and
read and understand all instructions before
undertaking disassembly.
DISASSEMBLY
All Figure 250 valves can be serviced while the body
remains connected to the pipeline.
technician should perform all work. No special tools
are required.
First ensure there is no pressure within the valve and
operating equipment is tagged and locked out. Refer
to page 4 for parts identification.
It is not necessary to disassemble the entire valve to
replace the shaft packing, follow steps 1 to 3. To
install packing follow steps 5a and 6a.
To move counterweight and air-cushion chamber to
left hand side of valve, disassemble valve through
Step 7. Remove cushion chamber screws (21) and
cushion chamber assembly and install on opposite
side of valve.
1.
Ensure there is no pressure within the valve
and operating equipment is locked out.
2.
Mark the position of the counterweight(s) on
the arm.
screw (31A) and slide the weight(s) off the
arm. Remove the lever cotter pin (29C) and
lever pin (29B). Loosen the counterweight
arm set screws (30A) and the lever set
screw (29A) and slide the arm (30) and lever
(29) off the shaft, being careful not to lose
the key (30B).
2
DO NOT OVER-TIGHTEN!
chamber
and
linkage
WARNING
WARNING
A skilled
Loosen the counterweight set
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