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As the valve opens it freely draws oil from the
reservoir into the piston chamber.
When the system pressure subsides the force of the
counterweights will close the valve, forcing oil back
into the reservoir through a flow control valve to
control the speed at which the valve closes.
VALVE CONSTRUCTION
The standard Figure 525-RD surge relief valve has an
epoxy coated cast iron body and steel cover, stainless
steel body seat, stainless steel shaft and resilient disc
seat.
The valve incorporates a self-contained hydraulic
system to control the speed at which the valve closes
after opening to relieve excess pressure.
Refer to the List of Materials submitted for the order if
non-standard materials were provided.
Refer to Page 4 for details of construction and parts
location.
START-UP
The valve generally does not require any calibration
or adjustment prior to start-up. The pressure at which
the valve opens is set at the factory per the
Engineer's specification and indicated on a tag wired
to the valve. This pressure is typically 10% higher
than the highest pressure that would be present at the
valve's inlet.
The valve is shipped from the factory with the oil
reservoir full of oil and a pipe plug in the fill port to
prevent spillage during transit and installation.
IMPORTANT: Prior to start-up remove the pipe plug,
check to make sure reservoir is ¾" full and replace
with the blue plastic vented plug that is wired to the
reservoir.
If additional oil is needed, use AW32 Hydraulic Fluid.
The closing speed flow control valve (28) should be
initially opened ¼ turn from closed.
Since the relief valve's opening pressure is always
higher than the "normal" pressure, an abnormally high
pressure is needed to test the valve's operation.
This may be accomplished by throttling valve but
most of the time the pumping system is started then
shut down and the reaction of the relief valve is noted.
If necessary, the pressure at which the valve starts to
open can be field adjusted by loosening the
counterweight set screws (12) and incrementally
moving all the counterweights on each side an equal
distance farther from the shaft to increase the opening
pressure and closer to the shaft to decrease the
opening pressure. Tighten the set screws once the
counterweights are re-positioned.
variables involved there is no "calibration," so field
adjustment is by "trial and error."
Because of the structural limitations of the valve, the
opening pressure cannot be set higher than that
noted in the below table:
Small adjustments to the closing speed may be made
if needed. Loosen lock nut on closing speed flow
control valve (28) and turn screw clockwise to slow
closing speed, counterclockwise to increase closing
speed.
CAUTION: Do not completely close the needle valve
as this will prevent the relief valve from closing once it
has opened.
PREVENTIVE MAINTENANCE
Figure 525-RD sewage surge relief valves require no
routine
maintenance.
A monthly inspection should be performed for the first
6 months of operation to ensure there is no external
fluid leakage or audible evidence of water leaking
through the closed valve.
Thereafter, a quarterly visual inspection should be
performed.
TROUBLESHOOTING
Due to the
2
Maximum
Size
Set Pressure
2"
175 PSI
2½"
100 PSI
3"
100 PSI
4"
6"
8"
10"
12"
lubrication,
adjustment,
•
Valve Fails to Open at Desired Pressure
- Set pressure too high – adjust weights
- Inlet isolating valve closed – open valve
•
Valve Fails to Close
- Set pressure too low – adjust weights
- Closing speed valve closed – adjust ¼ turn
open
- Closing speed hydraulic tubing kinked or
clogged – repair/replace/clean tubing
•
Leakage Through Valve When Closed
- Debris lodged under seat – inspect/clear
- Damaged disc seat – inspect/replace
•
Valve Closes Erratically
- Low or no oil in reservoir – fill ¾ full when
valve is closed
- Trapped air – bleed (see page 3)
- Damaged piston seal (21) – replace
• Oil Leakage
- Worn piston seal - replace
- Leaking fitting – seal and/or tighten
70 PSI
30 PSI
15 PSI
10 PSI
7 PSI
or
preventive
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