Table of Contents
Advertisement
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.
VALVE CONSTRUCTION
The standard Figure 930 Air & Vacuum Valve
has a cast iron body and cover, a 316 stainless
steel float ball and Buna-N rubber seat.
to the List of Materials submitted for the order if
non-standard materials were provided.
Refer to Figure 1 or 2 on Page 3 for details of
construction and parts location.
All Figure 930 Air & Vacuum Valves have a 10
PSI minimum working pressure.
working pressure for Figure 930-DT Class 125
flanged inlet valves is 150 PSI. Figure 930-T
NPT inlet and Figure 930-UT Class 250 flanged
inlet valves have a 300 PSI maximum working
pressure.
The body (1) has an inlet connection at the
bottom where the valve attaches to the system
and an outlet connection at the top through
which air leaves the valve (during filling) and
enters the valve (during draining). The outlet
may be fitted with a "cowl" to deflect air during
venting and minimize entry of foreign matter
during air admission.
WARNING
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
PREVENTIVE MAINTENANCE
Figure 930 Air & Vacuum Valves require no
scheduled lubrication, adjustment or preventive
maintenance.
The float ball with attached float guide are the
only moving parts and require no lubrication.
A periodic visual inspection should be performed
to ensure the outlet piping is not obstructed and
to verify there is no fluid leakage.
TESTING
Valve operation can be easily tested. Close the
inlet isolation valve and remove or loosen the
pipe plug nearest the inlet to drain the water
from the valve. The float should drop as the
water leaves the valve. NOTE: A ball or gate
valve can be installed in place of the pipe plug to
facilitate testing.
Replace or tighten the pipe plug and slowly open
the inlet isolating valve. The valve should float
closed and seat tightly.
Refer
TROUBLESHOOTING
•
Maximum
•
DISASSEMBLY
Although small a size Figure 930 Air & Vacuum
Valve may be more easily serviced by removing
it from the line, all valves can be serviced while
the body remains connected to the pipeline. A
skilled technician with proper tools should
perform all work. No special tools are required.
First ensure there is no pressure within the
valve. Remove the cover screws (7) and lift off
cover (2), it may be necessary to pry the cover
off.
Remove the rubber seat (3) and lift out the float
ball (5) with float guide (8) attached. Remove
the rubber cushion (9) and flange bearing (10).
Inspect all parts for wear and damage. Minor
scratches in the float are normal. Some floats
may contain sand for added weight but if water
is detected replace the float. Clean any scale
build up from the float ball. Replace damaged
parts.
3
Valve Does Not Close / Fluid Leakage
Verify debris has not collected on the seat
preventing tight closure
Verify there is at least 10 PSI pressure at
the valve inlet
Verify rubber seat and/or float ball seating
surfaces are not deformed or damaged
Verify float guide is undamaged and
attached to float
Verify float has buoyancy
Verify float ball rises freely without
binding or sticking
Valve Does Not Open
Verify there is no debris in the valve that
is preventing the float from freely falling
when fluid is drained from valve
Advertisement
Table of Contents
