Val-Matic Tilted Disc Check Valve - Manual (Page 5)

4
MAINTENANCE
The operation of the valve can be seen by observing
the movement of the indicator pointer on the side of
the valve (6” and larger sizes). The valve should
move about 40 degrees from the closed to the fully
open position. It is normal for the valve to not fully
open in cases where the fluid velocity is less than 8
ft/sec or a Top Mounted Oil Dashpot is installed.
Dashpot assemblies require regular maintenance.
See the dashpot section in this manual.
LUBRICATION: The Tilted Disc Check Valve is
provided with grease fittings (23) located on the
pivot pin covers. The valve’s pivot trunnions must
be lubricated at least monthly or as conditions
dictate with a waterproof, FDA or ANSI/NSF 61
approved grease such as Lubriko #CW-606 (Master
Lubricants Co., Philadelphia, Pa). Using a cartridge
grease gun, pump grease into each grease fitting
using 8 full strokes of the grease gun lever.
INSPECTION: Periodic inspection for leakage can
be performed by placing a listening device or an ear
on the valve while it is closed and the line is under
pressure. If leakage is heard, close the isolation
valve and drain the valve connection, and inspect
the seating surfaces for wear or mineral deposits.
Clean or repair trim as needed.
The inspection hole covers can be removed from the
valve to facilitate internal inspection of the valve. A
hoist or jacking mechanism should be used to lift the
disc to inspect the seating surfaces. If replacement
of the disc, pivot pin bushings, disc ring, or seat ring
is required, the valve must first be removed from the
line.
TROUBLESHOOTING
Several problems and solutions are presented below
to assist you in trouble shooting the valve assembly
in an efficient manner.
TROUBLESHOOTING BASIC VALVE: The valve
opens automatically without the need of a power
source to allow forward flow. The valve may not
open to the full open position depending on fluid
velocity but it will always open far enough to pass
the flow with a minimal headloss. The valve will
automatically close to prevent reverse flow through
the pump. The valve has metal seats and a
moderate bang during closing is normal.
1. Leakage at Valve Inspection Covers (13): Re-
tighten bolts evenly or replace non-asbestos
sheet gasket.
2. Leakage at Grease fitting: Inject grease or
replace grease fitting (23).
3. Leakage at Mating Flanges: Re-tighten bolts
using the cross-over method or replace mating
flange gasket. Flange gaskets are typically 70
durometer resilient material. Check alignment
of mating pipe.
4. Valve Leaks when Closed: Flush debris from
seat by cycling valve. Verify that valve is subject
to a minimum differential pressure of at least 10
psi when closed and the isolation butterfly or
gate valve is open. If leakage persists, inspect
interior of valve. Clean seating surfaces. When
used with a power operated control valve, there
may not be sufficient reverse flow to seat the
valve. These types of installations require a
power outage for proper valve seating so that
the pump is tripped while the control valve is
open.
5. Valve Fails to Open: Check pressure differential
across disc; upstream pressure must be greater
than downstream pressure. Verify that the
suction and discharge shutoff valves are open
and there is no line blockage. Drain pipe on
both sides of the valve, remove inspection cover
(13), and inspect disc ring (8) and seat ring (10)
for damage or wedged debris.
6. Noisy Operation: Flow noise is normal. Loud
flow noise similar to hammering may be
cavitation from dropping high pressures across
valve; review flow velocity through valve and
pump application.
WARNING
Removal of inspection covers without draining
the pipeline and valve may cause serious
injury.