Val-Matic Tilted Disc Check Valve - Manual (Page 12)

11
CAUTION
Flow control valves should not be used at
settings below the blue band (second from the
bottom). Lower settings will allow small
particles of silt present in the hydraulic fluid to
clog the valve and cause the TMOD to bind and
result in damage to the valve or dashpot.
OPTIONAL TOP DASHPOT (Cont’d)
It is recommended that the person making
adjustments to the flow control valve be familiar with
the sounds created by water hammer and valve
slam and not confuse them with the metallic sounds
created by the valve upon metal seat closure. An
over control situation should be avoided so that
cavitation (loud rumbling) does not occur. After
setting the flow control valve, tighten the locknut or
set screw on the valve. Record the flow control
valve setting and air pressure for future reference.
Valve
Size
Open FCV
Setting
Close FCV
Setting
Air
Pressure
MAINTENANCE: The Top Mounted Oil Dashpot
(TMOD) unit should be checked occasionally for the
proper air pressure within the pressurized oil
reservoir while the TDCV is in the fully closed
position. The air pressure should be maintained at a
pressure equal to 20% of the water system pressure
on the discharge or downstream side of the valve. If
the air pressure can not be maintained, the leak
within the dashpot unit must be found and corrected.
The hydraulic fluid level within the pressurized oil
reservoir and non-pressurized reservoir does not
have to be checked unless external leakage is
observed. The source of leakage must first be
repaired and then the fluid level checked. A small
amount of pipe thread sealant such as Loctite PST
should be used on clean threads to ensure a tight
joint. Allow approximately a one hour period for the
sealant to set before depressurizing the unit.
CHECKING OIL AND GREASE LEVELS:
1. The check valve should be closed. The pump
should be locked out to prevent startup.
2. The air in the pressurized oil reservoir must be
bled from the reservoir, using the air valve
mounted on the reservoir.
3. Remove the pipe plugs from both reservoir fill
ports.
4. Slowly add hydraulic fluid equal to Mobil #DTE 24
until fluid is up to the levels indicated on the
reservoirs.
Replace pipe plug with thread
sealant Loctite PST.
5.
Using the air connection, recharge the
pressurized oil reservoir to 20% of the water
pressure on the downstream side of the check
valve.
6. Restore power to the pump.
GREASE: The TMOD unit is provided with a grease
fitting located on the dashpot cover. The connecting
rod and connecting rod bushing must be lubricated
at least monthly or as conditions dictate with a
waterproof, FDA approved grease such as Lubriko
#CW-606 grease. Using a cartridge grease gun,
pump grease into the grease fitting 2 full strokes of
the grease lever. It is normal for grease to be forced
out of the rod wiper (52). If the valve is operated
infrequently, apply a thin film of grease to the
exposed surfaces of the cylinder piston rod and
connecting rod. Painting of the connecting or
cylinder rod will void the warranty.
WARNING
For valves with Top Mounted Dashpots, DO
NOT paint exposed surfaces of the
connecting rod or the cylinder piston rod or
damage will result to the hydraulic seals.