Val-Matic Swing-Flex Check Valve - Manual (Page 7)

BOTTOM MOUNTED OIL DASHPOT FIELD INSTALLATION AND MAINTENANCE
(OPTIONAL)
DASHPOT FIELD INSTALLATION: The bottom
dashpot is supplied as an optional assembly from
the factory. This unit provides control of the disc’s
final 10% travel to the closed position to reduce
valve slam and water hammer. The 10% travel
time is adjustable between 1 and 5 seconds.
1. Depressurize and drain the valve and pipeline.
2. Score the coating around and remove the pipe
plug in the bottom boss of the valve. Apply
Teflon thread sealant or tape to brass threads
on the dashpot.
3. Insert the threaded end of the assembly into
the valve boss. Slowly turn the assembly into
the boss taking care not to cross-thread the
bushing. Continue turning the assembly into
the valve for a tight fit and so that the tank is
upright.
4. Adjust the air pressure in the tank to be a
minimum of 50 psi over the line pressure. Set
the flow control valve in the mid position (i.e. 1
turn open). The dashpot rod should be
extended and hold the disc open about 1 inch.
The water line pressure will close the disc.
FIGURE 6. BOTTOM MOUNTED OIL DASHPOT
CHECKING OIL AND GREASE LEVELS:
1. The check valve should be closed.
2. The air in the oil reservoir must be bled from
the reservoir, using the air fill valve mounted on
the reservoir.
3. Remove the pipe plug from the oil reservoir fill
port.
4. Add hydraulic fluid equal to Mobil #DTE 24 until
fluid is up to level indicated on the reservoir.
Replace pipe plug.
5. Recharge the reservoir with air pressure to a
minimum of 10 psi over the water line pressure.
6. The grease level cannot be checked but it is
recommended that the grease fitting be
charged with grease twice a year. Use a
cartridge grease gun and pump grease into the
fitting using two full strokes. An FDA approved
grease such as Lubriko #CW-606 should be
used (Master Lubricants Company,
Philadelphia, PA)
DASHPOT SEAL REPLACEMENT: There are
several seals in the unit that may require
replacement.
1. Depressurize and drain the valve and pipeline.
2. Unscrew the dashpot from the valve and
remove the 4 bolts holding the dashpot spacer.
3. Replace the (2) rod wipers and o-ring seal.
4. If the oil cylinder is leaking oil, tighten the tie
rod nuts. The cylinder should be returned to
the factory for rebuilding.
5. Reinstall the unit as listed above for a new unit.
WARNING
Removal of the bottom plug in the valve
while under pressure may cause bodily
harm.