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MDE-4334C Atlas Start-up and Service Manual · April 2008
Hydraulic/Mechanical Components
Valves
3
Open the nozzle into an approved container to bleed pressure. Some residual pressure may
remain.
4
Use a Gasboy Atlas repair kit to replace the check valve.
5
Inspect the metallic seat of the valve body for damage or uneven seating surfaces.
6
Clean any contamination from the valve body interior.
7
Torque bolts properly. Refer to
on
.
Shear Valves
Shear valves have a section of the valve that is designed to break from an impact to the unit.
Shear valves cut-off the flow of fuel from the product piping if the impact or fire causes the
shear valve linkage to trip. Single poppet shear valves only stop fuel at the product piping.
Double poppet shear valves also stop fuel from draining out of the dispenser.
Improper wrench technique may damage the shear valve and lead to leaks. Excessive force
applied to the shear valve during fitting and tightening may damage or weaken the shear
section of valve. Always use two wrenches; one wrench to hold the valve above the shear line
and another wrench to apply force to the fitting.
CAUTION
UL requires all dispensers to use shear valves. Follow these recommendations while installing
or servicing shear valves:
• Read and follow the shear valve manufacturer’s service instructions.
• Ensure that there is free movement of the linkage.
• Lubricate the valve linkage as per the manufacturer’s instructions.
• Follow the manufacturer’s recommendations while installing the valves first.
• Shear section of valves must be flush with top of islands.
• Do not mount the valve upside down.
• Rigid cross member and mountings are important devices for proper operation of the
system. Anchor shear valves rigidly.
• Inspect valves every six months. Ensure that the valve linkage is free and clear from any
debris, conduit, piping, or any other obstruction. Lubricate the linkage with SAE 10W
motor oil.
• Gasboy highly recommends that you always use the double-poppet shear valve instead of
single-poppet when replacing valves. Use of double-poppet shear valves may require
some internal plumbing changes in older units. Double-poppet shear valves prevent fuel
from draining from the unit, which has been knocked off the island.
• Do not use pliers to open or close shear valves. Reduce the pressure if the valve does not
open easily. See the shear valve manufacturer’s instructions for proper tools and
procedures.