F180 Series
3
components in the piping system create restrictions
which reduce the flow rating to less than that of the
excess flow valve rating, the valve will not give excess
flow protection, and additional excess flow valves must
be installed at these points.
2. Brass valves are not suitable for anhydrous
ammonia (NH
3
) applications.
3. Manually operate the excess flow valve’s poppet
before installation to assure parts were not
damaged in shipment or blocked with dirt or
foreign material.
4. Use pipe dope on the male threads of the valve or
the pipeline. Polytetrafluoroethylene (PTFE) tape
or PTFE pipe dope compound is recommended for
the male threads of the larger valves such as the
2 and 3-inch sizes.
5.
After the excess flow valve is installed, the system
should be tested for excess flow valve operation
by simulating a break downstream in the system
at the furthermost point being protected. To test
the unit, pressure the system and then open a
shutoff valve quickly at the farthest point in the
piping that the excess flow valve is intended to
protect. There should be a sudden decrease in
flow, indicating that the valve has closed and is
working properly. Because of the bleed that
permits the valve to equalize itself, a small amount
of leakage will continue after the excess flow
check closes.
6. To reopen a closed excess flow valve, close a
shutoff valve on either the upstream or
downstream piping. When pressure is equal on
both sides of the valve, it will “click” open and flow
can be resumed by opening the shutoff valve.
!
WARNING
Trained personnel should test the
excess flow valve in a safe location.
Excess flow closure should be checked
annually or on a regularly scheduled
basis to insure that the valve is
still functional.
Maintenance
Excess flow valves are non-repairable. Replace
non-functioning valves.
Troubleshooting
If the excess flow valve fails to close
– check
the following:
1. Flow direction is the same direction as
arrow stamped on the valve.
2. Shut off valves on the inlet and outlet of the
piping are fully open.
3. Restrictions on the inlet or outlet of the excess
flow valve are restricting flow into or out of
the valve.
4. Flow capacity at point of test is not great enough
to close the excess flow valve.
5. Pipe scale, welding slag, or other debris is holding
the valve open.
Premature closing or valve chattering
– check
the following:
1. Surge conditions – Increase flow slowly to
prevent surge. A larger excess closing flow may
be required.
2. Chattering – Normal flow conditions may be too
near to the closing flow rate, or flow direction is
wrong or back flowing is occuring.
3. Restriction on inlet of valve.
!
WARNING
Back flowing or flowing too near to the
excess flow valve closing rate may cause
chattering which may result in excessive
wear on parts and valve failure.
