F180 Series
3
components in the piping system create restrictions
which reduce the ow rating to less than that of the
excess ow valve rating, the valve will not give excess
ow protection, and additional excess ow valves must
be installed at these points.
2. Brass valves are not suitable for anhydrous
ammonia (NH3) applications.
3. Manually operate the excess ow 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. Polytetrauoroethylene (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 ow valve is installed, the system
should be tested for excess ow 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 ow valve is intended to
protect. There should be a sudden decrease in
ow, 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 ow
check closes.
6. To reopen a closed excess ow 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 ow
can be resumed by opening the shutoff valve.
!
WARNING
Trained personnel should test the
excess ow valve in a safe location.
Excess ow closure should be checked
annually or on a regularly scheduled
basis to insure that the valve is
still functional.
Maintenance
Excess ow valves are non-repairable. Replace
non-functioning valves.
Troubleshooting
If the excess ow 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
ow valve are restricting ow into or out of
the valve.
4. Flow capacity at point of test is not great enough
to close the excess ow 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 ow slowly to
prevent surge. A larger excess closing ow may
be required.
2. Chattering – Normal ow conditions may be too
near to the closing ow rate, or ow direction is
wrong or back owing is occuring.
3. Restriction on inlet of valve.
!
WARNING
Back owing or owing too near to the
excess ow valve closing rate may cause
chattering which may result in excessive
wear on parts and valve failure.
