Liquid Controls MA4 Meter - Manual (Page 10)

10
WARNING
Relieving Internal Pressure
All internal pressure must be relieved to zero pressure
before disassembly or inspection of the strainer, air eliminator any valves in the system,
the packing gland, and the front or rear covers.
Serious injury or death from fire or explosion could result from maintenance of an
improperly depressurized and evacuated system.
! ! ! ! ! WARNING
4. Slowly open the valve/nozzle at the end of the supply
line.
5. After product has bled off, close the valve/nozzle at
the end of the supply line.
6. Slowly crack the fitting on top of the differential valve
to relieve product pressure in the system. Product
will drain from the meter system.
7. As product is bleeding from the differential valve,
slowly reopen and close the valve/nozzle on the
discharge line. Repeat this step until the product
stops draining from the differential valve and
discharge line valve/nozzle.
8. Leave the discharge line valve/nozzle open while
working on the system.
Procedure for Non-LPG Meters
1.
Turn off pump pressure to the system.
2. Close valves before and after the meter.
3. Remove pressure by removing the drain plugs and
draining the meter.
Procedure for LPG Meters
1.
Close the belly valve of the supply tank.
2. Close the valve on the vapor return line.
3. Close the manual valve in the supply line on the inlet
side of the meter. If no manual valve exists on the
inlet side, consult the truck manufacturer for
procedures to depressurize the system.
Meter Maintenance
Prevent pipe strain or stress from occurring when making
meter or accessory repairs. Pipe strain and stress occur
when the pipes are not supported or are not aligned
correctly to the meter. The weight of the pipes must
always be supported independent of the meter. This
means that the meter and accessories can easily be
removed without affecting the pipes or the pipe alignment.
Never leave any of the pipes hanging.
Seasonal meter storage. If the meter is used for seasonal
work, at the end of each season the meter should be
removed from the system and thoroughly flushed with a
compatible liquid. This includes removing the drain on
the front and rear covers. Then flush the product from
the front and rear covers. If flushing with water is
preferred, extra care should be taken to drain the meter
completely and to dry all internal parts. Immediate refilling
with a compatible liquid (or oil misting) is essential to
prevent corrosion as well as ice damage to parts from
moisture that was overlooked after flushing and drying.
Do not mar or scratch any of the precision machined
surfaces by prying or sanding parts.
Torque specifications. All fasteners such as screws and
bolts should be torqued to proper specification. See the
“Torque Chart” on Page 25 of this manual.
Stone the machined surfaces when reassembling the
meter to assure that the machined surfaces are free of
burrs and mars.
Repair pulled threads with threaded insert fasteners.
These can be used in many instances. Contact your
full-service distributor for advice if this occurs.
Coating threads. When removing and replacing bolts
and castings in a meter, always coat the threads with
anti-seize.
Removing flange seals. When removing the flange
assembly, always carefully remove the O-ring seal. Make
sure that the flange surface is clean. Discard and replace
the old O-Ring seal if it is nicked or scratched in any
way. If it is undamaged, it can be reused.