Liquid Controls MS Meters - Manual (Page 15)

15
Meter Maintenance
RELIEVING INTERNAL PRESSURE
All internal pressure must be relieved to zero before disassembly or inspection of the strainers,
air eliminators, valves, the pulse output device (POD), or the front and rear covers.
Serious injury or death from fire or explosion could result from maintenance of an
improperly depressurized and evacuated system.
Procedure for Non-LPG Meters
1. Turn off pump pressure.
2. Close valves before and after the meter.
3. Remove pressure by cracking open the drain plugs until pressure is relieved. Then open the
drain plugs completely and drain the meter.
Procedure for LPG System Meters
1. Close the belly valve of the supply tank.
2. Close the valve on 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 dispenser manufacturer for procedures to depressurize
the system.
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. Open the bleed valves located on the strainer cover and meter cover (if equipped) to relieve
pressure in the system. Product will drain from the meter system.
Caution: If the systems contains a Back Check Valve, pressure inside the meter
housing MUST be relieved by opening the bleed valve in the meter cover (if
equipped) or by loosening one of the pipe plugs in the meter cover. This
procedure must be done for each meter.
7. As product is bleeding from the bleed valve, slowly reopen and close the valve/nozzle on the
discharge line. Repeat this step until the product stops draining from the bleed valve and
discharge line valve/nozzle.
! ! ! ! ! WARNING