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4.4
Multi-Function Valves
Your pump may be equipped with one of the following multi-
function valves: 3-FV, 4-FV, or standard discharge valve. If your
pump is not equipped with a multi-function valve and you feel it
is needed in your application, it can be purchased as an accessory.
Contact your local LMI stocking distributor.
4.4.1
Three Function Valve (3-FV)
1. Pressure Relief
If the discharge line is over pressurized, the valve opens
sending solution back to the supply tank.
2. Line Depressurization
Opening the relief knob provides line drain back to the sup-
ply tank.
3. Priming Aid
Opening the relief knob assists in priming the pump by
venting the discharge line to the atmosphere.
4.4.2
Four Function Valve (4-FV)
1. Pressure Relief
If the discharge line is over pressurized, the valve opens
sending solution back to the supply tank.
2. Line Depressurization
Opening the relief knob provides line drain back to the sup-
ply tank.
3. Anti-Syphon
Prevents syphoning when pumping solution downhill or into
a vacuum.
4. Back Pressure
Supplies approximately 25 psi back pressure to prevent
overpumping when little or no system back pressure is
present.
