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3.7 MultiFunction Valve Operation
The MultiFunction Valve is optional on select EZ pumps and replaces the standard Manual Air
Vent Valve when ordered. It integrates the air venting/bleeding functions with a back pressure
and anti-siphon valve.
Air Vent / Bleed Function
1. Open the air vent by turning the air
vent adjustment knob counter-
clockwise one to one and a half turns.
2. Operate the pump until all of the air
is purged and only liquid is
discharged from the air vent drain.
3. Turn the air vent adjustment knob
clockwise until it bottoms out and
will not turn further.
Back Pressure / Anti-Siphon Valve
1. A spring-loaded diaphragm
automatically adds 30PSI of back
pressure to the discharge side of the
pump when the air vent adjustment
knob is closed.
2. If back pressure is not observed, the
pressure release knob may be in the
release position (the knob is resting in
its ‘up’ location). If this is the case,
turn the knob clockwise until it
‘clicks’ down (approximately ¼
turn).
3. The diaphragm prevents siphoning of chemical through the pump.
Pressure Release
1. Stop the pump operation.
2. Turn the pressure release knob clockwise until it ‘clicks’ into the release or ‘up’ location
(approximately ¼ turn). If the knob is turned too far, it will ‘click’ again return to the back
pressure or ‘down’ position. If this happens, keep turning the knob clockwise until it ‘clicks’
one time in the release (‘up’) position. Note: To avoid damage, do not turn the knob counter-
clockwise.
3. Turn the air vent adjustment knob counter-clockwise one or one and a half turns to release
the pressure in the discharge tubing/piping through the air vent drain. The air vent drain
should always be plumbed back to the supply tank or to safe disposal. Do not submerge the
air vent drain tubing under chemical in the supply tank.
CAUTION:
Confirm that liquid is discharged from the air vent drain. If the liquid is not
discharged, the pressure may not be released. If this is the case, repeat the Pressure
Release procedure.
Air Vent
adjustment
knob
Air Vent
drain