Technical information

into the tank via a drilling in the cover,
thereby preventing water pressure
building up in the second chamber. The
trip lever is operated by the cam on the
end of the scale carrier.
Water entering the tank through the inlet
valve very quickly reaches the level of the
float set by the pointer, which is locked to
the scale carrier and cam. The rising
water level lifts the float/pointer/scale
carrier and cam assembly causing the trip
lever to "trip", allowing the pilot valve to
close preventing water bleeding out of the
second chamber.
Incoming water is still passing through the
orifice because it can no longer escape
past the pilot valve. Water pressure in the
second chamber increases equaling the
pressure in the first chamber allowing the
stretched diaphragm to return to its
original position, closing off the incoming
water.
A seal is maintained by the diaphragm
against the first chamber due to the
differential areas in the two chambers, i.e.
the second chamber now has a greater
effective surface area than the first
chamber.
Pulling down on the operating lever opens
the discharge valve in the base of the tank
discharging water into the drum.
Pushing up on the operating lever closes
the discharge valve, resets the trip lever
and opens the pilot valve allowing water to
enter the tank once again.
The most common symptoms of water
tank failures and their causes are:
1 Reduced water flow- blocked water
strainer or insufficient head of water or
lack of water pressure.
2 Water leaking from the discharge pipe -
worn or perished discharge valve
rubber seat or corroded valve.
3 Float failing to lift - punctured float.
4 Water flow failing to stop when pilot
valve closed - ruptured diaphragm,
worn or perished pilot valve "0" ring,
worn pilot valve, weak pilot valve spring,
blocked orifice, or excessive water
pressure.
Draining the tank
During periods of frosty weather, to avoid
damage, it is advisable to drain the tank at
the end of each day's work.
To do this, disconnect the water supply
and pull the control rod into the discharge
position.
Note: The quality of water varies
considerably throughout the world
and in some geographical regions
may cause the rapid onset of
corrosion, considerably shortening
the life of components immersed
in water.
The following simple precautions
as part of regular preventative
maintenance will assist in delaying
the onset of corrosion.
1 Drain the water tank when not
in use.
2 If the mixer is not to be used for
some time remove the tank
cover to prevent the formation
of condensation, dry out the
tank and periodically apply a
corrosion inhibitor to the
various components and
internal surfaces of the tank.
OPERATION 2.9