2
OPERATION - PRIMING THE PUMP
WARNING: DO NOT RUN THE PUMP BEFORE PRIMING IT, SINCE THE SEAL AND IMPELLER COULD BE
PERMANENTLYDAMAGED.
MAINTENANCE
a) PRIMING: Never operate the pump dry as this may
damage the seal. To prime, remove the priming plug and
fill the pump casing with water. Replace the priming plug
and start the unit. If an exceptionally long suction line is
used, the water in the pump casing may become
overheated or vapor locked. Should this occur, replace
the water in the pump casing with cold water and
continue priming.
b) PRIMING UNDER PRESSURE: Should it be necessary
to prime under pressure, place a check valve on the
discharge of the pump and a pet cock ball type ‘air
bleeder' in place of the priming plug, or an air bleed line
with a gate valve connected to the discharge line (see
Fig. 1). It will then be possible for the liquid to remain in
the discharge pipe and allow the pump to draw the air
bleeder thereby priming itself. In cases where the pump
has to be reprimed often and it is not necessary that a
lot of water is delivered, e.g. draining seepage from
behind a cofferdam, then it is advisable to use a 90° or
45° elbow on the suction line. This enables the pump to
prime quickly and prevents kinking or breaks in the hose.
In cases where a maximum volume of water is required
over a prolonged period of time, the suction line should
be led horizontally to the pump.
c) DRAINING: During freezing temperatures, the pump
should be drained each time it is stopped for any
appreciable length of time. To drain, remove the drain
plug at the bottom of the pump casing and make sure
that the drain hole is not plugged. After all the water has
been drained from the pump casing, the unit should be
operated for a few seconds so that all of the water will be
removed from the impeller.
NOTE: The pump should also be drained after corrosive
liquids have been pumped.
A clogged impeller results in excessive vibration. Should this
occur, the impeller must be cleaned out immediately to avoid
serious damage to the unit.
The MIT20M, MIT20H and MIT40 feature an inspection plug
in the front of the casing for visual inspection at the impeller
eye.
LUBRICATION: Lubricate the bearings with a proper ball
bearing through the grease nipples provided. Do not over
lubricate. Ball bearings require a surprisingly small amount
of grease. Over lubrication causes the bearing to break down
because the grease then tends to churn and produce heat.
If this temperature goes above 200°F, it will break down
causing the bearing to fail.
Gate Valve (min. 3/4")
Check Valve Gate Valve
Discharge
Pump
Air Bleed Line
Suction Pipe
Strainer
FIG. 1
