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4.2. Three-phase pumps
GQR, GQS, GQV, GXC, GXV
Cable without plug.
Install in the control box an overload-protective de-
vice in accordance with the name-plate current.
With three-phase pumps, when the water level is
not under direct visible control, install a float switch
connected to the control box and to set the water
levels to stop and automatically start the pump.
4.3. Three-phase pumps GMC, GMV
Cable without plug.
Fitted with 2 thermal protectors which are connected
in series and inserted between two different phases.
The thermal protectors, in the three-phase motors,
provide protection against overloading and not
against operation with a blocked rotor.
The control box must therefore also be fitted with
a suitable hot-wire ammeter relay cuopled with
the control contactor.
Electrical diagram pag. 54.
5. Starting
With a three-phase power supply make sure the
direction of rotation is correct.
Before installation, momentarily start the motor to
check through the suction opening that the rotation of
the impeller is as shown by the arrow on the pump.
Otherwise disconnect electrical power and reverse the
connections of two phases in the control box.
Operation with wrong direction of rotation will cause
vibration and loss of delivery capacity.
Reverse rotation can also demage the mechanical
seal.
When in doubt, take the pump out of the water and
check rotation of the impeller by sight.
Never introduce fingers in the suction opening
unless it is absolutely certain the electric power has
been disconnected (that the pump cannot be acci-
dentally switched on) and the impeller has stopped
rotating completely.
The motors with supply current direc-
tly switched by thermally sensitive
switches can start automatically.
Never take the pump out of the water whi-
le the pump is still operating.
Avoid running dry.
Construction with float switch: the float switch
connected directly to the pump controls starting and
stopping.
Check that the float switch is free from any obstacle.
Construction without float switch: start the pump
only if fully immersed in the liquid to be raised.
The Single-phase motor will stop if operation is
prolonged with water at a temperature above 35 °C.
When the windings cool down, the thermal protec-
tor enables restarting.
Relief valve for GQR, GQS, GQV: the pump is
fitted to a relief valve for air release around the
impeller granting a proper pump priming also
after long standstill periods.
6. Maintenance
If there is a risk of freezing, take the pump out of
the water and leave in a dry place.
When used with muddy liquids, run the pump briefly
with clean water to remove all deposits immediately
after use or before a period of inactivity.
Check periodically that the relief valve item 14.80
is not clogged by impurities. If required, remove
the screws 14.24 and the fixing ring 14.22.
INSTRUCTIONS FOR SAFETY, HYGIENE AND
HEALTH PROTECTION AT WORK.
Disconnect electrical power before
any servicing operation and make
sure
the
pump
cannot
be
accidentally switched on.
The pump may have been immersed
in hazardous substances or products
emanating toxic gases, or may be
located in an environment which is
toxic due to other reasons; make sure
all necessary precautionary measures
are taken to avoid accidents.
Any pumps that require inspection/repair
must be drained and carefully cleaned inside
and outside before dispatch/submission.
Hose down all accessible parts with a jet of water.
7. Dismantling
For disassembly and reassembly, refer to the cross-
section drawing pag. 52, 53.
The pump function can be impaired by erro-
neous procedure or tampering with internal
parts.
For GQR, GQS, GQV
To inspect the impeller (28.00), to clean the internal
parts and to check whether the impeller turns freely
when moved by hand, remove the screws (15.70
GQR) or strainer (15.50 GQR), the screws (14.24)
pump casing (14.00).
To dismantle the impeller remove the nut (28.04).
Others parts should not be dismantled.
For GXC, GXV, GMC, GMV.
To inspect the impeller (28.00), to clean the
internal parts and to check whether the impeller
turns freely when moved by hand, remove the
nuts (GX) or the screws (GM) (12.20) and casing
cover (12.00).
To dismantle the impeller remove the nut (28.04).
Use the threaded dismantling holes to remove
the GMV impeller.
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