Warning - Correct Use Of Rotary Pumps - Sanremo F18 Livret D'instructions

For installation, use and
maintenance of the water
softener, follow the instructions
in the relative manual.
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7.2 WARNING – CORRECT USE OF ROTARY
PUMPS
1) Proper Alignment of Pump and Motor
On occasion the noise of a motor-pump assembly
is caused by a poor alignment.
When the coupling between motor and pump is
rigid, the pump rotor and the motor rotor may be
out of axis. If this condition is maintained over time
the most likely damage is seizure of the pump.
An efficient solution of this problem is the use of
an elastic coupling between pump and motor.
SANREMO supplies an optional kit code N.
10051020
Connections
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11
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2) Quality of Water
Tight mechanical tolerances of components and
materials used for rotary vane pumps require a
very clean water, free from suspended particles.
Sand, deposits on connecting pipes or the resins
of the sweetener, when flowing through the pump,
may scratch graphite parts causing problems of
insufficient pressure and flow rate.
If a closed loop hydraulic circuit is not available
to guarantee a clean water and no sources of
contamination SANREMO recommend to install a
5-10 micron filter between the sweetener and the
pump.
Recommended filter: food approved polipropilene
wire cartridge.
Keep the filter clean: an upstream dirty filter will
create cavitation and the pump will break shortly
(see section 4).
3) Dry operation
Rotary vane pumps may operate in dry condition
only for a very short time- few seconds!
Without a proper water cooling the temperature
of the mechanical seal will increase very quickly
with resulting breakage. The most likely impact is
a remarkable leak visible from the four drain holes
close to the motor clamp. For potential lack of feed
from city water line SANREMO recommend the
installation of a minimum pressure safety switch
upstream from the pump.
In case of feed from a tank install on the tank a
minimum level switch.
4) Cavitation
Cavitation shows when feed flow rate does
not match the pump design requirement: most
frequent causes are dirty filters, small diameter
pipes, more users on the same line.
Opening of the safety valve (generally installed
upstream from pump and filter) must happen
before the pump start up. This will avoid cavitation.
For the same reason closing of the safety valve
must be delayed after the pump shut down.
The most noticeable effect is an increase of noise.
If cavitation continues the impact is the same as of
dry operation.
5) Back Feed of Hot Water
If a non return valve between the pump and the
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F18
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