Sanremo ZOE COMPETITION Instruction Booklet page 20

ENGLISH
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 hot water vessel is defective the pump may
come in contact with hot water(90-100°C). Dimensional variations of components will cause
seizure of the pump.
6) WRONG CONNECTIONS
Pumps connectors are 3/8"NPT(conical) or 3/8" GAS(cylindrical).
Connectors with thread different from the recommended type are occasionally used. Sealing is
made with a glue or with teflon tape. If the connector is forced it is possible to create beards; if
excess sealing glue is used the extra quantity of glue may enter into the pump body.
In both cases it is likely to create a damage.
7) PRESSURE STROKES
To avoid pressure strokes opening of solenoid valves installed downstream must happen
before the start of the pump. For the same reason closing of the valve must be delayed after
stopping of the pump.
A pressure stroke may break graphite parts and damage mechanical seal causing blockage
of the pump and leaks.
8) HANDLING
A crash on the floor may create deformations that will jeopardize the tight mechanical tolerances
of the pump components. For the same reason be very careful when clamping the pump to
mount or demount connectors.
9) SCALE BUILD UP
Scale deposits will quickly show on inner components when using hard water, not sweetened
with ion exchange resins.
Scale formation increases when the pressure relief valve is used as flow rate regulator: the rate
of scale deposition increases with increasing of closed loop circulation.
Scale deposits cause an increase of torque, occasional seizure of the pump or a reduction of
operating pressure because the pressure relief valve cannot work properly.
To minimize this problem SANREMO suggest to use pumps with flow rate matching the
hydraulic circuit features. In some circuits it is advisable to periodically remove scale with a
chemical treatment.
ZOE COMPETITION
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