VARISCO DUO JD - Page 24

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INSTRUCTIONS FOR THE USE AND MAINTENANCE - DUO JD
Problem Cause Remedy
13.3 Pump does not deliver enough
liquid
Air leaks in suction line Check joints are airtight and inspect
suction pipe
Impeller and/or wear plate may be worn Replace them by disassembling
the pump as described in sections
10.2 and 10.3.
Diameter of the suction pipe too small Replace suction pipe. Refer to
section 13.2 for other possible
causes.
13.4 Pump does not provide enough
pressure
Viscosity of the liquid is higher than
expected
Contact the pump manufacturer
once you have measured the
viscosity of the liquid.
Viscosity for centrifugal pumps
should not exceed 50 cSt.Check
for other possible causes: see point
5 in section 13.1, and section 13.2
13.5 Pump absorbs too much power Rotation speed too high
Check correct rotation speed
Pump operates under conditions that
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contract
Check operating conditions of pump
and compare them to those on the
pump’s nameplate
Density of the liquid is higher than planned Measure density of the liquid and
compare it with the agreed value
There may be friction inside the pump between
rotating and non-rotating components
Disassemble pump casing as
indicated in sect. 10.2 and check
for scratches on surfaces
Foreign matter in the impeller Disassemble pump casing as
described in section 10.2 and
remove foreign matter
13.6 Pump vibrates and is noisy 3XPSLV RSHUDWLQJZLWKDÁRZUDWHWKDWLV
too low
Check settings of the valves in
the system and readings on the
pressure and vacuum gauges
3XPSRUSLSHZRUNLVQRWÀ[HGVHFXUHO\ Make sure system pipework is
correctly fastened
Pump cavitates Check possible causes: see section
13.1 and 13.2
Foreign matter in the impeller Disassemble pump casing as
described in section 10.2 and
remove foreign matter
13.7 Pump jams Foreign matter in bearings Inspect impeller, disassem-bling
the pump casing as indicated in
section 10.2
13.8 Bearings do not last Foreign matter in the impeller Replace bearings
Bearings are rusted Replace bearings
13.9 Seal leaks 1-2 seal
This type of seal is suitable for
pumping dirty liquids or liquids
containing abrasive particles and
petroleum products with temperatures
up to 110°C: check level of grease
in lubricator at regular intervals. If
well lubricated, it can run dry for 2
minutes. If the pump leaks during
operation, the seal must be replaced
(see section 10.4)
13.10 Seal overheats The pump does not prime See section 13.1 and 13.9