14
Operating precaution
1. Before starting operation.
(1) Clean pipes and tanks. If foreign objects enter the pump, not only the performance decrease, but
also cause a breakdown.
(2) Pour priming water from the priming water plug on the top of the suction casing and release air.
From next time, it is not necessary to do it for the self-priming structure.
(3) Check that the flange bolts are tightened firmly. Loose bolts may cause liquid leakage, injury to
people and damage to other facilities.
(4) Check the rotation direction of motor. If the motor rotates in reverse, rewire two phases of the
three-phase power supply. It is clockwise as viewed from the motor fan.
(5) Tighten the drain plug more. If it is loosened at the start of the operation, the self-priming ability
decreases dramatically and it may cause the pump damage.
2. No dry running.
Sliding parts are cooled by self-circulation with pumped liquid. If the pump is operated with no liquid, it
may damage by heat. If dry running occurs, do no suddenly pour liquid in it rather than leave it an
hour and more. A sudden flow of liquid may rapidly cool the heated sliding parts and severely
damage them beyond repair.
3. Liquid seal operation by mistake (Suction & discharge valves are closed.)
When operating pumps with the suction & discharge valves closed, the inside is subjected to high
pressure and temperature. If the pump is disassembled in this situation, steam and hot water are
spewed. Make sure to check decreasing in temperature completely and do it.
When the pump inside is damaged by liquid seal operation, not only parts but also pump may have to
be replaced.
4. Range of the used liquid temperature
Vapor pressure, viscosity, and corrosiveness are changed depending on the temperature of the used
liquid. Use the pump under arrowing leeway of the pump performance in mind of them.
⚫
Range of the used liquid temperature:
0
– 80
℃
(32
– 176 F) <20**GV1 series>
0
– 70
℃
(32
– 158F) <GV* series>
0
– 60
℃
(32
– 140 F)<GVF* series>
* The self-priming height and time are changed depending on the liquid temperature.
5. Change of the used liquid specific gravity or viscosity
If the specific gravity and viscosity are changed a lot, the pump
’s performance capacity, efficiency,
and axial movement power may be changed by pumped liquid. Take them into consideration and use
the pump within an appropriate leeway.
6. Use conditions change
The pump is manufactured under the specification based on the meeting before purchase. If the use
condition is changed, consult us.
