EBARA DSC4 - Manual (Page 12)

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INSTRUCTION MANUAL Model DSC4
3.6.3 Other Checks Requiring Particular Attention
(1) Minimum operating water level
Be sure that the pump stop level is not lower than the minimum operating water level
specifi ed in the technical document. If the stop level is lower, a vortex fl ow can occur
causing the pump to intake air, resulting in noise and vibration.
If there is possibility that the minimum water level may decrease to an excessive extent,
it is necessary to use a minimum water level may decrease to an excessive extent; it is
necessary to use a minimum water level alarm. An alternative measure would be a water
level-dependent automatic control system where the motor is turned off to automatically
stop the pump with the water lowered to a critical level and is turned on again to resume
automatic operation when water is restores to a safe level.
(2) Pump location relative to pump pit water inlet
If the pump is installed near the pump pit water inlet, it can be considerably disturbed;
it can be shaken and the cables whipped by vigorous inlet water, resulting in damage.
Therefore, the pump should be located as far from the water inlet as possible.
(3) Size of debris
Entry of large or long debris can result in a blocked impeller.
If such problem actually occurs, the pump can be readily lifted out and disassembled for
servicing, which is however, time and labor consuming.
The primary consideration therefore should be to prevent the ingress of any oversized
objects into the sump by use of a screen, etc. Another important consideration is to
minimize presence of abrasive substances, such as sand, in the liquid.
If the contents of such substances becomes high, the impeller is increasingly worn,
leading to the degradation of capacity.
Note: In case any problem as above actually takes place, contact us immediately.
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INSTRUCTION MANUAL Model DSC4
6. Maintenance and Overhaul
While the life of the pump depends largely on the ambient conditions, daily servicing and
inspection helps extend service life considerably. To achieve that, carry out the maintenance as
follows:
6.1 Daily Checks
Check the following items at least once a week.
(1) Current
If the ammeter reading exceeds the motor rating listed on the data plate or is abnormally
lower than usual, it is an indication of a problem.
(2) Voltage
Voltage should be within ± 10% of the rated value throughout operation.
(3) Vibration
Check for the abnormal vibrations.
(4) Protective devices
Check protective devices by reading the panel indicator.
6.2 Monthly Checks
Check the following items at least once a month.
(1) Discharge pressure
Check pump discharge pressure and discharge fl ow rate (if fl ow meter is provided).
(2) Insulation resistance
Operation is safe as long as insulation resistance is more than 2MW. If higher than 2MW,
but this occurs after a sharp decline form a certain value, check the cables, and / or
overhaul is required.
6.3 Annual Checks
Even if there is nothing wrong with the pump under normal service condition, it should be lifted
out and inspected once a year at least.
Particularly, when the pump is in use under severe conditions, such as where the liquid being
handled contains sand or is corrosive, or oversized debris is pumped through, inspect it as
often as circumstances allow.
A recommended procedure for inspection is outlined below. If mechanical seal must be replaced
or on overhaul is considered necessary as a result of the inspection, contact nearest dealer, or
us directly.
WARNING: BEFORE PULLING THE PUMP, DISCONNECT ALL CABLES AND ENSURE
THAT THE PUMP IS ISOLATED FROM THE POWER SUPPLY.
WARNING: ALWAYS LIFT THE PUMP BY THE LIFTING LUGS, NEVER BY THE MOTOR
CABLE.