Start-Up; Checking The Direction Of Rotation; Maintenance And Service - Grundfos SEN series Montage- Und Betriebsanleitung

The top cover of explosion-proof pumps is provided
with an external earth terminal to ensure the con-
nection to earth. The electrical installation must
include an external connection from this terminal to
earth. The earth wire must fulfil all electrical safety
regulations in force.
Cross section of phase
wire (S)
of the installation
[mm²]
S ≤ 16
16 < S ≤ 35
S > 35
Before installation and the first start-up of the pump,
the cable condition should be checked visually to
avoid short circuits.

7. Start-up

Before manual starting or changeover to automatic
control, make sure that no persons are working on or
near the pump.
Proceed as follows:
1. Remove the fuses or switch off the mains switch.
2. Check the oil level in the oil chamber. See section 8.1 Oil
check and oil change.
3. Check whether the impeller can rotate freely.
4. Check whether the monitoring units, if used, are operating sat-
isfactorily.
5. Make sure that the pump is submerged in the liquid.
For pumps in dry installation, it must be ensured that there is
liquid in the pit.
Make sure that the pump has been filled with the liq-
uid to be pumped.
Pumps in dry installation must be vented by means of
the vent plug in the pump housing.
6. Open the isolating valves, if fitted.
7. Check whether the system has been filled with liquid and
vented.
8. Check the setting of the level switches.
9. Start the pump and check the pump operation for abnormal
noise or vibrations.
Note: In case of abnormal noise or vibrations from the pump or
other pump or supply failures, stop the pump immediately. Do not
attempt to restart the pump before the cause of the fault has been
found and the fault corrected.
10. After start-up, the actual pump duty point must be established
as accurately as possible so that it can be checked whether
the operating conditions are as desired.
Note: The pump may be started for a very short period without
being submerged for checking of direction of rotation.
The operation of the pump should always take place in accord-
ance with established routines with scheduled checks of pump
monitoring equipment and accessories (valves, etc.). Make sure
that the pump and equipment settings cannot be changed by
unauthorized persons.

7.1 Checking the direction of rotation

An arrow cast in the pump housing indicates the correct direction
of rotation. The pump must rotate clockwise when seen from the
drive end. Observe the movement of the pump (jerk) when
started. If the pump moves counter-clockwise, the direction of
rotation is correct.
14
As an alternative, the direction of rotation can be checked as fol-
lows:
1. Start the pump and check the quantity of liquid or the dis-
charge pressure.
2. Stop the pump and interchange two of the phases to the
motor.
3. Restart the pump and check the quantity of liquid or the dis-
Minimum
charge pressure.
cross section
4. Stop the pump.
of earth wire
5. Compare the results taken under points 1 and 3. The connec-
[mm²]
tion which gives the larger quantity of liquid or the higher pres-
S
sure is the correct direction of rotation.
16
Note: The pump must only run for a short period when sus-
0.5 *S, max. 70 pended from a chain.

8. Maintenance and service

Maintenance and service must be carried out by specially trained
persons.
Before carrying out maintenance and service, it must be ensured
that the pump has been thoroughly flushed with clean water.
Rinse the pump parts in water after dismantling.
Pumps running normal operation should be inspected every
2000 operating hours or at least once a year. If the pumped liquid
is very muddy or sandy, the pump should be inspected every
1000 operating hours or every six months.
The following points should be checked:
• Power consumption
• Oil level and oil condition
When the pump is new or after replacement of the shaft seals,
check the oil level after one week of operation.
The oil becomes greyish white like milk if it contains water.
This may be the result of a defective shaft seal. The oil should
be changed if it contains water. See section 8.1 Oil check and
oil change.
Note: Used oil must be disposed of in accordance with local
regulations.
The oil chamber contains 1.9 to 3.5 litres of SAE 10 W 30
motor oil depending on pump size.
• Cable entry
Make sure that the cable entry is watertight and that the
cables are not sharply bent or pinched.
• Impeller clearance
Check the impeller clearance. See section 8.2 Inspection and
adjustment of impeller clearance.
• Pump parts
Check the pump housing, etc. for possible wear. Replace
defective parts.
• Ball bearings
Check the shaft for noisy or heavy operation (turn the shaft by
hand). Replace defective ball bearings.
A general overhaul of the pump is usually required in case of
defective ball bearings or poor motor function. This work must
be carried out by an authorized service workshop.
Note: Out of consideration for the heat-conducting ability, the
pump should be cleaned on the outside at regular intervals.
Before starting work on the pump, make sure that the
fuses have been removed or the mains switch has
been switched off. It must be ensured that the elec-
tricity supply cannot be accidentally switched on.
All rotating parts must have stopped moving.
The maintenance and service work on explosion-
proof pumps must be carried out by Grundfos or a
service workshop authorized by Grundfos.
The ball bearings must be replaced at least every
25,000 operating hours.