4. Operating instructions
4. 1. Commissioning and starting up the pump
B. Start Up
1. Switch on driver for a short instant, then switch it off again immediately. Observe the rotor, which should run down to a
standstill evently and smoothly. Check that the bearings are being properly lubricated.
2. Run the pump rapidly up to full speed.
3. Check that the pump attains the prescribed discharge pressure.
4. After the pump has attained full operating speed, open discharge valve and adjust it to the operating conditions required.
A. Points to be checked prior to commissioning or start-up:
1 .Check the oil level in the bearings of the pump, and if necessary replenish until the oil runs out of the over flow.
2. Check the condition of stuffing boxes. Follow the instructions for correct packing of the stuffing boxes.
3. If cooling water is provided, turn it on and check that if flows away freely.
4. Close discharge valve; check that isolating valve in the balance water line is wide open.
5. Open valve in suction line to its full extent.
6. Make sure that the pump is completely primed with liquid. Priming is effected through the priming tundish (with valve) or
by opening the by-pass on the non return valve. Watch the pressure gauge on the suction casing - the pressure in the
suction line should not be allowed to rise excessively during priming. While priming takes place, the shaft should be
rotated repeatedly by hand and the vent cock on the suction casing should be opened.
7. When operating with positive suction head, check pressure and temperature in the suction line.
8. If a non-return valve is fitted, and the pump has to be started with the discharge valve open, check that the non-return
valve is closed by the pressure in the discharge line ( e. g. boiler pressure ) on start-up. If the full discharge pressure
does not reign in the discharge line before start up, the pump should only be started against a closed discharge valve.
4.2. Su
ervision durin
runnin
1. The pump should run quietly and without vibration at all times.
2. Check the bearing temperature at regular intervals (it should remain steady). If it rises unduly, check condition of
bearings.
3. Watch the stuffing boxes; the glands should drip slightly during running.
4. If water cooling is provided, check the cooling water outlet temperature at regular intervals; a 10 °C (50 °F) temperature
difference between cooling water inlet and outlet is acceptable.
5. Avoid over loading pump and driver (this happens when the discharge pressure drops below the design figure).
6. Check the correct functioning of the by-pass non-return valve; the by-pass should open at low through puts. This can
be observed by touching the by-pass return line, which should become warm.
7. If the pump operates on suction lift, always ensure that the suction head is adequate, and that no air is entrained into the
pump, by checking the water level in the suction pit or vessel.
8. If the pump operates with positive suction head, always ensure that this head does not drop below the figure specified in
the confirmation of order, as serious damage to the pump internals might otherwise result, due to cavitation. For the same
reason, the suction temperature should never be allowed to exceed the maximum value specified. This point should be
watch particularly carefully if the pump is used for hot water duty.
9. Check the pressure in the balance water line and the shaft position the position indicator at the stub end, at the regular
intervals.
10. If standby pumping sets are installed, it is advisable to operate all the pumps on a rotation system thus giving each pump
in turn a certain amount of operational duty; this ensures that the standby pump will always be in good condition for
instant start-up if required.
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