LCV [en-US]
20
6.2
Start-up
WARNING
Start-up, shutdown, filling and draining procedures must be designed to prevent any possibility of negative
torque being experienced on the pump shaft. Negative torque can cause the impeller to unscrew, leading to
severe damage throughout the rotating assembly and drive train. In particular, the following practices must be
avoided:
1) Any flow through the idle pump, in any direction, in excess of 5% of the normal operating flow rate before
the impeller has been tightened by running under normal loads. This includes flow due to filling or draining
of the system and/or flow caused by the equalization of different levels between the sump and discharge
line after the opening of any valves in the piping.
2) Any attempt to restrict the flow after shutdown, by either manual or automatic systems, until the pump
comes to a complete standstill.
3) Any braking or re-energizing of the drive train after shutdown, until the system has reached a complete
static condition.
Prolonged operation at zero or low flow, typically due to closed valve or unintended pipeline blockage, is not
permitted. Danger of steam generation and explosion.
Start-up and shutdown procedures must be designed to prevent any possibility of water hammer. Water hammer
can place excessive loads on the piping, resulting in damage to the pump flanges. The pressure waves
generated by water hammer can also cause damage to the pressure containing components of the pump, the
mechanical end and/or the mechanical seal.
CAUTION
During the initial commissioning, once the pump and bearing assembly stabilize at normal operating
temperature, or in the event of system leaks, stop the unit and re-tighten all bolts. Check the coupling alignment
and re-align if necessary.
The pump may be started up against a closed discharge shut-off element. Once the pump has reached full rotational
speed, open the discharge valve slowly and adjusted to the duty point.
When starting up against an open discharge-side shut-off element, take the resulting increase in input power
requirements into account.
Once the operating temperature has been reached and / or in the event of leakages, switch off the unit and re-tighten
all bolts. Check the V-Belt alignment as described in Section 5.3.1 “Aligning the Pump / Drive Train” and re-align if
necessary.
6.2.1
Priming the Pump
WARNING
The pump should never be run dry and air intake must be minimized using proper sump design. May result in
excess temperatures and escape of medium into the atmosphere due to shaft seal failure.
Before start-up, the pump and the tank must be vented and primed with the liquid to be pumped. The shut-off element in the
suction line must be fully open.
Minimal Submergence for Priming
Size
Axial height above centerline of the
pump casing
Size
Axial height above centerline of the
pump casing
mm
inch
mm
inch
LCV 50-230
210
8.25
LCV 200-610
280
11.00
LCV 80-300
215
8.50
LCV 250-660
315
12.25
LCV 100-400
230
9.06
LCV 300-700
350
13.75
LCV 150-500
255
10.00
ZW
200
7.90
Summary of Contents for LCV
Page 40: ...LCV en US 40 14 Notes ...
