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The float switch cable is to be attached to the discharge pipe in such a way that the remaining free cable length ensures a sufficient flow volume. The pit size should also be taken into account. In addition, it must be ensured that the depth of the pit is sufficient for the switch-on/switch-off spacing of the float pit and that the spacing between the pit bottom and the inlet is at least 60 cm.
Yes, absolutely. The installation and operating instructions contain basic instructions which must be followed in connection with the installation, operation, and maintenance of the system. Hence, they must be read by the installer and the relevant personnel/owner prior to installation and commissioning. In addition, they must be available to personnel on site at all times.
When a pump operates too far to the right on the curve, this simply means that the pump is delivering a flow rate greater than that for which it was designed. In other words: The pump is too small for the volume flow needed by the system. Operating the pump in this range may cause damage to the pump and the motor.
The pump must always be operated within the lower and upper flow rate bounds. Ideally, the pump should be operated as close as possible to the point of optimal efficiency in order to ensure a long service life and in order to minimize energy consumption.
The pump must always be operated within the lower and upper flow rate bounds. Ideally, the pump should be operated as close as possible to the point of optimal efficiency in order to ensure a long service life and in order to minimize energy consumption.
If the pump is operating too far to the left on the curve, this simply means that the pump is delivering high pressure but at a flow rate that is low or non-existent. High pressure inside the pump stresses the impeller unit and thus increases pressure on the motor bearings. In the extreme case, this will cause damage to the pump and motor.
If the flow rate is below the minimum flow rate required for the pump, the pumped medium may also overheat and damage the pump. For this reason, the pump must always be operated inside the lower and upper flow rate bounds. Ideally, the pump should be operated as close as possible to the point of optimal efficiency in order to ensure a long service life and in order to minimize energy consumption.
Dry running of the pump can damage the mechanical seal and the motor. For this reason, the float switches should be arranged so that the fill level in the shaft does not fall below the minimum level required to operate the pump. (See also ‘What minimum fill level is required to properly operate the pump?’). The actual conditions prevailing in the application in question must therefore always be reconciled with the information provided in the operating instructions or the datasheet before initial start-up of the pump.
Our highly trained Grundfos Service and Solutions Engineers will do the commissioning of the distributed pumping solution, which includes:
- A pre-commission visit, ensuring the installation of the pumps are in order.
- Initial configuration of the pumps according to the specifications in the design.
- Solution commissioning, ensuring the whole system is operating as per designed.
Water hammering is a pressure surge caused by a rapid change in flow velocity in the pipeline. This phenomenon is referred to as "water hammering" because the pressure surges are frequently accompanied by a noise that sounds as if the pipeline were being pounded with a hammer.
In well installations, water hammering generally occurs if a) the non-return valve in the downpipe extending down from the pump is installed more than 9 m above the water level, or b) the non-return valve installed in the downpipe extending down from the pump is leaky, while a non-return valve fitted above that level stays tight. In both cases, a partial vacuum is created in the downpipe. The next time the pump is started up, water fills the vacuum at high flow velocity and presses against the closed non-return valve and the stationary water column in the pipeline, thereby causing a pressure surge or water hammering. This pressure surge may cause pipelines to burst and pipe joints to break, and may damage the pump and/or the motor. If pressure surges do occur, the system should be switched off, and the pump installer should be brought in to resolve the problem.
A drainage pump is primarily intended for pumping surface water and seepage to different locations, and for the pumping of groundwater. Wastewater pumps on the other hand are primarily used to dispose of wastewater. This includes e.g. pumping wastewater out of collector pits and pumping station applications.
The two pump construction types differ primarily in terms of free passage, i.e. the maximum permissible particle size of the solids contained in the wastewater. Wastewater pumps generally have larger free passage then drainage pumps.
Cavitation is the formation and abrupt collapse of vapour-filled bubbles. This process takes place at points inside the pump where the pressure falls below the vapour pressure of the pumped medium. The vapour pressure of a liquid is the pressure at which the liquid begins to boil or evaporate. Cavitation, which may damage the pump, occurs when the net positive suction head (NPSHR) needed by the pump is not available.
In order to avoid cavitation, a minimum pressure referred to as the net positive suction head available (NPSHA) must be present at the suction port so that the liquid does not boil or evaporate. It must be ensured that the pressure applied at the suction port is always greater than the vapour pressure of the liquid at a given temperature of the medium.
Note: If a pump cavitates, the control valve on the pressure side should be throttled in order to reduce the flow rate and thus the NPSH value required by the pump. However, it must be ensured that the flow rate remaining is large enough to sufficiently cool and lubricate the pump.
The NPSH curve displays the minimum required inlet pressure (expressed in m) allowing the pump to pump in accordance with the performance curve and in order to prevent evaporation of the pumped fluid so as to avoid cavitation inside the pump.
At a given flow rate, the NPSH value available at the pump's suction ports must always be at least 0.5 m greater than the required NPSH value: NPSHA > NPSHR + 0.5 m safety margin
In a dry-running pump, the component that comes into contact with the medium (the wetted part) is separate from the motor. The seal of the pump shaft in the wetted part is provided in the form of a mechanical seal. The pump is driven by a motor connected to the pump shaft by a coupling.
Because a Grundfos Distributed Pumping system is replacing the valves with coil pumps and reduces the kW size of primary pumps, the Capital Investment will either be the same as a conventional system or around 20% more expensive, depending on the choice of valves in the conventional design.
But the commissioning efforts needed for a Distributed Pumping Solution, will be much less, since there is no need for hydraulic balancing or determination of Set Points (ie. Constant differential by-pass pressure set point) With the energy savings and easy commissioning of a Distributed Pumping Solution, the Return of Investment is kept below 6 months.
Grundfos Distributed Pumping is made possible with our connected pumps that gives optimal and intelligent distribution of chilled water to all terminal units.
For supplying each terminal unit, we utilised our MAGNA3 range as coils pumps. The MAGNA3 is a canned-rotor type, i.e. pump and motor form an integral unit without shaft seal and integrated variable speed drive and IE5 motor giving you the most efficient pump within its' class and it doesn't require maintenance. The MAGNA3 comes with all the needed control algorithms to modulate the chilled water flow as the heat load of the building changes, by using external temperature sensor to maintain constant supply or return air temperature.
For primary pumps we are able to drastically reduce the pumping power rating (kW) since they now only need to circulate the water in the primary side up to the de-coupler. We recommend using our in-line TPE range with IE5 motors and integrated VFD. The advantage of these pumps, are they don't require alignment and are perfectly balanced, giving the shaft-seal a much better lifetime.
Grundfos Distributed Pumping solution is the new revolutionary offering for distribution of chilled water in HVAC applications without the need for pressure regulating valves. With a distributed pumping solution, you will gain:
- Up to 50% energy savings on your annual pumping power use by using the worlds’ most energy efficient pumps.
- Flow-driven pumping solution that gives you just the right flow to meet your heat load demand.
- Valve-less design, reducing system pressure and eliminating the need for costly balancing.
Grundfos service specialist shows how to dismantle and assemble Grundfos CR, CRI, CRN 10, 15, 20 (IEC).
Note: All the services that are demonstrated in the video are for knowledge purpose, however service supervision is recommended and we are not responsible for the damages incurred as a result of DIY.
Video – CR Service
Grundfos service specialist shows how to dismantle and assemble Grundfos SCALA2.
Note: All the services that are demonstrated in the video are for knowledge purpose, however service supervision is recommended and we are not responsible for the damages incurred as a result of DIY.
Video - Scala 2 Service
Grundfos service specialist shows how to repair Grundfos CM, CME 1, 3, 5, 10, 15, 25 (cast iron).
Note: All the services that are demonstrated in the video are for knowledge purpose, however service supervision is recommended and we are not responsible for the damages incurred as a result of DIY.
Video - CM Service
Grundfos service specialist shows how to install Grundfos Sololift2.
Note: All the services that are demonstrated in the video are for knowledge purpose, however service supervision is recommended and we are not responsible for the damages incurred as a result of DIY.
Video - Sololift Service