Product Overview

Grundfos DWS family
Domestic water supply
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1. Grundfos DWS family
The Grundfos Domestic Water Supply (DWS) family of
pumps includes:
• BMQE Constant Pressure System
• MQ Flow Based Pressure System
•Jet pumps.
This product guide offers information about each of
these product lines.
DWS applications
The Grundfos DWS family includes pumps to fit most
applications including:
• Constant pressure systems (BMQE)
• flow-based pressure boosting (MQ)
• rain water harvesting (MQ)
• pressure-switch-based boosting (Jet)
• suction lift (Jet).
C
Constant pressure systems
In constant water pressure systems, only the required
discharge pressure needs setting (fig. 1).
Cut-in and cut-out pressures do not play a role in this
system.
Discharge pressure can be set from 40 to 100 psi,
according to individual needs and piping system
limitations.
Fig. 1 In a constant pressure system, pressure does not
vary in relationship to consumption
Flow-based pressure boosting
With flow-based pressure boosting, the pump starts
automatically when water is consumed and stops
automatically when the consumption ceases. This is
accomplished via a flow switch connected to a printed
circuit board (PCB).
The pump will produce pressure in relation to the flow
rate with any incoming pressure cumulative to the total
discharge pressure (fig. 2).
Fig. 2 Flow-based pressure boosting
Rain water harvesting
Rain water harvesting is a way to store rain water for
future use — for example, watering a garden. Rain
water is collected from the roof of a home and
collected into a storage container. Pull a suction lift
using a non-collapsible suction line from the storage
container or connect the inlet of the pump to a spigot at
the bottom of the collection barrel for flooded suction.
Suction lift
High pressure water from the drive pipe passes
through the venturi and pulls water from the well into
the ejector, then pushes it up to the pump. This makes
it possible to push water up to the pump from depths
greater than 25 feet or to boost the output from a
shallow well pump to higher pressures.
Fig. 3 Suction lift pressure boosting
Pressure-switch-based boosting
Pressure switches are used to control pump operation.
These switches have a cut-in pressure and a cut-out
pressure to turn the pump on and off respectively.
Application
Product
BMQE MQ Jet
Constant pressure system  --
Flow-based pressure boosting -  -
Rain water harvesting -  -
Suction lift - 
Pressure-switch-based boosting - - 
TM04 9463 4310
Time
Head
TM01 9873
TM05 0823 1611
Incoming psi
Outgoing psi =
(city water pressure)
Incoming psi + performance
Suction pipe
Venturi
Nozzle
Inlet
Drive
pipe