Grundfos BMQE 15, Product Manual, Page: 25 / 60

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PRE-INSTALLATION
A guide to the EZ Boost System
The EZ Boost Constant Pressure System automatically
balances water surges and equalizes flow and pressure
according to consumption. In other words, the system
maintains a constant water pressure in spite of varying
water consumption. The pressure is registered by means
of the pressure sensor and transmitted to the controller.
The controller adjusts the EZ Boost BMQE pump perform-
ance accordingly. The EZ Boost Constant Pressure System
features:
• Quick and easy installation: ready-to-use system
requiring minimum space
• High user convenience: constant pressure regardless of
water consumption
• Easily adjustable pressure level: push button control
• Continuous control and monitoring of pump operation
• Integrated dry-running protection
• Integrated overload protection
• Integrated protection against over voltage and under
voltage
• Soft start system
Function
When a tap is opened, the pressure in the tank will start
to drop. The system maintains a constant pressure within
the maximum pump performance in spite of varying water
consumption.
The pressure is registered by means of the pressure sensor,
which transmits a signal to the controller. The controller
adjusts the pump performance accordingly to maintain
constant pressure by changing the pump speed.
At low flow the pressure will drop slowly. When the pres-
sure in the tank is 7 PSI below the setpoint, the pump will
start. When the pressure is 7 PSI above the setpoint, the
pump will stop.
Even though the EZ Boost controller is controlling the pres-
sure within ±3 PSI, larger pressure variations may occur in
the system. If the consumption is suddenly changed, e.g.
if a tap is opened, the water must start flowing before
the pressure can be made constant again. Such dynamic
variations depend on the pipe work, but, typically, they
will lie between 7 and 14 PSI. If the desired consumption is
higher than the quantity the pump is able to deliver at the
desired pressure, the pressure follows the pump curve as
illustrated in the far right of fig. 1.
Fig. 1
At large flow rates, the pressure will drop quickly and the
pump will start immediately and maintain constant pres-
sure. When the system is running, the EZ Boost controller
makes small adjustments to the pressure to detect whether
there is consumption. If there is none, the pump will simply
refill the tank and stop after a few seconds.
Pressure
Flow
A
Stop
+7 PSI
Start
-7 PSI
Controlling
±3 PSI Dynamic
variations
±7 PSI
GPM 0.8
A = Pressure setting
Product Guide
EZ Boost TM System
24
1
2
Air escape valve
Diaphragm tank
EZ Boost controller
Isolation valve
Pressure gauge
Pressure sensor
BMQE pumps connected in parallel
When connecting BMQE pumps in parallel as shown in
fig. 5,
a separate EZ Boost controller must be used on each
BMQE . Set the pressure on one BMQE 10 PSI lower than
the other.
For BMQE pumps connected in parallel, mounted above
each other, it is recommended to connect the pipes as
shown in fig. 5. This layout ensures that the BMQE pumps
are filled with water before starting.
Fig. 5 Booster unit with two BMQE pumps
connected in parallel, mounted above each
other.
Notes:
• All BMQE modules are supplied with a non-return
valve.
• BMQE modules connected in parallel may also be
installed vertically.
• As venting problems may arise in such installations, it is
advisable to install suitable air vent devices.
• The BMQE should be positioned with the discharge and
air vent at the top when installed vertically.
• When the maximum flow for BMQE pumps in parallel
will exceed 35 GPM, a 4-gallon or two 2-gallon dia-
phragm tank(s) should be used.
Product Guide
EZ Boost TM System
25
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