Pressure Tanks - Grundfos BMQE 15 Product Manual

Handbook

Pressure Tanks:

Tanks are provided with the EZ Boost and MQ systems. The EZ Boost has an external tank and the MQ an internal tank. The
Basic Line however may need a tank depending on your application. In order to minimize the number of pump starts and
stops in the water supply system, and to reduce problems with water hammer in the pipe work, a pressure tank should be
installed.
Pressure Switches:
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 respectfully. The EZ Boost comes with a pressure transducer for constant pressure. The MQ has a built-
in pressure switch. Basic Line Jets have the pressure switch attached.
Valves:
Check valves: The EZ Boost and MQ systems have built-in check valves. When doing a suction lift with the MQ a check
valve is required at the inlet. This check valve is provided with every MQ.
Foot Valves: When pulling a suction lift (shallow or deep well) with the Basic Line a foot valve is required. This valve
is installed at the end of the suction pipe to prevent back flow. The MQ will also benefit from the use of a foot valve
when doing suction lifts.
Shut off valves: Use shut off valves in the piping system in such a way to make it possible to drain only the part of the
system that needs attention or repair.
Flow control valves: Used in applications where a set amount of flow (gallons per minute) are required. An example
of this would be a shower head or an irrigation system.
Pressure reducing valves: Used in applications where the incoming water pressure exceeds the maximum inlet pres-
sure of the pump as is the case with the MQ and city water pressure. The Pressure Reducing Valve or PRV is used inline
after the city water tap and before the pump to ensure a set pressure.
Pressure relief valves: This valve is a spring controlled devise that can be adjusted to meet the needs of the pumping
system. Used in applications where high pressure can result in damage to accessories such as tanks where there are
maximum pressure ratings.
Theory:
Matching consumption and pump capacity:
Selecting the right pump is a matter of matching water c onsumption with pump capacity. Installing an under or
oversized pump should be avoided. Consumption varies greatly d epending on housing standards and lifestyle. Garden
watering in the summer can increase consumption.
Pump Selection:
Pump selection is based on the water demand and the system h ead. The water demand depends on the number of
consumers connected to the system. Head can either be expressed in feet or P SI. Head refers to static head, pressure
head, and friction head. For assistance in Pump Selection refer to the WebCAPS selection p rogram found on the
Grundfos web site.
Piping:
In any water supply system, the sizing and choice of materials of t he pipe work has an impact on the choice of pumps
and on the cost. Piping takes into account the system head as referred to in P ump Selection. Static head is the distance
from the ground water level to the uppermost tap. Pressure head is the system p ressure the customer wants to achieve.
I n most residential application this pressure is approximately 60PSI. Friction head depends on the pipe size, type and
length. When calculating friction loss always remember to allow for deterioration in the piping schematic as all water
pipes will eventually become coated with rust, lime deposits, etc. Flow velocity in the piping must be kept low as noise
can occur due to turbulence in elbows and valves or from water hammer. Fitting a pressure relief valve in the discharge
piping is recommended to protect the piping from over-pressure due to system malfunction.
Accessories
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