Danfoss APP 21–46 Installation guide
Instruction
Instruction
APP pump instruction
APP pumps
APP 21–46
APP 21-43
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Instruction | APP 21-46 pumps
Table of Contents
Table of Contents
1. Identication ...........................................................................2
2. System design ..........................................................................3
2.1 Open-ended systems with direct water supply...........................................3
2.2 Preferred RO system design and P&ID ...................................................3
2.3 Reversible pumps .......................................................................4
2.4 General comments......................................................................4
3. Building up the pump unit ..............................................................4
3.1 Mounting...............................................................................4
3.2 Direction of rotation ....................................................................5
3.3 Orientation .............................................................................5
3.4 Protection from too high pressures ......................................................5
3.5 Grounding ..............................................................................5
3.6 Connections ............................................................................6
4. Initial start-up ...........................................................................7
5. Operation...............................................................................7
5.1 Temperature............................................................................7
5.2 Pressure ................................................................................8
5.3 Dry running.............................................................................8
5.4 Disconnection ..........................................................................8
5.5 Storage .................................................................................8
6. Service..................................................................................8
6.1 Warranty................................................................................8
6.2 Maintenance............................................................................8
6.3 Repair ..................................................................................8
1. Identication
PUMP
Type APP 38
Code no. 180BXXXX
Serial no. XXXXXXXX-XXX
MADE IN DENMARK
Danfoss A/S, 6430 Nordborg, Denmark
2
180R9405 | AN274337709031en-000302 | 11.2019
Instruction | APP 21-46 pumps
2. System design
The design of the system must ensure that
self-emptying of the pump during standstill is
avoided.
The inlet pressure of the pump must never
exceed the outlet pressure. This may typically
occur in boosted or open-ended systems with
direct water supply.
2.1 Open-ended systems with direct water
supply
The pump is supplied with water directly from a
feed pump.
The inlet pressure for APP 21-38 must be at least
2 barg (29 psig) and 3.5 barg (50.8 psig) for the
APP 46, depending on speed. It must not exceed
5 barg (72.5 psig) continuous.
To protect the pump from being damaged by
peaks of high-pressure in case the pump stops
momentarily, it is required to mount a lowpressure relief valve on the inlet line.
2.2 Preferred RO system design and P&ID
1. Dimension the inlet line to obtain minimum pressure loss (large ow, minimum
pipe length, minimum number of bends/
connections, and ttings with small
pressure losses).
2. Place an inlet lter (1) in front of the APP
pump (2). Please consult Danfoss lter data
sheet for guidance on how to select the
right lter. Thoroughly clean pipes and
ush system prior to start-up.
3. Place a monitoring pressure switch (3) set
at min. inlet pressure between lter and
pump inlet. The monitoring switch must
stop the pump at pressures lower than
minimum pressure.
4. Use exible hoses (4) to minimize vibrations
and noise.
5. In order to eliminate the risk of damage
and cavitation, a positive pressure at the
inlet (5) is always to be maintained at min.
inlet pressure and max. inlet pressure.
Inlet
Outlet
It is recommend to install safety valve or a
pressure relief valve (9) in order to avoid
high-pressure peaks in case the pump stops
momentarilly or is spinning backwards.
6. For easy system bleeding and ushing, a
bypass non-return valve (6) is integrated in
the APP pump.
7. A non-return valve (7) in outlet can be
installed in order to avoid backspin of the
pump. The volume of water in the membrane vessel works as an accumulator and
will send ow backwards in case of the
pump stops momentarily.
8. A safety valve or a pressure relief valve (8)
can be installed in order to avoid system
damage as the Danfoss APP pump creates
pressure and ow immediately after startup, regardless of any counter pressure.
Note: If a non-return valve is mounted in the
inlet line, a low-pressure relief valve is also
required between non-return valve and pump
as protection against high-pressure peaks.
Media filter
PI
Feed
180R9405 | AN274337709031en-000302 | 11.2019
1
PI
1
PI PI
Fresh water
permeat flush
9 3
5
M
PT
2
7
4
6
PI
Brine
Permeate
PI
3
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