Reversible Pumps; General Comments; Building Up The Pump Unit; Mounting - Danfoss APP W HC Series Operation Manual

Instruction | APP W HC 15-30 pumps
3. Building up the
pump unit
3-5 mm
0.12-0.20 inch
D
36

2.3 Reversible pumps

If exposed to high-pressure in the outlet while
the electric motor is not energized, the pumps
will start spinning backwards . This will not harm
the pumps as long as the pressure in the inlet
does not exceed the max . pressure peak of
10 barg (145 psig) .
If a non-return valve is mounted in the inlet line,
a low-pressure relief valve is also required as
protection against high-pressure pulses and
high-pressure in general .
Alternatively a high-pressure check valve can be
mounted in the pump discharge line to prevent
the pump from reversing .
The dotted setup ensures that the inlet pressure
does not exceed 10 barg (145 psig), when a non-
return valve is mounted in the inlet .
In order to avoid the risk of cavitation, the
inlet pressure for APP W HC 15-30 must be min.
2 barg (29 psig).
The inlet line connection must be properly
tightened, as possible entrance of air will cause
cavitation .

2.4 General comments

Filtration
A good filtration is vital to ensure a long and
trouble-free life of the pump.

3.1 Mounting

1 . Mount the coupling flush or maximum
1 mm offset from the pump shaft end .
Ensure an air gap between coupling parts
of 3-5 mm (0 . 1 2-0 .2 inch) .
2 . Mount the bell housing on pump . Secure
nuts with the right torque .
3 . Measure the longest distance "A" from top
of bell housing to the button of coupling
claw .
180R9410 | AQ282628894589en-000801 | IOM APP W HC 15-30 Pumps | 01.2022
As water has very low viscosity, the APP W HC
pumps have been designed with very narrow
clearance in order to control internal leakage
rates and improve component performance .
Therefore it is important that the inlet water is
filtered properly to minimize the wear of the
pump .
The main filter must have a filtration efficiency of
99 . 9 8% at 10 μm . We recommend to use
precision depth filter cartridges rated 10 μm abs .
β10 ≥ 5000 (equivalent to a filtration efficiency of
99 . 9 8%) . Bag filters and string wounded filter
cartridges typically have only 50% filtration
efficiency . This means that for each 100,000 parti-
cles reaching the filter, 50,000 particles pass
through it compared to only 20 particles in a
filter with an efficiency of 99 . 9 8% .
For more information on the importance of
proper filtration, please consult our publication
"Filtration" (code number 521B1009), which also
will provide you with an explanation of filtration
definitions and a guidance on how to select the
right filter .
Monitoring
It is recommended to continuously monitor the
following conditions:
• Filter clogging
• Pressure (inlet- and outlet side of the
pump)
A: Elastic coupling
B: Bell housing
C: Motor shaft
D: Pump flange
4 . Mount the coupling on motor shaft . Ensure
the coupling and motor flange are not in
contact with each other .
5 . Measure from motor flange to the top of
the coupling . That measurement "B" shall
be 3-5 mm (0 . 1 2-0 .2 inch) shorter than the
measurement "A" .
("A" and "B" can be found on the next
page) .