No Flow/No Pressure - Danfoss APP W HC Series Operation Manual

Service guide | Trouble shooting guide for APP, APP S and APP S 674 pumps
1.

No flow/no pressure

Cause
1.1 Dry running
(no water supply to the pump)
1.2 Pump reversing
(electric motor is running the wrong direction,
i .e . counter-clockwise)
1.3 No rotation of electric motor
1.4 No rotation of pump
1.5 Axial load on pump shaft
(may cause high internal leakage)
Only applying to
APP 0 .6 to APP 3 .5 and
APP 21 to APP 26 only .
Also applying to APP S and APP S 674 pumps .
1.6 Pump damage
(the internal parts may be damaged)
64 | © Danfoss | DCS (im) | 2022 .01
Remedy
If no water comes out of the pump:
1 . 1 . 1 Check that inlet valve is open .
1 . 1 .2 Check that booster pump is running .
1 .2 . 1 Change the phase on the electric motor to
make it run clockwise .
WARNING:
- The pump must not run without water for
more than a few seconds.
- If the pump takes in water from the high-
pressure outlet line, it builds up pressure in
pump housing and will eventually break
down.
1 .3 . 1 Check that main switch is switched on .
1 .3 .2 Check the electricity at the facility .
1 .3 .3 Ensure that motor relay is switched on .
1 .3 .4 Ensure that fuse is not blown .
1 .3 .5 Ensure that booster pump is started .
1 .3 .6 Check that the monitor switches are
working correctly .
1 .3 .7 Disconnect pump from electric motor and
check that the motor is capable of running
with no load .
1 .4 . 1 Ensure that coupling between electric
motor and pump is connected .
1 .4 .2 Check if coupling is damaged .
1 .4 .3 Check that electric motor is sized correctly .
1 .4 .4 Check that the electrical installation is
correctly sized .
1 .4 .5 Contact Danfoss Sales office for guidelines
in how to troubleshoot internal pump
parts .
1 .5 . 1 Ensure that the air gap between the two
coupling parts is min 5 mm . It should
always be possible to move the plastic part
on the coupling at least 3 mm .
1 .6 . 1 Contact Danfoss sales office for guidelines
in how to troubleshoot internal pump
parts .
180R9410 | AQ282628894589en-000801 | IOM APP W HC 15-30 Pumps
Comments
Mount a low pressure switch in front of the
pump and check its set point/ function . The low
pressure switch ensures that the pump does
not start until the inlet pressure has reached-
minimum inlet pressure (see User manual) .
Rotation direction for the APP, APP S or APP S 674
pump is shown by an arrow on the label on the
pump .
If motor-type relay or the electrical fuse is
blown, check that electric motor is sized
correctly .
To ensure easy mounting of the flexible
coupling without using tools, the tolerances
must be dimensioned accordingly .
WARNING:
Any axial and/or radial loads on the shaft
must be avoided. Any axial or radial load will
cause breakdown.
A - Bell housing
B - Flexible coupling
C - Motor shaft
A
Instructions on internal elements
are available on hpp .danfoss .com .
B C