Guide line | Trouble shooting guide for PAH, PAHT, PAHT C , PAHT G, PAHT 674 and PAH F pumps
63
180R9316 | AQ176586503002en-000501 | IOM PAHT C 2-6.3 pumps | 01.2022
4.
Noise from pump
Cause
Remedy
Comments
4.1 Air in fluid
4 .1 .1 Ensure that the entire inlet line is bled
before starting up the system .
4 .1 .2 Ensure that air cannot enter into the inlet
line .
Small air bubbles will accumulate and create
large bubbles causing internal cavitation and
thus making the pump very noisy .
WARNING:
The pump can only run few minutes with air in
the fluid without being damaged.
4.2 Bleeding conditions of pump
4 .2 .1 Follow the instructions “Initial start-up”
supplied with the new pump .
4 .2 .2 Ensure that the pump is completely bled
before start-up .
The pump and the inlet line must be completely
bled before start-up, otherwise the pump will
cavitate and make high noise .
WARNING:
The pump can only run few minutes with air in
the fluid without being damaged.
4.3 Min/max nominal inlet pressure
4 .3 .1 Ensure that inlet pressure is within
the limits specified in the Data sheet .
4 .3 .2 Check the pump for internal damage .
Too high inlet pressure causes too high pressure
inside the pump damaging the pistons and
eventually the pump .
Inlet pressure below min . limit causes cavitation
and insufficient internal lubrication resulting in
wear on internal pump parts .
Mount a low-pressure switch in front of the
pump and check its set point/ function . The
low-pressure switch will ensure that the pump
does not start until the minimum inlet pressure
has been reached .
4.4 Pump reversing
4 .4 .1 Dismantle pump and check if anything is
broken or worn (See “1 . No flow”, item 1 .2
Pump reversing”) .
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 and will
eventually be damaged.
If pump rotates in wrong direction, it will take in
water from the high-pressure outlet line .
Pressure will be built up inside the pump and it
will eventually be damaged .
4.5 High rotation speed (rpm)
4 .5 .1 If electric motor rpm is too high, dismantle
pump and check for damage .
4 .5 .2 If the rpm is within the specified range of
the pump data sheet and abnormal noise
remains, dismantle pump and check for
damage .
Higher rpm than specified in the pump data
sheet results in wear of the pistons, i .e . pistons
may be damaged .
High rpm will also increase pressure pulsations
from the pump, and the noise level will increase .
If rpm is changed, noise frequency will also
change .
4.6 Outlet pressure
4 .6 .1 If outlet pressure is too low, check set point
of outlet pressure valve .
4 .6 .2 If outlet pressure is lower than mentioned
in the pump data sheet, please contact
Danfoss High Pressure Pumps technical
support .
4 .6 .3 If outlet pressure has exceeded its
maximum, check set point of outlet
pressure valve .
4 .6 .4 Check internal parts for wear/damage .
At too low outlet pressure, the pump will create
higher pressure pulsations and thus make noise .
Too low pressure also causes insufficient internal
lubrication and wear on internal parts . Pump
may eventually be damaged .
Too high outlet pressure may damage the pump .
4.7 Soft start/stop
4 .7 .1 Check if noise is normal when the pump is
running at operation speed .
4 .7 .2 If noise is abnormal at operation speed,
check internal parts (see above) .
Noise frequency changes during soft start-up/
stop .
Summary of Contents for PAHT C
Page 30: ...Danfoss DCS im 2017 06 521B1374 A 234386502982en000401 PAHT C pumps UK 06 2017 30...
Page 46: ...46 180R9316 AQ176586503002en 000501 IOM PAHT C 2 6 3 pumps 01 2022...
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