Danfoss PAH 2 - Trouble Shooting Fish Bone Chart

Guideline Trouble shooting guide for PAH, PAHT, PAHT C , PAHT G pumps
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180R9379 | AQ188686503004en-000801 | PAH 2-12.5 } 07.2022
Trouble shooting
sh bone chart
1. No ow/pressure
3. High torque on el. motor
4. Noise from pump
5. Noise from installation
2. Reduced ow/pressure
1.1 Dry running
1.2 Pump reversing
1.3 No rotation of electric motor
1.4 No rotation of pump
1.5 Axial force on pump shaft
1.6 Pump damage
2.1.5 Pre-treatment
2.1.6 Main ltration
2.1 Wear in pump
(internal leakage)
2.1.7 Type of uid
2.1.8 High uid temperature
4.1 Air in uid
4.2 Bleeding conditions of pump
4.3 Min/max nominal
inlet pressure
4.4 Pump reversing
4.5 High rotation speed (RPM)
4.6 Outlet pressure
5.1 Inlet/outlet connections
(hoses/pipes)
5.2 Length/dimensions of
inlet/outlet line
5.3 Hose stiness
5.4 Hoses/pipes mounted
directly on frame
5.5 Vibration damper under the
electric motor
3.1 Too high outlet pressure
from pump
3.3 Constant torque
3.4 Water pump damage
4.7 Soft start/stop
PUMP FAILED
3.2 Pump starts against pressure
2.2 Low inlet pressure
2.3 RPM