40
180R9263 / IOM APP 5.1-10.2 Appendices - v02 / 01.2013
Instruction
Trouble shooting guide for APP pumps
6
Cause
Remedy
Comments
3.1 Too high outlet pressure from pump
3.1.1 Check fluid salinity.
3.1.2 Check temperature.
3.1.3 Check pressure drop across RO membrane.
Pump conditions may change (more salt, lower
water temperature or scaling of RO membrane)
causing higher pressure, resulting in higher
motor torque.
3.2 Pump starts against pressure
3.2.1 Check that electric motor is correctly sized.
3.2.2 Check internal parts (see item 2.1).
3.2.3 Systems with more than one electric
motor installed:
Start motors simultaneously.
Pumps run in parallel with cascade start, may
switch off the motor relay due to too high
torque caused by high outlet pressure.
3.3 Constant torque
3.3.1 Please contact Danfoss sales office.
If the electric motor is too small for the APP
pump it cannot provide sufficient torque.
3.4 Water pump damage
3.4.1 Dismantle pump and check for wear.
Too heavy damage in the pump will increase
friction causing a high torque (see item 6,
Typical signs of wear).
3.
High torque on electric motor
