Difficulty starting a Danfoss piston pump can have several causes, including: Insufficient or no fluid supply: If there is insufficient fluid in the system or if the pump suction line is clogged, the pump may have difficulty priming. In this case, the pump may hum, indicating that it is running but not pumping. Air in the system: Air pockets in the pump or system can cause pump priming difficulties. This can happen if the system is not vented properly, or if there is a leak in the suction line that allows air to enter the system. Motor or Power Problems: If the motor fails or the power supply is insufficient, the pump may have difficulty starting or not start at all. This condition can be caused by a variety of issues such as failed capacitors, burned motors, or loose connections. Water pump wear: Over time, the internal parts of the water pump can wear, causing the pump to have trouble starting. This can be caused by factors such as cavitation (the formation of air bubbles in the fluid due to high pressure) or erosion due to the abrasive nature of the pumped fluid. Improper installation: If the pump is not installed properly, it may start with difficulty or not at all. This can be caused by issues such as incorrect alignment, insufficient lubrication, or improperly tightened bolts. To diagnose the specific cause of Danfoss piston pump difficulty starting, it is recommended to consult the manufacturer's manual or seek the advice of a qualified technician. 90-L-100-KA-1-CD-80-S-3-F1-F-03-GBA-42-42-24 90L100KA1CD80S3F1F03GBA424224 90-L-100-KA-1-CD-80-S-3-S1-E-03-GBA-42-42-24 90L100KA1CD80S3S1E03GBA424224 90-L-100-KA-1-CD-80-S-4-F1-E-03-GBA-38-38-24 90L100KA1CD80S4F1E03GBA383824 90-L-100-KA-1-NN-60-L-3-S1-D-02-GBA-26-26-20 90L100KA1NN60L3S1D02GBA262620 90-L-100-KA-1-NN-60-L-3-S1-E-03-GBA-35-35-24 90L100KA1NN60L3S1E03GBA353524 90-L-100-KA-1-NN-60-P-3-F1-E-03-GBA-35-35-20 90L100KA1NN60P3F1E03GBA353520 90-L-100-KA-1-NN-60-P-3-F1-E-03-GBA-35-35-24 90L100KA1NN60P3F1E03GBA353524 90-L-100-KA-1-NN-60-P-3-F1-F-03-GBA-32-32-20 90L100KA1NN60P3F1F03GBA323220 90-L-100-KA-1-NN-60-P-3-F1-F-03-GBA-35-35-24 90L100KA1NN60P3F1F03GBA353524 90-L-100-KA-1-NN-60-P-3-S1-E-03-GBA-35-35-24 90L100KA1NN60P3S1E03GBA353524 Control valve failure: If the control valve is not working properly, it may cause the pump to have difficulty starting or stop working altogether. The control valve regulates the flow of fluid into the pump, so if it becomes stuck or not opened properly, it prevents the pump from operating properly. Contaminants in the fluid: Contaminants such as dirt or debris in the fluid being pumped can cause difficulty starting or malfunction of the pump. This can be prevented by using filters or screens in the system to remove contaminants before they reach the pump. Extreme Temperatures: If the pump is exposed to extreme temperatures, such as extreme cold or heat, it may cause difficulty starting or cause the pump to fail. This can be prevented by providing adequate insulation or ventilation to maintain a consistent operating temperature of the pump. Regular maintenance and inspection of Danfoss piston pumps is very important to prevent any starting difficulties or other problems. This includes checking fluid levels, checking for leaks, cleaning and replacing filters if necessary, and following proper installation and operating procedures. If the problem persists, it may be necessary to seek the advice of a professional technician to diagnose and repair the problem. Pump Cavitation: Cavitation occurs when low pressure exists in the pump suction line, causing air bubbles to form in the fluid. This may cause difficulty starting the pump or cause damage to pump components. To prevent cavitation, it is important to ensure that the pump has been properly primed and that the suction line is clear of any obstructions. Pump Seals and Gaskets: If the pump seals and gaskets are worn or damaged, it can cause difficulty starting the pump or cause the pump to leak. This can be prevented by regular inspection and replacement of any worn or damaged seals or gaskets. Electrical problems: Electrical problems such as a blown fuse, tripped circuit breaker, or faulty wiring can cause the pump to start with difficulty or not at all. It is very important to check the electrical components of the pump regularly and make sure they are working properly. Overload: If the water pump is overloaded, it will cause difficulty in starting or burn out the motor. This can be prevented by ensuring that the pump is not operating beyond its recommended capacity and is sized for the application. Damaged Pump Impeller: The impeller is the critical component of the pump and is responsible for creating fluid flow. Damaged, worn or corroded impellers can cause difficulty starting or reduced efficiency of the pump. This can be avoided by regularly inspecting the impeller for signs of wear or damage and replacing it if necessary. 90-L-100-KA-1-NN-60-P-3-S1-F-00-GBA-23-23-24 90L100KA1NN60P3S1F00GBA232324 90-L-100-KA-1-NN-60-P-3-T2-E-00-GBA-32-32-24 90L100KA1NN60P3T2E00GBA323224 90L100-KA-1-NN-60-R-3-C7-E-03-GBA-38-38-28 90L100KA1NN60R3C7E03GBA383828 90-L-100-KA-1-NN-60-R-3-C7-E-03-GBA-38-38-28 90L100KA1NN60R3C7E03GBA383828 90L100-KA-1-NN-60-R-3-F1-E-03-FAC-42-42-24 90L100KA1NN60R3F1E03FAC424224 90-L-100-KA-1-NN-60-R-3-F1-E-03-FAC-42-42-24 90L100KA1NN60R3F1E03FAC424224 90-L-100-KA-1-NN-60-R-3-F1-F-03-GBA-42-42-30 90L100KA1NN60R3F1F03GBA424230 90-L-100-KA-1-NN-60-R-3-S1-E-03-GBA-45-45-24 90L100KA1NN60R3S1E03GBA454524 90-L-100-KA-1-NN-60-R-3-S1-F-03-GBA-42-42-24 90L100KA1NN60R3S1F03GBA424224 90L100-KA-1-NN-60-R-3-S1-F-05-GBA-35-35-22 90L100KA1NN60R3S1F05GBA353522 Incorrect pump rotation: If the pump rotates in the wrong direction, it may cause difficulty starting or the pump not running at all. This can be caused by incorrect wiring or improper installation of the motor. To prevent this problem, be sure to follow the manufacturer's installation and wiring instructions. Pump Valve Failure: Pump valves regulate the flow of fluid within the pump and can wear out over time. If the valve is damaged or worn, it may cause the pump to start difficult or not run at all. Regular inspection and replacement of valves can help prevent this problem. Low voltage: If the voltage supplied to the pump is too low, it may cause difficulty starting or the pump not running at all. This can be caused by things like power failure or improper wiring. It is important to make sure the pump is receiving the correct voltage to run properly. In summary, there are several potential causes of Danfoss piston pump difficulties starting. Regular maintenance, inspection and replacement of worn or damaged parts can help prevent these problems and keep the pump running efficiently and reliably. If the problem persists, it may be necessary to seek advice from a professional technician or contact the manufacturer for further assistance.