FAQ - Pumps, Motors & Self-Priming

With over 150 years of combined professional experience the Dade Pump & Supply Co DBA De Ruiter Electric Motor Company has the knowledge you need to assist with your pump, motor and overall system questions or issues. Below are a few we run into frequently that may be of assistance. If you don't see the question you have feel free to reach out to info@dadepump.com or call our team at 305-235-5000. 

How high can I lift water with my pump?

Although commonly referred to as a suction lift, pumps do not actually lift liquid. They create a vacuum by evacuating the air in the line, and atmospheric pressure on the liquid pushes it up the pipe/hose and into the pump. The rule of thumb for most self-priming pumps is a maximum 25' vertical suction lift. Before operation, we recommend checking your manual or with our technical team at Dade Pump if you are unsure of your pump's capabilities. That said; it is always best to locate your pump as close to the liquid being pumped as possible. **Note: Not all pumps are self-priming.

I just finished installing my self-priming pump but it isn't working. What did I do wrong?

Self-priming pumps require priming the first time they are used. You can gravity or force feed liquid into the pump to "jump" start the flow. A self-priming pump is built with a large pump housing and an inlet above the eye of the impeller. This design allows water to stay in the head after the pump is stopped which will give the pump the water it requires to prime. The misconception is that the pump will always prime and it does not need a check valve. This is only true in perfect conditions which are seldom ever present. We recommend priming your pump and using a check valve when possible.

I have a home water system. How much pressure (psi) should my pressurized tank have in it?

The general rule of thumb is 2-4 PSI less than your cut on pressure set on your Pressure Switch. Example 1: Pressure Switch Setting: 20/40 Tank Pressure: 16-18 PSI, Example 2: Pressure Switch Setting: 30/50 Tank Pressure: 26-28 PSI, Example 3: Pressure Switch Setting: 40/60 Tank Pressure: 36-38 PSI, **Note: To get an accurate reading of the pressure in your tank, the tank must be empty (no water).

Why won't my jet pump shut off?

Cause:  Debris from the well may have clogged your pump's jet package not allowing the pump to build sufficient pressure for the pressure switch to reach its set shut off pressure and allow the pump/motor to turn off.

Solution: Jet package needs to be unclogged. There are different methods depending on your particular pumps design. Please contact us for further assistance if needed. If possible please have the make and model of your pump handy.

Cause: Hose from pump body to pressure switch is blocked / clogged / frozen or has come off one end.

Solution: Relieve pressure from system. Remove hose from pump body and pressure switch and see if you can blow through it. If clogged, remove whatever is clogging it. Reinstall hose.

Why does my pump sound like it is pumping gravel or rocks?

This is likely caused by cavitation. Cavitation is the formation of vapor cavities in a liquid i.e. small liquid-free zones ("bubbles" or "voids") that are the consequence of forces acting upon the liquid. It usually occurs when a liquid is subjected to rapid changes of pressure that cause the formation of cavities where the pressure is relatively low. When subjected to higher pressure, the voids implode and can generate an intense shockwave. Symptoms of cavitation include excessive noise and vibration and loss of capacity, pressure and efficiency. Cavitation can cause damage to the pump. Solutions include changing the operational parameters or even replacing your pump with a pump that may be better suited to the application.

My pump continuously starts and stops. Will this harm the motor?

YES, this is very damaging to the motor. Every time the motor starts, the windings see a high inrush current of up to about 10 times the nameplate amps (locked rotor code M). The motor dissipates the inrush of energy as heat. If you start the motor too many times, a buildup of heat can cause damage to the motor.

Why won't my pump prime?

The majority of the time we find the pump is not being fed properly - blockage or drawing air - or there is a Net Positive Suction Head (NPSH) issue related to the temperature or type of fluid (viscosity, etc). Unless the pump you have is a self-priming pump, it will not prime unless the pump is full of water and there is no air trapped inside locking the pump. Suction leaks that cause a break in vacuum issues with the suction pipe (pipe that runs from well to pump) are very common in all industries we work with. If there is not a suction issue or NPSH issue the mechanical seal may have failed in the pump causing a break in vacuum.

Will a Centrifugal Pump work if it is running backwards in the reverse rotation it is intended to?

Yes it will run, but not as it should. If the motor and pump are running backwards, the pump can often still move water, and the water will flow the normal direction through the pump but at a far slower rate than normal operation. A centrifugal pump accelerates water off of the tips of the impeller vanes. When an impeller is running backward, the centrifugal forces will still accelerate the wateralthough far less efficiently. A backward running pump will deliver less water, at a lower pressure and will typically consume less electricity. If the impeller is threaded to the shaft, it may unscrew when running backwards. This will also most likely void the manufacturer's warranty during their evaluation process.

If I increase the HP of the motor running my pump will it increase performance?

No, in 95% of cases. The performance of the pump is based on the diameter and vane width of the impeller, the rotational speed of the motor as well as the horsepower is defined to the point more HP will not yield more flow or pressure.