Sump pumps are designed to pump out water from the lowest section of your basement. The goal is for the pump to move the water away from your foundation before the water reaches the basement floor level. If your sump pump ceases to function properly, you may not know it until you really need it to work. Many manufacturers recommend that, in order to make sure the sump pump is functioning properly, you have it run or tested every two to three months.
Check the strainer and inlet valve if your pump is not delivering enough water. They may be clogged. Also, see if your suction line or the fittings are leaking air. See if the mechanical seal is worn. It could be leaking air or water. You may also have a problem with the suction lift being too high. If the lift is 25 feet, it will only deliver approximately 50 percent of the water that it can deliver if the lift is only 10 feet. In addition, the suction hose may be too long. If it is, it may cause excessive friction loss and will cause a reduction in pump capacity.
Check to see if the mechanical seal is leaking if the pump is not delivering enough pressure. In addition, the engine may not be performing at its rated speed. Refer to your model's owner manual for the appropriate speed for your machine. You may also have too much clearance between the pump body (or volute) and the impeller. This can be caused by excessive wear. Refer to your owner's manual for how to adjust this clearance.
Make sure, if the sump pump does not prime properly, that the pump casing is filled with water. Also check to see that all the suction line fittings are tight and that the hose is not leaking. See if the inlet valve rubber is frozen to the seal. Check to see if the pump is not running quickly enough. In addition, if the water is too warm, the pump may have difficulty priming. You may need to replace the water with fresh water, generally under 60 degrees F.
Check to see if you have a defective float switch if the pump won't shut off. You may also have an obstruction in the piping which is restricting the discharge. If this is the case, remove the pump and clean it and the piping. If the float is blocked in some way, remove the obstruction.
Install or replace the check-valve if the pump starts and stops too often. You may have a backflow of water from the piping. If this does not solve your problem, the issues may be a faulty float switch, in which case, it will need to be replaced.
