How to Adjust a Tethered Sump Pump

Tether Length

• One way to adjust a tethered sump pump is by lengthening or shortening the tether. This will affect the point at which the metal bead inside the switch causes the pump to run, since the length of the tether controls the angle of the float as it rises. If the tether is too long, the pump won't engage when the water level is high. A tether that is too short will cause the pump to run even when the water level is relatively low.

Tether Position

• The position of a tethered sump pump's float is another point of adjustment for keeping the pump running properly. If the tether needs to be longer to keep the pump from coming on too early, the float may become entangled in the pump mechanism or the sides of the sump well, preventing it from rising as it should. Placing the tether in a location where its length makes it difficult for it to catch on anything will allow the pump to turn off and on automatically based only on the water level.

Internal Adjustment

• Adjusting the metal bead inside a tethered sump pump's float is a more complex type of adjustment. The bead is usually made or mercury or steel; if it's a mercury bead, you should avoid opening the float, since exposure to mercury can be harmful. With a steel bead, you can open the float to clean the electrical contacts. Replacing an old mercury float with a steel float is a good option for ensuring that your sump pump doesn't contain hazardous materials, though you'll need to ensure that you dispose of the mercury float properly so that it doesn't contaminate the environment.

Water Level

• To test a tethered sump pump switch, you may need to adjust the water level by manually adding water to the sump well. You can do this by pouring water into the well or running a hose from outside into your basement. The water level will fall automatically once the pump begins to run. However, the rate at which the pump discharges water should determine the water level you select as an appropriate level for the pump to engage, based on other adjustments of the tethered switch.