Understanding Sump Pump Switches

If you are searching for “sump pump switches” or “sump pump float switch types” this post should help! The primary connection that controls the sump pump is the sump pump switch, and damaged or defective switches are often the main reason of malfunctioning sump pumps; without a working switch, the pump won’t turn on. You can get vertical, tethered, diaphragm, and electrical switches in the market, each one ideal for a specific type of installation. We’ll tell you more about them so you can decide which one is the best for your needs.

Knowing what kind of switch you need is essential, but even more important is having it installed correctly. Below we have outlined the considerations and things you should and shouldn’t be doing when installing a sump pump switch.

To piggyback or not?

A piggyback plug is one with two cords, as opposed to a single cord. A single cord plug will most likely be an internally wired vertical switch which is permanently attached to the pump.

Piggyback plugs let you conveniently test the pump. Of the two cords, the one with only the male plug goes in the sump pump while the one with both the male and female plugs is the switch.

You can test the pump by unplugging the pump cord from the switch cord and plugging it in directly into the main outlet. The pump is operational if it turns on.

Why is a properly installed switch necessary?

Proper installation of the switch is vital to ensure your pump remains operational and your basement is protected. With a variety of switches in the market, you’ll find some that are adjustable, and some that aren’t and choosing the right one for your pump is essential. If your pump doesn’t cycle properly, for instance, if it often runs for a short cycle, this can unduly stress the pump.

When the pump runs under water, the water acts as a cooling agent to prevent the pump from heating up excessively, as excessive heating will shorten a pump’s lifespan. For this reason, most sump pumps also come with a thermal overload switch.

Vertical Switches

Vertical switches make use of a piggyback plug, can be easily installed and are adjustable, making them suitable for most common installations. The switch comprises of a float, a rod, and a switch encased in a small housing that attaches to the discharge pipe or the body of the pump.

The operation of a vertical switch is relatively straightforward. As the water level in the sump basin rises, the float rises with it, and the switch is activated it reaches a particular height, turning the pump on. When the water level falls, the float crosses the predetermined height, and the switch is flipped, turning the pump off.

Vertical switches are ideal for small diameter basins that aren’t very deep. Since the switch travels on a rod that is attached to the pump or discharge pipe, its motion is somewhat controlled and doesn’t vary a lot. The cycle length of the float switch is determined by the length of the sensor rod.

Diaphragm Switches

The Diaphragm switch also utilizes a piggyback plug and are great for some installations. Unlike most other sump switches, diaphragm switches are activated by pressure. For this reason, they are attached very low on the side or the body of the pump.

The pressure on the switch increases as the water level in the sump basin rises, and when the pressure increases enough to compress the bladder in the switch, it activates, turning the pump on. When the water level falls, the pressure on the bladder is reduced allowing it to re-expand, de-energizing the switch and turning the pump off.

They are ideal for sump basins that don’t have a lot of room and are congested. These types of switches are great for basins with very little room or basins that are congested. A disadvantage of diaphragm switches is their lack of adjustability, so it’s crucial you purchase the correct switch.

The Tethered Switch

The tethered switch can either be internally wired or piggybacked and is commonly used because of its simple operation. The switch mechanism comprises of spherical float, holding a steel ball or mercury inside, attached to the pump or the basin lid with a cord. Mercury switches are more economical but are falling out of fashion because of their adverse impact on the environment.

In case of the switch being hung from the basin lid, a weight is connected to the setup so that the cord can pivot. In both installations, however, the operation remains the same.

As the water level rises and the float extends the cord, it starts to pivot. The switch that is floating in the water continues to float and pivots straight up, forcing the mercury or the steel ball inside to sink to the bottom and energize the switch. As the water level falls, the cord extends down resulting in the ball or the mercury sinking to the other of the switch, turning the pump off.

A drawback is that tethered switches require a lot of space and can only be installed in a wide basin to avoid the float from getting stuck on the pump or the side of the basin. They are adjustable but the more the cord is adjusted and left out, the more likely it is for it to get tangled on things inside the basin.

In domestic installations, the switch is more likely to be attached to the while commercial applications make use of switches hung from the basin lid.

Electronic Switches

There is a variety of electronic float switches on the market, and most of them are relatively new introductions, not older than five years. The most significant advantage they have over other switches is that they comprise of minimal to no moving parts.

One particular kind of electronic switch employs a probe attached at the level you want the pump to turn on. The run time can be adjusted or preset via the control box.

Another kind of electronic switch uses a single or two floats traveling inside a caged enclave. An installed sensor determines the location of the float and turns the pump off and on accordingly. Run times can be controlled via the control box mounted on the outside.

Electrical switches are becoming a popular choice because of two main reasons. The first is the location of the control box. Since the control box is affixed on the outside and not submerged within the basin, there’s less wear and tear, and its lifespan is prolonged. The other reason is the lack of moving parts; the more moving parts there are, the more the chances are that something may go wrong.

Determining the Type of Float Switch for Your Sump Pump

As we’ve detailed earlier, there are several kinds of switches, so it’s essential to determine the type of switch installed on your pump when purchasing a replacement. Preferably with the help of a digital voltage meter, and determine whether power is present at the outlet. You can also use small electronics like a lamp to check for power.

Once you’ve confirmed that power is present, you will need to open up the basin. Depending on your sump pump, the lid on top will either be sealed, unsealed, or bolted down. If you have a radon mitigation system installed in your home, it is essential that you close and seal the cover just the way it was when you’re done.

When the cover has been removed, and the switch has been located and identified, you can go ahead with the testing. Testing a tether switch is simple; hold the float in a position that the wire is facing down, making sure that the tether doesn’t entangle with the side of the basin or other cords. If this action turns the pump on it means the switch mechanism is operational, as long as the pump turns off when the float is released, and the cord is facing up.

When testing the vertical switch, locate the float, then lift it upwards until it is unable to travel any further. If the pump energizes due to this and turns off when the float is released, it shows that the switch is operational.

You can test electronic switches in a similar manner. Using a coat hanger, a screwdriver or any other insulating equipment, move the float upwards and note if the pump turns on.

This last test can be employed to test any switch but is particularly useful when testing pressure and electronic sensor switches. Start by identifying and blocking the sump pit inlets with either a test plug or a big towel. When they’ve been plugged, use a bucket or hose to fill the pit with water, and observe if the pump cycles. If the pump turns on it’s excellent, as long as it also turns off or else it will burn up.

If neither of these tests was successful in turning your pump on and you have a piggyback switch, you have one more option to turn the pump on. Start by separating the male pump plug and the piggyback switch plug, plugging the male plug directly into the outlet. This should ideally turn your pump on. This method can be employed in emergencies when the switch isn’t operational; however, remember to proper precautions since you are dealing with electricity.

Replacing a Sump Pump Switch

The simplest way to go about this is to identify the type of switch your pump uses and get the same one from the market. You should note that if your switch is internally wired, it is non-replaceable and will have to be returned to the manufacturer.

If you would like to replace your current switch with another type of switch, this is how you can do it. Ensure that all plugs have been unplugged, or disconnect the pump and take it off the basin before proceeding.

To proceed with the removal, identify the check valve. The check valve is usually connected with hose clamps, and bottom clamps also called union halves. The union halves are the only clamps that you will need to loosen. Loosening the upper clamps will release all the water in the valve on your face.

Once the check valve has been disconnected from the piping, the pump can be removed. While doing this, ensure that the wires don’t catch on to anything. When this is done, and the pump is removed, you can remove the current switch and install the new one.

Always remember to install the switch the correct way. If unsure, refer to the instructions provided by the manufacturer. When the replacement procedure is complete, ensure the wiring is secure to prevent interference with the switch’s operation.