Submersible pumps for draining

Some submersible pumps do their duty for years and are helpers in need, others fail after just a few hours of operation. We tell you, What to look out for when buying a submersible pump.

Full soakaways, We have often experienced flooded building pits or even flooded basements in recent years. Anyone who doesn't want to call the fire brigade immediately in the event of small floods, can tackle the water himself with his own submersible pump.

There are different types of submersible pumps. The most commonly used models are suitable for clear and only slightly polluted water. You should not use this to suck up sandy water or even sludge. Dirty water submersible pumps are built a little more robustly and suck in even small pebbles without damage.

Both submersible pump versions are designed to pump a lot of water, but provide little pressure. If you are looking for a submersible pump, to water the garden with water from the rain barrel or a cistern, you need a submersible pressure pump, which also produces the necessary pressure for the sprinklers.

Submersible pumps have a watertight motor housing. This consists of either plastic or stainless steel. Stainless steel has the advantage, that, unlike some plastics, the material does not deform when heated and is more resistant.

against aggressive liquids such as salt- or chlorine water. The top models of many manufacturers therefore have a stainless steel housing. But don't let the outside fool you, some cheap pumps with stainless steel housings only contain primitive technology.

seals
The design of the drive shaft and its sealing are decisive for the service life of the pump. The shaft should be made of high quality stainless steel. Prevent multiple ceramic mechanical seals, that water penetrates into the motor housing. Unfortunately, the design of the seal can only rarely be found in the manufacturer's brochures.

Pumpkin row
The open impeller of the pump can be made of plastic or metal. Impellers made of brass or stainless steel are considered to be very robust and durable, but can be easily damaged by small stones in the water. The softer plastic blades are more forgiving of such a stone chip. They don't bend or break easily.

float switch
Most submersible pumps today come with a float switch, who makes it possible, to operate them automatically in a seepage shaft, for example. Normally the float switch hangs down on a cable. The water level rises, the switch housing gradually floats up and switches on the pump from a certain position. The water level drops again, the floating switch housing goes back down and turns off the pump. For continuous operation, the float switch must be fixed in the on position for many pumps. Since the float switch is usually on a 20 cm long cable hangs, he needs space, to work properly. Should the submersible pump be housed in a narrow shaft?, a pump with an integrated float switch is recommended. Here the float switch is installed directly in the pump housing.

hose connection
Most submersible pumps today come with a screw thread and a universal connector with stages for multiple hose sizes. Choose the hose as large as possible and be sure to cut off the steps for smaller hose diameters, because every narrowing of the cross-section reduces the flow rate. It is also not recommended for the same reason, to use an adapter with a quick coupling system.

power cord
When buying a submersible pump, also pay attention to the length of the power cord. According to the regulations, it should be ten meters long. The manufacturer saves on the power cord, so the highest quality parts are not to be expected inside the pump either.

flow rate
To choose the right pump, you should look at the performance data.

Decisive
is not the motor power in watts, but the flow rate and the maximum head are the interesting data. installed between the half-height cupboards, that the manufacturers use different units of measurement for the flow rate. To compare different pumps, you have to convert the information to the same unit. The flow rate in liters per hour is given most frequently. numbers like 10 000 l/h sounds huge, but what does that actually mean? Assumed, You have a basement with you 30 square meters of floor space, the 1 m is under water. That's a volume of 30 000 l. A pump with a capacity of 10000 l/h would have to run for three hours, until the basement is drained, provided, the head is equal to zero. at 3 m head, the hourly output is only 5800 l, the pump would then have to run for five hours and ten minutes.

head
Flow rate and head are performance characteristics, that depend on each other. Every centimetre, which the submersible pump has to transport the water upwards, reduces the flow rate. The maximum flow rate always applies to a head of 0 cm. With increasing delivery head, the delivery rate decreases. Until they are practically only at the maximum delivery head 0 l/Min. amounts to. As a rule, the flow rate for different delivery heads is shown as a performance diagram on the pump packaging. Choose the pump like this, that it can handle the volume of water to be transported in an acceptable time. A submersible pump, which needs three days of continuous operation, to empty the swimming pool, is definitely undersized. When pumping dirty water, refer to the for each pump-
pe specified grain size. Clear water pumps are usually only suitable for grain sizes of a few millimeters. finest clay- or sand particles do not damage most pumps, however, small stones can damage or jam the pump impeller, causing the motor to burn out. Depending on the manufacturer and model, submersible pumps for dirty water have a maximum particle size of approx 25 to 40 mm laid out. The impeller has more air for this purpose, to turn over sand and small stones.

A special feature are submersible pumps, which can suck off the water almost completely. Sometimes only small puddles remain, which can be wiped up easily. However, since the larger ones are affected when the water is dirty, deposit heavier particles on the ground, In this case, you should not set the pump to suction down to a residual water level of a few millimeters or, even better, set the pump a little higher, for example on a stone, place, to prevent, that dirt particles that are too large are sucked in.