Checking the washing machine drain pump with a multimeter

Checking the washing machine drain pump with a multimeter There are different reasons why the washing machine stops draining water. Usually the pump is the culprit. Let's figure out how to check the pump of a washing machine with a multimeter. You can perform diagnostics yourself, at home, without calling a specialist.

How to quickly get to the pump?

It is quite possible to check the SMA drainage pump on your own. First you need to make sure that the pump impeller rotates freely. Sometimes it becomes blocked by debris, threads and hair wrapped around the blades.

To check the drain pump impeller, you need to:

turn off the power to the washing machine by unplugging the power cord from the outlet;
turn off the shut-off valve responsible for supplying water to the machine;
disconnect the drain and inlet hoses from the SMA;
remove the lower false panel or open a special hatch (behind it there is a SMA garbage filter);
place a low container under the body of the machine, in the area where the drain filter is located (after removing the plug, water that has accumulated in the pipes may pour out of it);
unscrew the “trash can” plug;
collect the water that flows from the hole into a prepared container;
illuminate the opened hole, remove debris if there is any;
turn the pump impeller with your fingers or a stick - the part should move freely.

If the impeller movement is difficult, check to see if there is a foreign object stuck between the blades, or if there is hair, thread or other debris wrapped around the part.

If everything is visually in order with the impeller, it is recommended to test the SMA drain pump with a multimeter. To diagnose the pump with a tester, you will have to get closer to it.The further algorithm of actions is as follows:

cover the floor with a blanket;
lay the automatic machine on its side, on the backing;
remove the CMA pan, if provided;
look under the base, find the pump and snail.

To perform a function test, it is not necessary to remove the drain pump. You can leave the part in the SMA body. We'll tell you how to proceed next.

Is the pump winding intact?

Next, you need to ring the pump with a multimeter. The normal resistance of the stator winding of the drain pump of an automatic machine is 150-250 Ohms. If the tester display shows a value within this limit, it means that the winding of the part is intact.

Before testing the pump with a multimeter, make sure that the washing machine is de-energized.

Switch the tester to ohmmeter mode. Next, disconnect the power cables from the drain pump. After this, attach the multimeter probes to the terminals and evaluate the values on the device screen. checking the drain pump with a multimeter

A slight deviation from standard values, plus/minus 10 ohms, is acceptable. A zero or one on the multimeter screen will indicate a short circuit in the circuit. An infinite number indicates damage to the stator winding. In such cases, the drain pump cannot be repaired; a complete replacement of the pump will be required.

If the readings on the multimeter are normal, check to see if the pump volute is clogged. To do this, disassemble the body of the part. Sometimes debris that gets inside the pump interferes with its operation. In this case, it will be enough to clean the element.

We connect the pump directly to 220 V

The multimeter only shows the integrity of the drain pump winding. However, it happens that the impeller jams due to wear on the bushings, and when you unscrew it with your finger, this cannot be noticed. Therefore, there is another, more reliable way to check the pump’s performance.

To do this, you need to connect the pump directly to the outlet, bypassing the electrical circuit of the washing machine. In this case, you don’t even have to pull the part out of the washing machine body. The algorithm of actions will be as follows:

turn off the power to the automatic machine;
get to the drain pump (how to do this is described in detail in the previous paragraphs);
disconnect the power supply from the pump coil;
prepare a power cord with a plug at one end and two wires with terminals at the other;

For better protection, it is recommended to install a fuse in the power cord gap.

insert the power cord terminals into the drain pump connectors;
plug the cord into a 220 volt outlet.

After connecting the drain pump to the power supply, the impeller should begin to rotate. If it clicks and stays still, then the pump is faulty. It is likely that the rotor body touches the stator, causing the blades to jam. In this case, the element will need to be replaced.

You need to purchase a new drain pump, looking at the model and serial number of the automatic machine. The ideal option is to dismantle the broken pump and take it to the store. Then the seller will select a similar spare part.

The new pump is placed in place of the old one and secured with bolts. Next, the power wires are connected to the pump contacts. After this, the machine body is assembled and the test cycle starts.