Q: Where is the water tank located on the Nilfisk CA 551 scrubber?

The Nilfisk CA 551 scrubber has two distinct tanks: Solution tank (16) : intended for cleaning water with detergent, with a capacity of 58 liters Recovery water tank (17) : collects dirty water after suction, with a capacity of 60 liters Filling the solution tank The tank is filled using the chute (5). Pour in a suitable solution for the task at hand, without filling completely - leave a few centimeters from the edge. The hose (13) at the back serves as a level reference. The water temperature must not exceed 40°C. Important: use only low-foaming, non-flammable liquid detergents. Emptying the tank After use, empty the tank via the flexible hose (13) located at the back of the machine, then rinse it with clean water.

Q: The machine does not move at the set speed

First, check that the speed regulator is properly set . On the BA 651, the traction speed ranges from 0 to 5.6 km/h and depends entirely on the regulator (84). Turn this regulator counterclockwise to increase the maximum allowed speed, and clockwise to decrease it. Check the control lever (83) . For the machine to reach its set maximum speed, you must push the lever all the way forward (to move forward) or backward (to reverse). A partial push will limit the actual speed, even if the regulator allows the maximum speed of 5.6 km/h. Check the battery status . If the green indicator (81a) is not lit, the batteries are partially or completely discharged. In this case, the machine cannot reach its maximum speed. Charge the batteries to restore optimal traction power. The traction motor consumes a lot of energy, and weak batteries directly reduce performance. Check the operating conditions . The machine can climb a maximum slope of 2%. On an inclined surface, the forward speed will be slower than on flat ground. Additionally, if the recovery water tank (85 liters) is full or if you are carrying an additional load, the traction motor (200W) may not provide the maximum speed. If the traction motor is not functioning normally , consult an authorized NILFISK repair service. Check for any abnormal noise and ensure that the motor responds to commands. An electrical issue with the traction motor will require the intervention of a qualified technician.

Question 1

Where is the water tank located on the Nilfisk CA 551 scrubber?

Accepted Answer

The Nilfisk CA 551 scrubber has two distinct tanks:

Solution tank (16): intended for cleaning water with detergent, with a capacity of 58 liters
Recovery water tank (17): collects dirty water after suction, with a capacity of 60 liters

Filling the solution tank

The tank is filled using the chute (5). Pour in a suitable solution for the task at hand, without filling completely - leave a few centimeters from the edge. The hose (13) at the back serves as a level reference. The water temperature must not exceed 40°C.

Important: use only low-foaming, non-flammable liquid detergents.

Emptying the tank

After use, empty the tank via the flexible hose (13) located at the back of the machine, then rinse it with clean water.

Question 2

The machine does not move at the set speed

Accepted Answer

First, check that the speed regulator is properly set. On the BA 651, the traction speed ranges from 0 to 5.6 km/h and depends entirely on the regulator (84). Turn this regulator counterclockwise to increase the maximum allowed speed, and clockwise to decrease it.

Check the control lever (83). For the machine to reach its set maximum speed, you must push the lever all the way forward (to move forward) or backward (to reverse). A partial push will limit the actual speed, even if the regulator allows the maximum speed of 5.6 km/h.

Check the battery status. If the green indicator (81a) is not lit, the batteries are partially or completely discharged. In this case, the machine cannot reach its maximum speed. Charge the batteries to restore optimal traction power. The traction motor consumes a lot of energy, and weak batteries directly reduce performance.

Check the operating conditions. The machine can climb a maximum slope of 2%. On an inclined surface, the forward speed will be slower than on flat ground. Additionally, if the recovery water tank (85 liters) is full or if you are carrying an additional load, the traction motor (200W) may not provide the maximum speed.

If the traction motor is not functioning normally, consult an authorized NILFISK repair service. Check for any abnormal noise and ensure that the motor responds to commands. An electrical issue with the traction motor will require the intervention of a qualified technician.

Question 3

How does the device detect the insertion of a brush or accessory?

Accepted Answer

The NILFISK SB TANDEM uses a mechanical switch detection system. When you insert the brush or accessory into the designated compartment, it activates an internal detection switch that recognizes the presence of the equipment.

This recognition mechanism generally relies on:

A mechanical switch physically activated by the insertion of the accessory
An electrical signal transmitted to the control board to validate that the accessory is correctly in place
A safety validation before the system starts

Note: The PDF of this manual does not detail the operation of the sensor precisely. If you need to know the exact location of the switch or additional technical details, check the maintenance and assembly section of the full manual or inspect the insertion compartment.

Question 4

The machine does not start despite the presence of voltage on the electronic board - what should I do?

Accepted Answer

If the NILFISK SB TANDEM does not start while voltage is present at the electronic board, the problem is likely due to a faulty or dirty component in the control system. Follow this step-by-step diagnostic procedure.

Step 1: Check the coin tester
The coin tester is the first element to check. It may be dirty or faulty and prevent the machine from starting even if the voltage is good. Clean the coin slot with a cloth soaked in white spirit, making repeated passes. If cleaning does not improve anything, the tester may be faulty and needs to be replaced.

Step 2: Manually test the suction turbine
On the SB TANDEM, the test button located on the timer circuit (visible after opening the coin tester cover) should trigger the turbine to start for a few seconds. Press this button: if the suction turbine starts, then the coin tester is the problem. If it does not start, then the turbine, the push button, or the timer is faulty.

Step 3: Check the turbine connections
Make sure all electrical connectors linking the suction turbine to the control board are properly plugged in and not corroded. Unplug and then firmly reconnect each connector.

Step 4: Inspect the control relay
The relay that controls the turbine may be stuck or faulty. If you have electrical knowledge, refer to the wiring diagram in the manual to check that this relay is receiving voltage from the coin tester.

If after these checks the machine still does not start, one of the following components is faulty and needs to be replaced: coin tester, suction turbine, control relay, or timer. In this case, contact ALTO customer service or an authorized workshop.

Question 5

My NILFISK MH 4M pressure washer won't start - should I check the fuses or circuit breakers?

Accepted Answer

The NILFISK MH 4M does not have internal fuses in the traditional sense. However, several points should be checked before concluding an electrical failure:

Electrical Checks

Breaker in your home installation: Check that the breaker in your electrical panel has not tripped. If it has, reset the breaker.
Power cable: Thoroughly inspect the power cord for damage, cuts, or wear that could prevent the device from receiving power.
Voltage of your installation: The MH 4M operates at 230V or 400V depending on the models. Ensure that the available voltage matches your installation.

Other common causes of non-starting

Before concluding an electrical fault, note that the MH 4M has a safety feature that prevents starting without water flow. Therefore, check:

That the water inlet tap is fully open before attempting to restart.
That the water inlet filter is not clogged (a blocked filter restricts flow and activates the pump protection).
That the device is not in thermal protection (if it has been used recently, wait several minutes before trying again).

If after these checks the device still does not start, contact an authorized Nilfisk service center for professional diagnosis.

Question 6

Why won't my NILFISK MH 4M pressure washer start even though it has power?

Accepted Answer

If your NILFISK MH 4M does not start despite having a proper power supply, check the following points:

1. Power Supply and Connection

Ensure that the rated voltage indicated on the electrical box matches your local installation (generally 230V or 400V depending on the region).
Inspect the power cable along its entire length for damage, cracks, or cuts. Never use the machine if the cable is damaged.
Test the wall socket with another device to rule out a problem with the power source.

2. Safety Circuits and Protections

Check that the water supply is turned on: open the water tap before attempting to start the machine. The MH 4M has a safety feature that prevents starting without water flow.
Ensure that the water inlet filter is not clogged. A clogged filter blocks the flow and may activate the pump protection.
If the machine has recently operated, it may be in thermal overload mode. Allow it to cool down for a few minutes - it will restart automatically.

3. Mechanical Checks

Place the machine on a flat and stable surface.
Check that the hose with trigger handle is properly connected and not jammed.
Press firmly on the power button ensuring it fully engages to the stop.

If after these checks the machine still does not start, contact an authorized NILFISK repair service for a professional diagnosis.

Question 7

What to do when the red, orange, and green indicators light up simultaneously on the NILFISK SC351?

Accepted Answer

When the three LEDs (indicators) red, orange, and green light up simultaneously and steadily on the handle of the NILFISK SC351 when connecting the battery charger to the electrical network, it indicates a serious problem with the battery. This simultaneous lighting of the 3 indicators is a specific alert signal: the battery is either damaged or excessively discharged beyond normal charging capacities.

Diagnosis: The green indicator normally indicates that the battery is charged and the machine is ready for use. The yellow indicator signals a semi-discharged battery requiring a recharge. The red indicator indicates a completely discharged battery. However, the simultaneous and steady lighting of all three indicators exceeds these normal conditions and reveals a battery malfunction.

Recommended action: In this situation, it is imperative to immediately contact an authorized NILFISK after-sales service. The battery cannot be restored by a simple recharge. The authorized service will either perform a complete restoration of the battery's functionality or replace it entirely if it is too damaged. Do not attempt to continue charging the battery or using the machine in this state, as this could worsen the damage.

Prevention: To avoid this situation, charge the battery regularly when the yellow indicator (semi-discharged battery) is on and never leave the battery in a completely discharged state for long periods. An excessively discharged battery loses its ability to be properly recharged.

Question 8

How to empty the hopper of the NILFISK SR 1601 B industrial cleaner?

Accepted Answer

To empty the hopper of the NILFISK SR 1601 B industrial cleaner, follow the steps below:

1. Turn off and unplug the device

Before any handling, ensure that the device is turned off and unplugged to guarantee your safety.

2. Remove the hopper

Locate the hopper on the device. Depending on the model, it may be secured with clips or screws. Carefully detach it by releasing these fasteners.

3. Empty the contents

Lift the hopper and empty the collected debris into a trash can or suitable container. Do this gently to avoid splashes or dust dispersion.

4. Clean the hopper

After emptying the hopper, clean the inside with a damp cloth or brush to remove residues and prevent bad odors or clogging.

5. Reattach the hopper

Replace the hopper on the device, ensuring it is securely fastened and sealed to prevent any dust leakage during use.

By following these steps, you ensure optimal operation and good hygiene of your NILFISK SR 1601 B industrial cleaner.

Question 9

How to adjust the pressure on a NILFISK CONTRACTOR MASTER pressure washer?

Accepted Answer

To adjust the pressure on your NILFISK CONTRACTOR MASTER pressure washer, follow these simple steps:

1. Locate the pressure adjustment button or knob

On the CONTRACTOR MASTER model, you will generally find a pressure adjustment knob or button on the lance or directly on the body of the device. This control allows you to adjust the force of the water being projected.

2. Adjust the pressure

Turn the knob clockwise to increase the pressure.
Turn it counterclockwise to decrease the pressure.

3. Test the pressure

After adjustment, pull the trigger on the lance to test the pressure. Do this from a safe distance to avoid damaging surfaces or injuring yourself.

4. Safety tips

Always wear protective gear such as goggles and gloves.
Never direct the jet towards people, animals, or fragile surfaces.

By properly adjusting the pressure, you optimize the effectiveness of your cleaning while protecting your surfaces and equipment.

Question 10

How to remove the inner filter of the NILFISK 626 vacuum cleaner?

Accepted Answer

To remove the inner filter of your NILFISK 626 vacuum cleaner, it is essential to follow the correct steps to preserve the quality of the main filter, which has a surface area of 16,000 cm².

Step 1: Prepare the vacuum cleaner
Start by completely unplugging the NILFISK 626 vacuum cleaner from the electrical outlet to ensure your safety. Wait a few minutes for the device to cool down if you have just used it.

Step 2: Access the motor and filter
The inner filter is located inside the motor unit of the tank. To access it, you must first remove the motor assembly by locating the attachment points on the tank (usually hinges or side clips). Gently lift the motor/filter section from the tank while ensuring you support the weight of the assembly.

Step 3: Remove the inner filter
Once the motor unit is accessible, the main filter becomes visible. Carefully grasp the filter by its lower part and slowly extract it. The filter may be held by clips or simply placed in its housing.

Step 4: Clean the filter
To maintain optimal performance of your NILFISK 626, regularly clean the filter. Never immerse the filter in water and do not brush it directly. Instead, proceed by gently shaking: hold the filter and shake it gently up and down to dislodge the dust. For deep cleaning, you can use another vacuum cleaner to gently vacuum the surface of the filter. Normally, 3 to 4 consecutive shaking movements are sufficient to maintain optimal performance.

Step 5: Reassemble and close
After cleaning, reinstall the filter in its housing, ensuring it is properly positioned and stable. Then replace the motor assembly on the tank and make sure all hinges or clips are securely closed and locked before plugging the vacuum cleaner back in. Check that the assembly is airtight to avoid air leaks that could reduce suction performance.

Regular maintenance of the main filter helps maintain the maximum depression of 22.2 kPa and ensures optimal motor power. Perform this cleaning after each intensive use or at least once a week depending on your usage.

User manual NILFISK : user manuals and guides in PDF

Models NILFISK most viewed

Browse manuals NILFISK by appliance type

Recent questions about devices NILFISK