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Cordless Sprayer Not Pumping? GM ASL 8 Fixes

From clogged nozzles to pump problems, learn how to get your sprayer working again and restore a fine mist.
From the Westfalia editorial team · Updated on 20.07.2026
Created and reviewed by the Westfalia editorial team.

In short: If your cordless sprayer is not pumping, first check the battery and contacts. The problem is often caused by a clogged nozzle or a dirty filter on the suction hose. Clean these parts thoroughly. Also make sure there is no air in the system and that the spray solution has not clumped.

You are in the garden, ready to care for your plants, but your cordless sprayer is not working. Instead of producing a fine spray mist, it only sputters or produces nothing at all. This problem is frustrating, but it can often be fixed quickly. Most cordless sprayer problems have simple causes that you can resolve yourself in just a few steps.

In this guide, we focus on the most common causes and show you practical solutions, especially for the popular GM ASL 8 model. From a clogged nozzle to a stalled pump, we will guide you through the fixes step by step.

A working sprayer is the foundation of effective plant protection. Most problems are not caused by defects, but by minor blockages or insufficient maintenance. Regular, simple maintenance prevents 90 % of all repairs.

— Klaus Richter, master gardener

A reliable helper for these tasks is the Cordless Li-Ion Sprayer 8 Liter "GM ASL 8" (

). With its powerful battery and comfortable carrying strap, it makes it easier to apply liquid fertilizer, plant protection products, or weed killer over large areas. However, even the best device needs to be used correctly to remain powerful and reliable over the long term.

How can you tell if your cordless sprayer has a problem?

Problems often show up through clear signs. If you know what to look for, you can quickly narrow down the cause. Pay close attention to your device when it does not work as usual.

The most common symptoms are:

  • The pump does not start: You press the switch, but cannot hear the motor. The problem is probably with the power supply or a blocked motor.
  • The pump runs, but no liquid comes out: The motor hums, but the nozzle stays dry. Air in the system, a blocked suction path, or a problem with the pump itself is often the cause.
  • The device sprays at low pressure or sputters: The spray is weak and uneven. This almost always points to a blockage around the nozzle or filter.
  • Liquid leaks from unexpected places: Leaks at connections, hoses, or the housing indicate loose parts or damaged seals.

If you notice one of these problems with your GM ASL 8, work through the following fixes systematically. Always start with the simplest and most likely cause.

The most common problem: why your sprayer is clogged and what to do

A blockage is the number one cause of malfunctions. Spray products often contain fine particles that can build up in the narrow channels of the nozzle or filter. Homemade solutions or powder-based products that have not dissolved completely are especially likely to cause clogs.

How to clean the nozzle, step by step

The nozzle is the narrowest point in the entire system. Even the smallest particles can settle here and block the flow. Careful cleaning will often solve the problem.

  1. Depressurize the device: Switch off the sprayer. Press the spray lever until no more liquid comes out and the pressure has been completely released.
  2. Unscrew the nozzle: Twist the nozzle cap off the spray wand. Make a note of the order of the individual parts. A nozzle usually consists of a cap, a small sealing ring, and the nozzle insert itself.
  3. Clean mechanically: Place the parts in a small bowl of warm water with a drop of dish soap. Use an old toothbrush or a special nozzle-cleaning needle to carefully clean the small openings. Blow firmly through the openings to loosen any remaining particles.
  4. Rinse and reassemble: Rinse all parts thoroughly with clean water and reassemble the nozzle in reverse order.

Check the filter on the suction hose

Inside the GM ASL 8 tank, there is a small filter at the end of the suction hose. It keeps larger dirt particles or clumped product from entering the pump. If this filter is blocked, the pump can no longer draw in liquid.

Pull the suction hose out of the tank and inspect the small screen at the end. It is often covered with a slimy layer or solid particles. Unscrew the filter and clean it under running water with a brush. After cleaning, secure it firmly back onto the hose.

Clumped spray products as a cause

Always mix spray products exactly as directed. Fill the tank with water first, then add the concentrate. This prevents undissolved residue from settling on the bottom. Before filling the tank, strain homemade mixtures such as nettle brew through a fine sieve or cloth. Browse our fertilizer category for a wide selection of professional and ready-to-use products.

Important note

Always wear suitable protective gloves and safety goggles when handling plant protection products and cleaning the device. Dispose of leftover liquids and cleaning water responsibly. Never pour them down a household drain or into bodies of water.

The Pump Has Stopped: What to Do If Your Cordless Sprayer Is Not Pumping

If no water comes out even after cleaning the nozzle and filter, the problem may be with the pump or power supply. Don't worry—these solutions are often simpler than you might think.

Check the Battery and Contacts

It may sound obvious, but the battery is a common source of problems. Make sure it is fully charged. Remove it from the device and reinsert it to rule out a loose connection. Check the gold or silver contact surfaces on the battery and in the sprayer's battery compartment. Moisture or dirt can sometimes cause a light coating to form, disrupting the flow of electricity. Carefully clean the contacts with a dry cloth.

The battery is a key component of many modern power tools. If you own several devices from the same system, you can easily swap the battery to test whether it is working properly. The Westfalia range also includes powerful tools such as the 10,8 V cordless impact drill/driver PowerMaxx SB Basic (

). Suitable power sources such as the "EasyFlex" value pack () or the more powerful "EnergyFlex" value pack () help keep your collection of devices ready for use.

Air in the System? How to Bleed the Pump

If the device has been running empty for a long time or is refilled after cleaning, air can become trapped in the pump and hoses. The pump may then run but be unable to draw in water because it is only pumping air.

Fill the tank with a little clean water. Hold the spray wand lower than the tank and press the switch. It can sometimes help to gently shake the device so that the air bubbles can rise towards the tank. Let the pump run for a while. After a short time, it should draw in the water and push the air out through the nozzle.

Pro tip

After every thorough cleaning, run a test with clean water. This ensures that all blockages have been removed and that the device works properly for its next use with expensive spray solution. It also flushes any remaining cleaning agent from the system.

Mechanical Blockages in the Pump

In rare cases, a foreign object may pass through the intake filter and block the diaphragm pump. This is often indicated by an unusual, strained motor sound or the motor stopping completely. Disassembling the pump is a job for experienced users. Consult the operating instructions for your GM ASL 8. It is often enough to open the pump housing and remove the foreign object.

Proper Care and Maintenance: How to Prevent Problems with the GM ASL 8

The best repair is the one you never need. With regular and proper care, your cordless sprayer remains a reliable partner for all your garden and outdoor tasks.

Clean After Every Use

Make it a habit: clean the sprayer after every use. Empty the tank completely and rinse it with clean water. Then add some fresh water and spray it through the system until only clean water comes out of the nozzle. This prevents aggressive substances from damaging the seals or residues from drying and causing blockages.

Consistent cleaning is not a tedious chore; it is an investment in the service life of your device. Five minutes of care after use can save hours of troubleshooting and frustration next season.

— Westfalia Technical Team

Proper Storage in Winter

Frost is the greatest enemy of water-carrying equipment. Freezing residual water can burst hoses, seals and even the pump housing. Before winter, make sure the device is completely empty and dry. Store it in a frost-free place. It is best to remove the lithium-ion battery from the device and store it at room temperature with a charge of around 50-70%.

Choosing the Right Spray Solution

Not every liquid is suitable for use in a sprayer. Do not use solvent-based, corrosive or highly flammable chemicals. These can damage the plastic parts and seals of the GM ASL 8. When applying lawn fertilizer with weed killer, make sure it is suitable for sprayers and dissolves completely without leaving residue.

Additional Advice

Keep a small log of the products you use. This will help not only with garden planning but also with troubleshooting. If a problem occurs after using a particular product, you will know that you may need to dilute or filter it more thoroughly next time.

By following these simple but effective troubleshooting and maintenance tips, you can ensure that your GM ASL 8 cordless sprayer is always ready for use. A well-maintained device not only works more reliably but also delivers optimal spraying results, helping to protect your plants effectively.

Frequently Asked Questions

What should I do if my sprayer will not start even though the battery is fully charged?
Check the battery contacts on the device and battery for dirt or corrosion and clean them. Make sure the battery is properly locked in place. Also check that the device's main switch is working correctly. In some cases, the pump motor may be blocked.
How do I clean the nozzle on my GM ASL 8 properly?
Unscrew the nozzle with the device depressurised. Soak the individual parts in warm water with a little washing-up liquid and carefully clean the fine openings with a soft brush or needle. Rinse everything thoroughly with clean water before refitting the nozzle.
Why is my sprayer spraying unevenly?
An uneven spray pattern usually indicates a partially blocked nozzle. Clean the nozzle thoroughly. Low pressure may also be the cause. Check the battery level and make sure the intake filter in the tank is clean and the pump can operate freely.
Can I use any plant protection product in my cordless sprayer?
Only use liquid products approved for use with sprayers. Homemade mixtures or powdered products that do not dissolve completely can clog the nozzle and pump. Always follow the manufacturer's instructions for the spray product and the operating instructions for your device.
How do I store my cordless sprayer over winter?
Empty and thoroughly clean the tank and the entire system with clean water. Allow all parts to dry completely. Store the device and battery separately in a dry, frost-free place. A charged battery will cope better with the winter break.
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