The Importance of Knapsack Maintenance and Replacing Parts

The Importance of Knapsack Maintenance and Replacing Parts

Why is it important?

Regularly servicing your knapsack sprayer is an extremely important job. If parts of the sprayer are becoming old and worn this could result in less effective spraying and could also shorten the life of the knapsack sprayer itself. It is also important to check the knapsack sprayer before the spraying season as there can be nothing worse than wanting to start spraying and realising that there is an issue.

With reputable brands of sprayer and the correct maintenance and care, knapsacks can live a very long life some people seeing over 20 years of use!

Tank Maintenance 

To get the most out of your knapsack it is  vital to ensure that they are cleaned after every use. It is standard practice to rinse the tank three times and clean it with a tank & equipment cleaner to ensure that there is no contamination left. Imagine a sprayer used with a total weedkiller such as Gallup Home & Garden for driveway weeds – which is then used to spray a fertiliser on a lawn. Unless washed out thoroughly, residues may kill the grass and require expensive and time consuming repair. Not only will triple rinsing help to prolong the life of the sprayer, it will also make sure that different chemical products won’t get mixed and have a negative impact on future spraying.

What parts might need changing?

‘You get what you pay for’….cheaper brands often need replacing entirely due to lack of spares but the better quality brands such as Mesto, Cooper Pegler & Matabi have a wealth of spare parts which ensures longevity and usability. There are two types of pump found on a backpack sprayer: piston & diaphragm. In both of these the rubber seals & o-rings are most at risk of perishing or cracking. Piston operated sprayers often require the cup seal to be greased. In the diaphragm knapsack the large rubber diaphragm underneath often requires replacement after a few years – especially when using ‘drying’ chemicals, such as iron sulphate.  Bad or damaged seals can easily result in leakages which would affect both the environment and the operator. For guidance on stripping down your knapsack see our video here.


Spray lances are also susceptible to getting damaged from being trodden on, driven over or nuts tightened to splitting. Hairline cracks in lances will end up wasting product and potentially affecting non-target areas. Triggers often get neglected and in-line filters within the hand grip especially need regular cleaning. The brass piston in the trigger fouls, leaks and gets stuck after years of neglect and flat washers often get lost over time. The good news is all these can usually be replaced…

What spares/parts can I purchase from ProGreen?

At ProGreen we offer a wealth of accessories and spare parts which make us a one-stop-shop from buying to servicing your knapsack sprayers. In the accessories section of our website you will find:

Cooper Pegler offer excellent knapsacks and a wide variety of spares. Take a look at our Cooper Pegler range here.

Alongside all of this we have many other accessories available, check them out here.