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Why isn’t my backpack sprayer working?

By 10th March 2023May 3rd, 2023No Comments

Common reasons your knapsack sprayer isn’t working

It’s that time of year… you’ve got your knapsack sprayer out of the shed/garage or wherever you have carefully stored it for the winter and it’s not working. Weeds are getting out of control in your garden or on your drive or moss is beginning to overtake your lawn.

Panic not! Issues with backpack sprayers are usually caused by parts such as valves, rings and bushings. They will most probably need a quick clean or replacing. Hopefully, the service kit you should have received with the sprayer will contain the replacement parts you need. Of course, regular and careful maintenance should prevent any issues and ensure your backpack sprayer lasts you for many happy years! Replace the wear parts regularly and ensure you have back up service kits on hand – they are inexpensive and will save you time and money in the long run.

Below, we offer a few key troubleshooting tips for common problems to get your sprayer spraying beautifully again (and which will hopefully save you having to go out and buy a new sprayer).

1. Why isn’t my backpack sprayer pumping?

First, and this might sound obvious, but check that you haven’t accidentally flicked the switch on the trigger into continual spraying mode. You would be surprised how often this happens and it can be quickly and easily resolved by switching it back off continual mode. Or, read on:

There is a lack of pressure in the pump (that much may be obvious!). Why?

This could be due to dirt or wear in the lower valves (see part 14 in two places in diagram below from our 20L Symmetrical Backpack) so clean or replace them.

Or, the dual bushing (16) needs changing.

2. Why is my backpack sprayer leaking from the top?

It has been filled above the maximum level so let out some of the liquid. Ensure it is filled only to the maximum level marked.

The tank lid is damaged or loose. Change or tighten it.

The pump-securing cap (7) or gasket (6) is damaged or loose. Change or tighten it.

The cap valve (4) is loose. Tighten.

3. Why is my backpack sprayer arm stiff

The suction tube (26) is damaged or loose. Change or adjust it.

Or, the lower valves (14) are damaged or dirty. Clean or change them.

4. Why is my backpack sprayer arm loose?

The lower valves (14) and dual bushing (16) may need changing.

5. Why is water dripping out of the spray lance of my knapsack sprayer?

The lance seal (43) might be damaged. Change it.

There may be air in the line. Spray upwards for a few seconds to see if this clears the problem.

Or, the discharge needle valve assembly (44) might be jammed. If so, apply some grease or change it.

We hope the tips above will solve your backpack sprayer issues. If not, please do call us on 01273 400092 and we will be happy to advise further.