Solo Backpack Sprayers: FAQs Answered

Solo backpack sprayers are my preferred choice when it comes to spraying my lawn and around buildings. They are very affordable and yet they are durable enough for the homeowner who doesn’t want to spend hundreds of dollars on something they don’t use every day. 

Most backpack sprayers are very similar but I’ve noticed when it comes to Solo brand backpack sprayers there are a few specific things that people often ask about. I have worked with Solo Backpack sprayers for years so I decided to use my experience to answer those questions. 

Solo Sprayer Nozzles 

Solo typically includes a variety of different spray nozzles with their backpack sprayers: An adjustable nozzle, a flat fan nozzle, a cone tip, and a solid stream tip. 

What is each nozzle for?

  • Adjustable Nozzle: The adjustable nozzle is a versatile tip great for spot spraying herbicides, pesticides, and cleaning products. You can change it from a wide, full cone, to a more focused stream that can spray 20 + feet. 
  • Flat Fan: Flat fan nozzles are designed for spraying in a row or plants, or coating surface evenly like staining a deck. 
  • Hollow Cone: Combining the solid stream nozzle and the swirl plate will create a cone spray pattern. This is ideal for orchards, shrubs, and trees.
  • Solid Stream: The solid stream tip basically gives you the same solid stream as the adjustable nozzle but at a lower rate. The tip size is smaller and can reach a bit farther than the solid stream setting on the adjustable nozzle. 

How Do You Change a Solo Sprayer Nozzle?

The nozzles that come with a Solo backpack sprayer fit inside a cap that then threads onto the end of the spray wand. 

Changing the nozzles is straightforward. But if you want to switch from the adjustable nozzle to one of the other nozzles you have to remove the red adjustable nozzle from the cap. 

The adjustable nozzle is made of two pieces. While the nozzle is on the end of the spray wand, unscrew the tip. Then you can remove the cap from the wand along with the other half of the adjustable nozzle. 

There is a small screen inside the end of the wand. Don’t lose this. The nozzle and cap hold the strainer in place. 

When the tip is removed simply Place the new tip in the cap and screw it onto the wand. Be sure the screen is put back inside the cap. It not only filters debris but also seals up the tip. 

The adjustable tips do not need to be installed in any specific direction but you will want to make sure your fan is in the proper direction as you tighten the cap. 

If you want to utilize the hollow cone spray tip, then you must combine the solid stream tip and the hollow cone swirl plate together. 

Now, changing nozzles is pretty easy with a new wand but after lots of use, the nozzle cap tends to get stuck and is hard to remove. 

You can use pliers to help unscrew stubborn nozzles but the plastic is easy to break, crack, or warp with a pliers. Using an old rag can help. Wrap the rag around the nozzle to keep the teeth of the pliers from chewing up the nozzle cap. Turn firmly but gently.

Video of Changing a Solo Sprayer Nozzle

Can I Use Other Nozzles on a Solo Backpack Sprayer?

Yes, you can use other nozzles that do not come with your Solo brand sprayer. The cap will hold and seal with many other nozzles. 

I have used TeeJet brand spray nozzles with my Solo backpack sprayer without issue. The majority of TeeJet flat fan and flood tips will fit inside the Solo retaining cap, but some of the larger size tips may not. TeeJet 5500 series adjustable nozzles will also thread onto the end of a Solo backpack sprayer wand. 

How Do I Install The Handle/Lever on A Solo Backpack Sprayer

The “deluxe” model Solo backpack sprayers have a handle designed to swivel upright so they can be stored more easily. If the handle is installed incorrectly, not only will you not be able to swivel it upright, but you will have a hard time reaching it to pump the sprayer.

The handle slips over the shaft under the tank that connects to the diaphragm.  Before you can slide the handle in place, you must remove the bolt from the shaft. The bolt is a bit hard to get started but it works when the holes are lined up. 

This video shows the correct orientation and how to install the handle/lever:

What to Do When Your Solo Backpack Sprayer Will Not Pump or Hold Pressure

Like other Backpack sprayers and hand pump sprayers, solo sprayers need to be sealed up tight to hold pressure. As you pump the handle, the liquid is forced into the pressure cylinder. When you pull the trigger on your sprayer wand, this stored pressure is released, and this generates the flow needed to make the sprayer function. 

If your sprayer will not hold pressure then it is likely that you have a bad seal in the pump assembly. The pump assembly must be airtight. A crack or a worn-out o-ring could be the cause. One common issue can be the check valve on the inlet of the pump assembly. This valve allows liquid into the pressure chamber and keeps it inside. This is how the sprayer builds pressure as you pump the handle. You can see a full explanation in this article that shows what to check when your backpack sprayer won’t pump.

Why Is My Solo Sprayer Leaking?

A leaking sprayer can be very annoying. If your solo sprayer is leaking there are a few possible causes. Let’s look at some common leak areas and what to do:

Leaking from the nozzle: It is common for the spray nozzle to keep dripping, even after you let go of the trigger. This is because some liquid is still inside the wand extension. All the liquid from the trigger handle to the tip will drain out slowly after you release the handle. 

You can insert a small check valve at the end of the wand just under the spray tip. Solo offers this item but in many spray wands, you can use a TeeJet check valve as well. This article on adapting spray tips to different wands covers this in more detail.

Other Common Possibilities for Leaks on Solo Backpack Sprayers

  1. Loose connections: Check the hose connections, as well as each threaded wand connection. If it is loose, tighten it to ensure a secure fit. You can use some soft setting thread sealer if a threaded connection is leaking even when tight. If this does not work, you may need to replace the wand or hose.
  2. Worn or damaged Seals: The trigger wand has a seal inside. Over time, this seal can wear out or become damaged, causing leaks. You can replace this seal to solve the problem. You can use petroleum jelly to lubricate seals/o-rings to keep them working properly.
  3. Cracked or damaged: If the wand itself or tank is cracked obviously it will leak. A wand can be replaced, but a tank means either fixing the crack (which can be very hard) or getting a new sprayer. To attempt to fix a crack in the tank you would need a product like this plastic welder.

Chemical Compatibility 

Leaks can be caused by damage to the seals or other materials on the sprayer. Solo backpack sprayers are made of nylon hose, poly tanks, and Viton seals. Although they will handle a broad range of chemicals, there may be some products or other chemicals that are not compatible with these materials. Fuels, cleaning agents, acids, etc may cause leaks. 

If you have a piston pump-style backpack sprayer you should stay away from using wettable powders. They can cause damage to the piston and cylinder. A diaphragm-style pump is suited to handle abrasive wettable powders. It is more forgiving than the piston style. 

You can find chemical compatibility resources at Cole Parmer. You can also see the tests I did with various chemicals with my sprayers. 

How Do You Unclog a Solo Sprayer?

If you have a clog in your Solo sprayer, one of the first things to check is the nozzle strainer. Remove the nozzle and cap to access the strainer. Check for any blockages in the tip and the strainer. If you find debris or dirt, clean the nozzle with a small brush and flush it with clean water.

If you still have a clog then you might have debris in the trigger handle, hose, or the pump chamber outlet. Overtime residue from chemicals can build up and cause a plug. Empty your sprayer, then take apart the spray wand, hose connections, and remove the pump assembly. 

Rinse and clean each piece. Use a wire brush or pipe cleaner to clean out the components.

How Do You Adjust the Pressure on a Solo Backpack Sprayer?

If you have a “deluxe” model Solo backpack sprayer. You can adjust the pressure setting of your sprayer. Inside the tank is a pressure chamber. On the top of this chamber is a dial with four settings. When the tank is empty you can open the lid on the sprayer, remove the basket strainer, and access this dial. 

The settings are 15, 30, 45, and 60 psi. The higher pressure means your sprayer will push more liquid out over the same amount of time. To change the setting, push down on the dial and turn it to the desired setting. Then replace the strainer and lid. The pressure setting dial can be removed and replaced with a plug. This will forgo the regulator and allow you to pump up the sprayer to a pressure above 60 pounds. 

What Pressure Setting Should I Use? 

The reason for the different pressure settings is to help you regulate the output of your Solo sprayer. Combined with your walking pace, and application method, your PSI will determine the amount of liquid you apply to a given area. 

Determining the optimal pressure setting will require you to calibrate your backpack sprayer. This way you can determine how much you are currently applying with your backpack sprayer, and if you need to adjust the pressure to put out more or less liquid as you spray. If you are looking for more information, then check out this article on calibrating a backpack sprayer.

How Do You Prime a Solo Backpack Sprayer?

Priming a Solo backpack sprayer is easy. Once you have filled the sprayer, you need to pump the handle repeatedly to build pressure. Before you begin to spray, pull the trigger and pump the handle until all air is out of the sprayer.

How Do You Change the Diaphragm on a Solo Backpack Sprayer?

The reality of using any backpack sprayer with pesticides and other chemicals is that components will wear out. The diaphragm on a Solo backpack sprayer comes into direct contact with the liquids in your sprayer, and if it wears out or cracks you have leaks and won’t be able to build pressure. Fortunately, Solo does offer a diaphragm repair kit

To replace the diaphragm, you must disconnect the diaphragm lever and brackets from the pump handle. Then remove all the screws that keep the diaphragm housing and flange together. Then you can remove the diaphragm and replace it with the items in the repair kit.

The repair kit also comes with O-rings and a spring for the regulating valve on the pressure chamber, and the seal and plate for the inlet check valve.

Additional Resources

This information should help you operate and fix your Solo backpack sprayer. If you are new to spraying you may find these resources about sprayer calibration and troubleshooting helpful:

Troubleshooting a Backpack Sprayer

Are Backpack Sprayers Worth It?

How Much Area Can a Backpack Sprayer Cover?

Backpack Sprayer Buyers Guide

Shane Blomendahl

I have more than a decade of experience using, building, studying, and testing sprayers in several applications. With the knowledge I have gained I want to provide straight forward and detailed answers for DIY homeowners, farmers, and commercial turf and tree care pros.

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