Field King is a top-quality company that’s been around for more than 50 years. They’re known for manufacturing powerful and easy-to-use backpack sprayers. The Field King Backpack Sprayer is one of the best sprayers in its class.

This 4-gallon sprayer model is a lightweight and easy to operate sprayer perfect for small and large jobs around the home, garden, farm, or ranch. If you have a large job to do, your only option is to get a larger pump sprayer or rent a sprayer from a local business.

Field King 190328 Backpack Sprayer

Field King 190328 Backpack Sprayer

Field King Max Backpack Sprayer

Field King Max Backpack Sprayer

Field King Professional Backpack Sprayer

Field King Professional Backpack Sprayer


Key Features of This Field King Backpack Sprayer

This model is a unique way of managing weeds, insects, and other pests in your garden. With this model, you can quickly get rid of weeds, pests, and insects without damaging your plants. Let’s have a look at the main features.

  1. Internal, No-Leak Pump promotes safety when using chemicals with its interior, non-pressurized ergonomic design with affordable price.
  2. A pressurized flow pump delivers up to 150 PSI.
  3. The premium, lockable shut-off requires the activation of a pressure relief valve. This safety feature will not allow for overpressure or under pressure in the system to occur. It can help prevent leaks that may arise from pumping out chemicals before finishing jobs.
  4. The 21-inch poly wand with high-quality Viton seals can handle wet powders and liquids, making it ideal for all applications. It will do an excellent job of replacing an internal piston and diaphragm backpack.
  5. This model is safer than other brands. The simple access pump is designed to make changing your water treatment system seals as easy as possible. The pump comes with four different nozzles that allow you to completely clean and flush your system.

Internal Paddles

The multi-purpose Spray-Mixer has many benefits. It can be used to mix liquid mixtures, quick-dissolve powders, and even water-soluble solutions. This machine can also operate in reverse, mixing powders or liquids into water.

The uniform spray pattern is a secondary benefit of this machine because it allows for more accurate application. This machine has a test report that shows it can handle up to 1 million cycles of mixing without failure. YOu will get a reasonable flow rate and liquid filtration 

Internal Pressure Chamber

with a capability of reaching up to 150 PSI, the spray pressure chamber is durable, must-have equipment that will help you reach hard-to-reach areas. It is 65% more substantial than other backpack sprayers. It allows you to create more precise cone spray patterns and perform more effectively in your work.

No Tools Requires

The 190328 patented gear pump is designed with minimal interruption (60% less), and it can be repaired in minutes without tools. All these pumps are built with high-quality, durable components that can take the abuse of outdoor applications. They are durable and will exceed your expectations.

This large holding tank is ideal for more considerable debris removal with a large opening and filter basket while filling.  The single-way valve stops leaks if the polyethylene tank is on its head.

Easy to Clean

Cleaning out the sprayer is a good idea after each use. Once you have finished the job, it is best to empty the canister and clean up the other machine parts.

  1. To clean a pressure washer, perform the following steps:
  2. Fill the polyethylene tank with clean, cool water.
  3. Place the tank in the center of the machine and fill the rest of the hopper with water.
  4. Please turn on the machine and allow it to run for at least 30 seconds.
  5. Spray the tank and hose with clean, cool water.
  6. Let the water drain out of the pump and hose while turning off the pressure washer.
  7. Remove the tank material from the machine and empty it.

Difference between the 190328 and the 190348 backpack sprayer

The 190328 backpack sprayer is the most durable model on the market. It contains an adjustable padded comfortable shoulder strap, a full support waist strap, and chest snap belt, an adjustable back pad, and a foldable pump handle for easy transport.

The 190348 Field King model is the most transportable backpack available in the market. It contains a deluxe padded harness, a full back pad, a comfortable waist belt, and a pump handle for easy transport.

These models come with a no-leak pump design and even a dual-function strap clip to ensure safe storage. The 190328 model also comes with a changeable filter and four excellent nozzles for use in many applications.

Quality Pumping

Pumping is convenient and easy to use. With a large spray tank, you can spray with less effort, and the nozzles ensure that you get consistent pressure. A few users complained about the noise, but this model has a large fuel tank capacity and a pitcher that can be used on either side for both left and right-handed use.
As a wetting agent, this sprayer is a natural way to refresh your product, mainly when used with our Agitator bottle. When you pump, the piston and paddles move the solution around to mix it with the water. In addition, this sprayer is made with a rotating agitator, which makes it easier to ensure that you do not lose any of the solutions during storage.

What is the capacity of this backpack sprayer in gallons?

The polyethylene tank can hold up to 4 gallons of liquid. The markings on the sides of the tank can indicate the level of liquids contained. If it’s complete, it can balance 50 pounds. To place it behind, you can hold it in your hands and climb into the connector attached to the top of the tank.

Will this model work with organic fertilizers that contain some small stuff?

Use high-performance paint that requires a fine paper filter. The best way to use organic fertilizers is with a diaphragm-type sprayer. A piston-type of sprayer won’t work as well.

How far does this 4-gallon tank model spray?

I can reach 8-12 feet into the air with the adjustable nozzle. If you use a suitable power nozzle, you can make your garden smaller and spray higher up. Pumping power nozzles is challenging and requires a lot of strength. It depends on what nozzle you have and what tip you used.

What is the length of the padded shoulder straps?

At first glance, this padded strap-on sprayer looks like a cheap device, but it’s very comfortable and is also very long. I’ve only used it once so far, and it’s necessarily long for me. With a bit of practice, you’ll be able to get the hang of how to use it.

Field King Sprayer Parts

Can you use the remaining weed killer solution without causing any harm to the plastic container?

I am not sure if it would damage the plastic or cause problems with the seals. You can clean it out by filling it back up with water and spraying it down. Also, You may put dish soap in there to help break down any residue left from harmful chemicals.


  • Internal parts are made of the long-lasting and adjustable brass nozzle
  • For maximum chemical resistance, excellent Viton seals are used
  • The handle can be used in both left or right hand
  • This model provides joint carry handle and wand storage
  • Professional Piston Backpack Sprayer
  • Simple design and comfortable grip
  • An ideal choice for your lawn and garden


  • Sometimes the pressure regulator doesn’t work
  • Customer service is not up to the mark
  • Not an excellent choice for a battery-powered pump

Field King Backpack Sprayer Manual

Field King Backpack Sprayer Replacement Parts

Final Words:

Field King 4 gallon backpack sprayer is an extremely popular backpack sprayer. Homeowners and farmers use it for applying pesticides, fertilizers, weed killers, and other chemicals. The sprayer is sturdy and has a high capacity.

You can use it for spraying liquids on large areas like farms. The Field King 4 gallon backpack sprayer has a tank capacity of 4 gallons and a single-hand pump. The product is affordable, and it comes with a 12-month warranty.

This 4-gallon sprayer unit is ideal for both commercial and home use. It comes with a high-quality pump that delivers an output of 3.9 liters per minute, and it can be used to spray just about any liquid in a concentrated stream that’s up to 15 feet away. This sprayer has a wide mouth opening at the top, so you can fill and clean it quickly, and it needs little pressure to operate.