Foam Cannon Only Works Upside Down | Let’s Fix

A foam cannon is a cheap yet practical tool that can ease the process of lubricating and washing one’s car. However, this practicality can become useless if it doesn’t work in its proper orientation. Many users seem to face this particular issue while using a foam cannon.

A foam cannon only working upside down is a common malfunction. While a lot of users may think that their cannon is broken, usually, a foam cannon can work upside down for a number of reasons, such as incorrect soap to water ratio, a clogged pickup tube, a broken orifice, or even a simple thing such the wrong water temperature.

Whichever reason it may be, usually, the solutions are quite simple. In this article, we’ll try to give you an answer for why your foam cannon only works upside down and how to remedy this particular issue.

How Does A Foam Cannon Work?

Before we jump to conclusions, let’s learn about what foam cannons are and how they work.

A foam cannon is a piece of washing equipment that is used to wash vehicles, as well as motorcycles. It is generally operated with a pressure washer to generate foamy suds. It has a couple of components that make up the entire body of the cannon. These are –

  1. Canister: The bottle/jar that holds the soap and water.
  2. Body Assembly: The metallic piece that connects and holds all the other components together.
  3. Pressure Washing Fitting: A small screw-like component that is attached behind the body assembly.
  4. Filter: Situated inside the nozzle assembly, the filter is a small component that agitates the hot water and soap to create thick foam and filters out dirt and debris from the soap mixture.
  5. Nozzle Assembly: A nozzle mechanism that can control the spray pattern and how the soap solution will be sprayed on a surface.
  6. Valve Knob: A knob that controls how much soap solution is pushed through the nozzle.
  7. Orifice: A small screw-like component that controls the water flow rate (GPM) and water pressure (PSI) of the pressure washer through the nozzle.

Hot water and soap are mixed inside the canister to create a thick, foamy soap solution. The solution is then pushed through the nozzle by the pressure washer, the strength of which is controlled by the valve knob. Several catalysts are necessary to create proper, foamy suds.

Why Does My Foam Cannon Only Works Upside Down?

A couple of contributing factors can be why your foam cannon isn’t functioning in its vertically correct position and only working when it’s upside down.

When we say “not working,” it can mean either one of two things. One, it is not functioning at all and failing to push out any soap solution, or the current it’s pushing out is weak and fails to clean the car effectively. Two, it is not creating foamy suds but rather pushes out runny water mixed with soap.

If you’re having the first problem, there are likely several contributors at work here. Bear in mind this could be the result of one or several of these issues.

  • Low Pressure: One reason your foam cannon only works upside down and not in its normal vertical state is that the pressure inside the canister is weak.  This weak pressure could be due to the pressure washer you’re using, which isn’t generating enough pressure inside the canister. When you flip the foam cannon, the soap solution directly hits the nozzle and works properly.
  • Water Pressure: Another reason your foam cannon only works upside down is the wrong water pressure – PSI (pressure per square inch) and flow rate – GPM (gallon per minute). If you use a foam cannon with inaccurate orifice dimensions, mismatching with your pressure washer’s PSI and GPM, it will likely result in your foam cannon not working properly or at all.
  • Inorrect Soap to Water Ratio: If you’re having the second problem, the soap solution could be runny for a number of reasons. One reason is that you’re not using enough soap.
  • Loose/Broken Orifice: Another reason is that the valve knob and/or the orifice are loose or broken, which prevents the water from mixing with soap and creating foamy suds.
  • Water Temperature: The last reason is mixing cold water with soap, as soap doesn’t mix as well with cold water as it does with hot water.

How to Fix Upside Down Issue on My Foam Cannon?

If your foam cannon is only working upside down and not working in its normal vertical position, try these simple solutions.

  • If you’re using a pressure washer, make sure it can deliver a sufficient GPM flow and PSI with your foam cannon. Whether you use a gas-powered pressure washer or an electric pressure washer, select one that has at least a GPM of 1.75 and a 1900-2000 PSI rating.
  • Make sure the orifice that comes with the foam cannon has the proper dimensions to match the GPM and PSI of your pressure washer. For example, if you have a GPM of 1.3 to 1.8, with low to medium pressure as 1700-2000 PSI, the correct orifice dimension for your foam cannon would be 1.1 mm.
  • Clean/rinse the nozzle with clean water every time you wash your car.
  • Make sure the suction straw inside the canister is not blocked by soap or debris. If the straw is blocked, take it out and cut it at an angle so it can suck the soap solution easily.

Also Read: Can You Use Any Soap In A Foam Cannon – Fact-based Explanation

Foam Cannons vs Other Methods

Foam cannons can be quite expensive, especially if you don’t wash your car too often. If you’re looking for something cheaper, foam guns or even the two buckets method can be useful for you. However, for the avid user, foam cannons vs foam guns is a legitimate question mark, as both have their pros and cons.

The same goes for people who are torn between foam cannons vs two buckets, as a lot of people prefer to hand scrub and wash their car. All these methods have their different pros and cons. The general advice is to study your preferred choice of equipment and see if it serves your purpose or not.


A foam cannon is an imperative tool for a car owner. It saves the cost of a car wash and grants you the satisfaction of cleaning your car.  However, a faulty tool wastes your time and money. Follow the methods mentioned here to use your foam cannon properly. Thanks for reading.

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