Match the orifice to your machine's flow rate rather than its stated pressure. Lower-power machines such as the Karcher K2 to K4 or Nilfisk C110 to C130 work best with a narrower 1.1 mm orifice. Higher-power machines such as the Nilfisk P200, Kranzle K10, or Karcher K7 need a wider 1.35 mm orifice to avoid excessive back-pressure. Using the wrong size gives weak foam or stresses the pump motor.

The most common cause is incorrect PIR (product injection ratio) for your specific lance and pressure washer combination. The same 200 ml of product gives roughly 2% PIR on an MJJC Pro V2 paired with a Karcher K4, but only about 1.1% PIR on an MTM PF22.2 on the same machine. Calculate your PIR by filling the cannon with water only, dispensing the full cannon into a bucket, then multiplying that volume by your target percentage to find how much product to add.

Yes, set the dial to maximum and leave it there. The dilution you mix in the bottle controls foam strength, not the dial position. Varying the dial between your PIR calculation and the actual wash changes the draw ratio and invalidates the calculation you just did, meaning your product concentration at the panel is no longer what you intended.

No. Wetter, longer-dwelling foam is more effective than thick shaving-cream foam. Very thick foam dries out quickly, loses contact with the surface, and gives the surfactants less time to react. Foam that is visually impressive but fast-drying is counter-productive for a pre-wash. The goal is foam that clings, runs slowly, and keeps the chemical in contact with the paint for the full dwell period.

After each use, clean the filters with distilled or deionised water to prevent soap residue and mineral build-up. If you use a spray-and-rinse foam sealant through the cannon, the polymer additives can gradually block the mesh filter. To clear a blocked filter, remove it and soak in descaler or white vinegar, or run undiluted wheel acid through the lance away from any vehicle to dissolve the deposits.