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How to Run the Pro Mixer XL (and the Rinse Step Most People Skip)

There are over a hundred Pro Mixer XLs out in the field now. The ones that fail early almost always fail for the same two reasons, and both are avoidable. This covers what the XL actually is, how we set it for houses and roofs, the rinse step that most people get wrong, and the yearly maintenance that keeps it alive. Why it is called XL Most 12V soft wash mixers run half inch valves. Ours run 3/4 inch — valves and check valves both. There are three check valves in the system: one on water, one on soap, one on bleach. The reason is flow. Every check valve and every metering body is a restriction. At half inch, you feel it. At 3/4, the chamber the liquid is being metered through is substantially bigger and the flow does not choke down the way it does on a smaller block. We tested both before settling on it. Settings we actually use Water stays wide open, all the time. Everything else is metered against it. House wash: soap bumped on a little, bleach somewhere around the 1 mark. Good starting point, then adjust to the house. Roofs, and Pacific Northwest moss: water wide open, bleach wide open. That gives roughly a 50/50 mix, which lands near 6% out of 12.5% SH. That is what our moss needs out here. These are starting points, not gospel. Every job is different and the buildup is different. We keep a settings guide printed on the inside of the skid so nobody has to remember. One thing that catches new operators out: after you change a setting, it takes two to three minutes for the new mix to reach the gun. It has to work through the pump and then 200 ft of hose. Do not keep cranking the bleach because nothing changed in the first thirty seconds. The rinse step, which is the whole ballgame This is where mixers die. When you finish soft washing and switch to rinsing, here is the correct sequence: Turn the soap off — you do not want soap pulled into the line on a rinse Turn the three-way valve to water Leave the metering valve all the way open That last point confuses people. Opening it all the way is not turning your bleach on — you have already switched that leg to water. You want full flow through the block so it flushes properly. Here is why it matters. The old way of doing this was to just turn the bleach off and pull water in through the water valve. That does rinse your block, your pump, your hose and your gun — but it never brings water into the bleach leg of the mixer. So that leg sits full of concentrated SH until the next job. Our bleach out here is hot. We are often getting it at 13.5%, sometimes close to 14%. Leaving 14% sitting in a section of the mixer between jobs is how you get premature failure in exactly that part of the block, and it is why we build the rinse valve in rather than leaving it to technique. If your mixer does not have a dedicated rinse valve, that is what a soft wash bleach rinse valve adds. Yearly rebuild Check valves are a wear item. They typically go in one to two years, and the bleach side goes first — water and soap side check valves rarely give trouble. Rebuild the whole mixer about once a year: Pull all the parts and fittings off Scrub the old sealant and PTFE off with a soft bristle brush Reseal everything Reassemble with fresh check valves Do that annually and you eliminate most of the breakdowns crews see in the field. A blunt word about running this business If you are not mechanical and you do not want to turn a wrench, you are going to have to learn quickly. Bleach is corrosive. It kills parts. It works through seals. You will get leaks. That is not a defect in anybody's equipment, it is the nature of the chemical you have chosen to spray for a living. Preventative maintenance is what keeps you on jobs instead of in the shop. Parts and mixers Pro Mixer XL Custom 3/4 Soft Wash Mixer — the unit in this video Precision Pro metering valves and replacement parts Soft wash bleach rinse valve All soft wash mixers and parts Further reading How a Soft Wash Mixing System Actually Works 12V Soft Wash Pump Setup: Why Most of Them Die Early Choosing the Right Nozzles for Your 12V Soft Wash System Rebuilding yours and not sure what you need? Call the shop at 503-403-6185 (landline, no texts), Monday through Thursday, 8am to 4pm.