Hot Water or "Wet Steam" is NOT True Steam Cleaning!

Hot Water is NOT Steam!

repeat, repeat, repeat

There is a difference between a steam cleaner and a hot water pressure washer. I have been hearing lately the claims of some that they are the only ones in the area that have "steam cleaning" in their service line. Yes they use 248 degree to clean your home and businesses. While this claim is possible with specialized equipment with a standard 5+ gallon machine with a standard boiler 248 degrees is not reachable. 

Just because the knob says 248 on the pressure washer control knob it does not mean you are putting out that much hot water and for a long period of time. The best thing answer I have ever heard said if your burner never shut off you never got that hot.

Incoming water temps are considered “tepid”. Tepid is defined as moderately warm or lukewarm, it is generally considered to be between 60°F and 90°F. The temperature of the water will vary due to location and season.

Temperature rise is what we need to look at not the numbers on the knob. Some of the best boilers on the market have 130 degree rise with 5 to 8 gallons of output and 140 degrees at 4 gallons. If your incoming water is at 70* and you can raise it 130* that is 200* at 5 gallons output or 210* at 4 gallons. Not even steam yet, and a far cry form the touted 248 degrees of heat they are saying they use.

Of course all the above has a lot of variances; how much pressure you are using, length of hose will lose heat, the location your at above sea level. Yes water boils slower at higher altitudes than at lower levels. Another thing to consider is your hoses. Hoses are rated also to degree of use it seems that 250* is about top for high pressure "hot water hose" then the move is to steam hose higher temperature rating but less pressure. You are loosing heat through your hoses and equipment after the last connection on the burner. It is acting just like a radiator and is dissipating the heat. If you claim you're using 248* to clean that would be what is reaching the house, so in order to reach that amount of heat at point of impact you have to be running your burner at say  265* to 300* in-order to compensate for heat loss. I don't know of to many units that are not special built that can raise the water temp up 200* to 230* for use in the warmest weather to say nothing when it gets colder. False promises and misleading implications? Could be but I believe most don't understand how or what their equipment was designed to do or can do, or the phone operator taking their order. We have great vendors in our field use them and ask them questions about temperature rise and true steam.

Most "steam cleaners" or "vapor cleaners" are low pressure and have little water usage turning the state of water from liquid to a gas stage, something a pressure washer heating water can not do. You are only physical able to heat or actually raise the temperature level. It would stand to reason that water turns into a gas at the point of boiling so if your are truly heating water to 248* you would have steam only with no water run off. If you still have water you are not "steam cleaning" you are "hot water cleaning" and why would you wash a house with 248* water? The only benefit here would be rinsing with hot water not washing with hot water.

Using hot water for washing is not needed but for rinsing it would be a plus. After the soap and cleaners have been applied and aloud to work a hot water rinse would help to release the bond of these cleaners. Hot water would help to speed up the molecules and expand them in turn releasing there grip on the surface simple as breaking the surface tension with the hot water. Do we really want to release that surface tension when first applying the cleaner? Does not make scene. You must and need to understand what you're doing and how your equipment works, before you go off and make claims and promises that may not hold up. This may sound crash or harsh but as an industry we need to let others know what and how things work! Claiming you wash with 248* steam when what you have is incapable to do so, may sound good to a customer but will the true stated results show?

I use vapor or steam cleaning for disinfecting and cleaning where water runoff is an issue. Patio furniture, greasy motors, greasy equipment, motorcycles, stoves, shopping karts, playground equipment, kitchen and butchering items, while used mostly in the auto and manufacturing areas vapor cleaning is gaining a whole new life in the USA. Vapor cleaning in Europe and Australia has been going on and being refined for some time now during the '60's steam cleaning was loosing a battle to the pressure or power washer here in the States. Back then it seemed we had unlimited water, gasoline and diesel fuel all of which you would need to run a heated power washer, but in other countries they were already starting to conserve and look ahead. Vapor or steam cleaning is more efficient way to clean in a lot circumstances.

Both types of services are needed but there is a difference. True steam verse wet steam. Wet steam is a term used mostly to sell pressure washers. Most companies are now using a "heat rise" instead of "wet steam" to describe their units not the term "steam cleaner". This should help to show the difference and to clarify the terms more.

In steam a "dryness fraction" is used to quantify the terms if we use this we can now simply see what is steam cleaning and what is hot water washing. The amount of water within steam is what provides the term. If the output steam contains 10% water by mass, it's said to be 90% dry, or have a dryness fraction of 0.9. Steam dryness is important because it has a direct effect on the total amount of transferable energy contained within the steam (usually just latent heat), which affects heating efficiency and quality. An example, saturated steam (100% dry) contains 100% of the latent heat available at that pressure. Saturated water, which has no latent heat and therefore 0% dryness, will only contain sensible heat. If you see water pooling of running off you do not have steam you have the coined term "wet steam" very hot water still great for cleaning but not steam. The water contained in the steam is very important in cleaning.

Vapor Expansion is why steam cleaning works heating water up way over 214 degrees water boils at a temperature lower the 212°F boiling point of water at sea level.  A pressure washer operation the pump simply pushes hot or cold water out of a restrictive nozzle. The narrow passage through the nozzle increases the water's velocity and, consequently, its potential impact and cleaning power. In pressure washing, the pressure or restrictive nozzle is the last part of the machine the water flow passes through. In simpler terms the steam cleaner puts out steam more like a whistling tea kettle in stead of the pressure washer with super hot water similar to your kitchen faucet at full blast. The steam cleaner doesn't so much use steam to clean as it uses steam expansion to propel water at near its boiling point at a high velocity. The closer the steam cleaner's nozzle is to the surface to be cleaned, the higher the temperature and velocity of the water, the more effective the cleaning action. In addition to steam our vapor cleaners have a feature that we can add soap or cleaning solutions directly in to the cleaning stream the biggest advantage to this is that heat will help any soap or chemicals work more effectively, quicker and release and rince better this also reduces any "chemical runoff" to a smaller factor. The expanding and cooling of the water when the water passes through the  special nozzle puts the vapor additional pressurization and cannot remain a liquid at ambient temperature. The water cools itself to 212°F by vaporizing a portion of its volume. This is called "flashing to steam." Depending on the system, from 5 to 15 percent of the volume is unvaporized, cooling the remaining in liquid form. This steam vapor, with a properly designed steam cleaning nozzle, also propels the remaining water droplets. Unlike a pressure washer nozzle, where the restrictive orifice is the last thing the water passes through before reaching the atmosphere, the steam cleaning nozzle has an expansion nozzle placed past the pressure orifice. This directs the water vapor energy rather than allowing it to dissipate in all directions. When water vaporizes, it expands to almost 1500 times its former volume. This expansion, directed by the somewhat conical steam nozzle, adds velocity to the water droplets. So, not only does the expansion nozzle direct the steam cleaner's output, it serves as a sort of propulsion chamber. No simply the super heated water hits the air outside the small hole in the nozzle and becomes steam it more or less expands or flashes becoming like a small explosion and these small drops or hot water hit the surface and tumble and splat to chip a way the dirt or grease, it in the same process kills germs and bacteria. If this hot water is in a stream as that of a pressure wash no expanition and flash takes place just hot water and not at a tempature of 248* which is 118 degrees above the heat the burner can produce. Subtract the ambent temp of the incoming water you can see there is no way to produce steam.

OK if you have read this far my rant is over, on those who say they are preforming a service they are incapable of doing with the equipment they own. Remember knowledge is key and to grow this industry old myths and half true statements need to be updated and clarified. Those using the old terms need to help out by updating what the say or what they do. Steam is steam, not "wet steam" or very hot water there is a difference in how each unit is used and what they do, that is why they have different names and are used for different things.

Just cause the knob says 248* that does not mean you have true dry steam.