Total Cleaning Units:
what do you need to get the job done?
I have made mention the term cleaning units in this blog before, when I discussed how a power washer works. It is all of a sudden becoming a big selling point and a "key phase" in the power washing world. Though it has always been there to describe the over all effectiveness of the power washer it is taking on a whole new look. To recap total cleaning units is how effective a power washer works. A "CU" or cleaning unit is made up from how much power, psi and volume, gpm multiplying them together, that is pressure per square inch, psi times the gallons per minute, gpm. In a mathematical statement or sentence it would be psi x gpm = cu.
As of late I have seen more and more contractors and professionals using the idea of size to rank their washer and describing their how powerful the big rigs are. It is not how big or powerful a power washer is. It is having the right washer for the right job, it is just that simple. Increasing psi is not an option sometimes as we clean homes with alot of vinyl and wood siding we do not need more pressure which could cause damage. How do we get more "cu" to help us clean and work then? We can add more water or can we?
Also as discussed before the gallons of water being pumped thru the power washer make more difference in the total cleaning units than anything else. Lets look at this with and example.
pressure output is 3000 psi our gallon out put is 3 gpm
3000 x 3 = 9000 cleaning units
now let's change the gallons to 4
3000 psi x 4 gpm = 12000 cu
Now one of the most popular pumps in the market is a 6 gallon and an up and comer is the 8 gallon pump. let's just plug these numbers in and see what happens.
3000 psi x 6 gpm = 18000 cu
3000 psi x 8 gpm = 24000 cu
Just by adding more gallons thru the pump you can see that you have achieved a greater cleaning effect. This statement or mathematical sentence works the same with raising the psi. Let's have a look,
4000 psi x 3 gpm = 12000 cu
the same effective cleaning as a 3000 psi @ 4 gallon unit
4000 psi x 4 = 16000 cu
You can start to see that raising up the psi does not have as dramatic effect on the clean units. For us in the residential "house washing" field we don't want more pressure safe lower pressure is better for what we do. This is why we as power washers want to have more water running through the hose instead of more pressure. When you have a large pile of dirt what will move it better and faster? If you're throwing a cup of water on it at a time or a bucket of water at a time. We are using the same force to throw the water but the greater volume is moving the pile quicker, more water volume is better.
This now is the same with us the residential power washer we are using a safer lower pressure getting the job done faster, more effective, using less water and fuel for the motors. We are saving natural resources. Now comes in the big question if this is such a great thing why does not everyone use a large gallon output pumps? There are more factors that have to be added in.
1. Some residential areas have a smaller gallon output from there water supply.
2. Your house may be on a well system and the reserve tank is not that large.
3. The water supply has a flow problem when others use it too.
4. You will need a bigger motor to drive the larger volume pumps, and larger heater to heat that volume of water.
5. You will have a bigger footprint you rig will have to be larger.
We at Cleaned by Pete have run up against these problem in shared wells or in out laying areas. If you want to put out 6 to 8 gallons a minute you have to have that much water going in, simple physics.
Cleaned by Pete's biggest pump puts out 4.7 gallons per minute and we have found this works best for us and our cleaning methods and area needs. We found out that anything larger may be starved for water. This area's location and water supply, limits us from using anything larger in our residential cleaning. You can achieve using a larger gallon out put pump by adding in a buffer tank. A buffer tank is filled up before you start and holds the water in reserve. The tank holds the water waiting be used, so with the flow received from the hose tap or bib and your reserve water in in the storage tank,you can now use larger volume pumps. We will use a 35 gallon reserve tank in a situation with a older well or slow flow but we no longer haul a large water tank around. We ran into several situation where the pump could not keep up or run more than 50 feet of supply house the well pump could not push that much water even though it could fill a five gallon bucket in less than a minute, it could not deliver it any distance. We will use our little 35 gallon tank which will help us in this situation. If it takes more water than this we have a one 180 gallon tank that is fitted to one of our service trucks which we can use.
You have seen those big trailers carrying 100s of gallons of water on them. You fill them up and with the water supply and the reserve you now can run the bigger pumps with out a problem. Are you saying money I ran the numbers and found out no in our case we were using more gas hauling that tank around. We were using more gas pulling that trailer around. We had to pay out more to insure the trailer. We were not as manoeuvrable around in some areas. We had more ware and tear on our pump motors. We also were able to cut the cost of wear and tear on the outfit we had to pull the trailer around, and lastly you can not pull some trailers on certain roadways and areas in the Qzarks. It would be costing us more to use a bigger pump with the higher gallon output. It was costing us more to pull a trailer. We have chosen to use a bit smaller pump but it is in our case saving more gas and water helping the environment which we always try to do. It may take us a bit longer to do but with what we do it works better for us.
Should everyone use smaller units no should everyone stop pulling a trailer no. You need to know and to way-out all your options when finding what you're looking to wash and clean. The area Cleaned by Pete services water flow and water pressure dictates what we use. We do a lot of rural areas where the well and the home-owners pump also dictates what we can use. These remote areas also dictates what we can drive in and move about the property. Now would I use my units to clean the downtown parking garage? No I would want the largest pump, biggest motor, highest output unit I could find. Do I now want to use that same unit to wash my vinyl home? You will have to decide that call. Don't let others tell you they can do better than someone else just because they have the biggest baddest pressure washer that puts more psi and more gpm than anyone else. It dose help in certain situations but it is not the end to end all. Then do you want someone showing up with a too small pressure washer. Again having the right equipment and the right washer for each job, this is what we here at Cleaned by Pete try to do.
