What is the big deal between cold water and hot water pressure washers? I would have thought u could get both in one washer. I have been eyeing this one washer at Home Depot, it is a 3600psi washer, what do u guys think? Again, i will be going after commercial and residential properties.
Pressure Washers
- Thread starter LJBOYCE
- Start date
Michael
New member
The short answer is it depends....what you are cleaning, how often, where, available water supply, soap etcetera.
The long answer is complicated by the short. High pressure does not make a good cleaner. High pressure will cause metal to dent, paint to strip, windows to break, deck lumber to 'fur', toes to be cut off etcetera.
All hot water washers can be used as cold water units by not turning on the burner.
In every case belt-drive will outlast direct-drive by a significant margin. Belt also draws both water and soap much better than direct.
Flow is ALWAYS more important and of value than pressure.
More Flow = Less Time (washing/rinsing) = More (potential) $$
Horsepower is directly related to flow not pressure. Impact force in pounds for similar "Cleaning Unit" washers is as follows:
1 @ 4000 = 3.34#
2 @ 2000 = 4.73#
4 @ 1000 = 6.69#
As you can see having 4 times the flow and 1/4 the pressure gives twice the impact force. Also the cost of the components required (not neccessarily used) on units >3500 PSI is significantly more than on units <3500 PSI.
Or to put it another way....pressure = speed.
So which do you want to catch thrown at you at 5 MPH (8 kph); a baseball or a bowling ball? Now you know the importance of flow.
This also brings up the warranty and who covers it. Read the sign at Home Depot and you will find they do NOT warrant the unit, do NOT return your money and actually put the onus on the manufacturer to provide that. They do NOT stock parts. Do NOT provide training on safe operation and simple maintenance procedures. As a matter of fact they will thank you for your money and see you out the door.
For a few dollars more you can go to a local professional pressure washer dealer and get a machine that will do the jobs you plan on completing. They will be a source of soap, service, training and advice. They will honour warranty and possibly provide a loaner if needed.
Hope this helps? Cheers.
The long answer is complicated by the short. High pressure does not make a good cleaner. High pressure will cause metal to dent, paint to strip, windows to break, deck lumber to 'fur', toes to be cut off etcetera.
All hot water washers can be used as cold water units by not turning on the burner.
In every case belt-drive will outlast direct-drive by a significant margin. Belt also draws both water and soap much better than direct.
Flow is ALWAYS more important and of value than pressure.
More Flow = Less Time (washing/rinsing) = More (potential) $$
Horsepower is directly related to flow not pressure. Impact force in pounds for similar "Cleaning Unit" washers is as follows:
1 @ 4000 = 3.34#
2 @ 2000 = 4.73#
4 @ 1000 = 6.69#
As you can see having 4 times the flow and 1/4 the pressure gives twice the impact force. Also the cost of the components required (not neccessarily used) on units >3500 PSI is significantly more than on units <3500 PSI.
Or to put it another way....pressure = speed.
So which do you want to catch thrown at you at 5 MPH (8 kph); a baseball or a bowling ball? Now you know the importance of flow.
This also brings up the warranty and who covers it. Read the sign at Home Depot and you will find they do NOT warrant the unit, do NOT return your money and actually put the onus on the manufacturer to provide that. They do NOT stock parts. Do NOT provide training on safe operation and simple maintenance procedures. As a matter of fact they will thank you for your money and see you out the door.
For a few dollars more you can go to a local professional pressure washer dealer and get a machine that will do the jobs you plan on completing. They will be a source of soap, service, training and advice. They will honour warranty and possibly provide a loaner if needed.
Hope this helps? Cheers.
Hotwaterwizard
Hotsy Service Tech
Tell me Michael, How do you come up with the impact force in pounds. This is a great tool. What is the formula?
By the way I am an Epps Distributor in Fresno and Stockton California.
Steam Cleaners Inc Website
By the way I am an Epps Distributor in Fresno and Stockton California.
Steam Cleaners Inc Website
Last edited:
Michael
New member
Always willing to credit a greater mind than mine 
The formula is available from http://www.giantpumps.com/nozzle_chart.html
Another excellent source for formulae is http://www.arnorthamerica.com/handyformulas.html
Reaction force, pounds = [Flow x Square root of pressure] / 18.92
The formula is available from http://www.giantpumps.com/nozzle_chart.html
Another excellent source for formulae is http://www.arnorthamerica.com/handyformulas.html
Reaction force, pounds = [Flow x Square root of pressure] / 18.92
Hotwaterwizard
Hotsy Service Tech
John, actually I have that chart, or something similar. The second chart gives the % impact AT 12 INCHES. My question, how does impact change as you move closer to the surface?
Maybe there is a way to approximate. Using the 1st table, a 25 degree nozzle at 12 inches, one calculates a spray coverage of 5.3 inches. The second table would give a % theor impact of 18%.
Now assume that one operates at a 2" distance. Using chart I, the coverage is .9". I would be forcing the same flow onto the shorter pattern, so the impact will increase - but by how much?
Consider the ratio 5.3/.9 (which is roughly 6). Does psi increase by a factor of 6 in this case? If so, then the impact goes up proportionally, i.e. by 6X.
John, the essential factor seems to be "how does psi change as function of spray pattern?".
Your thoughts??
Maybe there is a way to approximate. Using the 1st table, a 25 degree nozzle at 12 inches, one calculates a spray coverage of 5.3 inches. The second table would give a % theor impact of 18%.
Now assume that one operates at a 2" distance. Using chart I, the coverage is .9". I would be forcing the same flow onto the shorter pattern, so the impact will increase - but by how much?
Consider the ratio 5.3/.9 (which is roughly 6). Does psi increase by a factor of 6 in this case? If so, then the impact goes up proportionally, i.e. by 6X.
John, the essential factor seems to be "how does psi change as function of spray pattern?".
Your thoughts??
Z
Zippo
Guest
Who cares??? Either the surface is clean or it isn't. Your client sure the hell doesn't care what the physics are, he's paying to have the area cleaned, not get a lesson in quantum physics. And you shouldn't care, 'cause it don't much matter!
Mike Hughes
Former Board Administrator
Keep it clean zippo.......dont make me have to edit you again.
Hotwaterwizard
Hotsy Service Tech
This is not too technical but, try this: Take the figures from 12 inches away and multiply by 2 this approximates the impact at 6 inches, multiply by 2 again and it gives aproximate at 3 inches.
I'AM STARTING TO AGREA WITH ZIPPO!
LETS JUST SAY THE MORE GPM AND THE MORE PSI THE BETTER!TO A POINT! AT 40,000 PSI AND 15 GPM YOU CAN CUT BRIDGES IN HALF!
BUT FOR EVERY 20 DEGREE YOU RAISE THE TEMP, YOU DOUBLE THE CLEANING POWER!
PLUS CHEMICALS , NOW WITH THE RIGHT CHEMICAL YOU CAN ALSO DOUBLE THE CLEANING POWER OR MORE!
THE CHOICE IS SIMPLE , USE $100 WORTH OF CHEMICALS WITH A COLD WATER WASHER OR $20 WITH A HOT WATER WASHER!
YOUR SAVINGS IS ABOUT $70 WITH A HOT WATER WASHER ON A $250 TO A $350 JOB!
OF COURSE HOT WATER 48" AWAY FROM THE SURFACE , DOSE NOTHING , YOU LOSE ALL YOUR HEAT.
THAT WHY YOU NEED A GOOD CHEMICAL IN MOST CASES! BUT NOT ALWAYS!
LOOK AT THIS TANK I DID I WAS SPRAYING SOAP AROUND THE SIDE OF THE TANKS AS FAR AS I COULD EACH WAY AND AS HIGH AS I COULD! BUT I USED A GOOD CHEMICAL!
LETS JUST SAY THE MORE GPM AND THE MORE PSI THE BETTER!TO A POINT! AT 40,000 PSI AND 15 GPM YOU CAN CUT BRIDGES IN HALF!
BUT FOR EVERY 20 DEGREE YOU RAISE THE TEMP, YOU DOUBLE THE CLEANING POWER!
PLUS CHEMICALS , NOW WITH THE RIGHT CHEMICAL YOU CAN ALSO DOUBLE THE CLEANING POWER OR MORE!
THE CHOICE IS SIMPLE , USE $100 WORTH OF CHEMICALS WITH A COLD WATER WASHER OR $20 WITH A HOT WATER WASHER!
YOUR SAVINGS IS ABOUT $70 WITH A HOT WATER WASHER ON A $250 TO A $350 JOB!
OF COURSE HOT WATER 48" AWAY FROM THE SURFACE , DOSE NOTHING , YOU LOSE ALL YOUR HEAT.
THAT WHY YOU NEED A GOOD CHEMICAL IN MOST CASES! BUT NOT ALWAYS!
LOOK AT THIS TANK I DID I WAS SPRAYING SOAP AROUND THE SIDE OF THE TANKS AS FAR AS I COULD EACH WAY AND AS HIGH AS I COULD! BUT I USED A GOOD CHEMICAL!
