Comments on: Electric Pressure Washer Convenience With Gas-Like Power

By: Steve Jones

Steve Jones — Mon, 01 Sep 2008 13:00:51 +0000

Hi, I have just bought a gas powered pressure washer from pressurewasherbitz.com.

I think they are far better to an electric powered washer as the GPM is much higher

By: mike

mike — Fri, 23 Nov 2007 00:23:53 +0000

This pressure washer sucks dick. DON’T BUY IT!!!!! i’ve been through two in a month, and returned it for a gas. Electric is a defnitite NO

By: Nate Bezanson

Nate Bezanson — Mon, 02 Jul 2007 03:06:29 +0000

Greg, you want a well pump. Or, you want to use the RV’s internal water pressurization system (which probably pumps air into a tank to force the water out) to feed the fan, which I guess will happily accept the 30 or 40 PSI that the RV system probably operates at.

Are you sure your trouble with the sump pump wasn’t just due to air in the lines? If the fan’s internal pump is a positive-displacement type, it might take a while to purge any air, and during that time you’d get spits and dribbles of water.

The trouble with using a bare well pump is that it’s not designed to run at 100% duty cycle against a “brick wall” sort of load like that. You want an expansion tank that it can pressurize, then switch off, and switch back on when the pressure in the tank drops again. That’s bulky and expensive, and I’m still pretty sure it’s all duplicated in the RV’s systems. See if the sink faucet has an aerator thread that you could adapt. (Check a garden supply for a sink-threaded “watering hose”.)

By: Greg

Greg — Sun, 01 Jul 2007 20:59:00 +0000

Don’t know it there are any experts out there for this wierd question but here goes.

I have one of those patio-type misting fans - which you hook up to a house-fed garden hose (at 60 psi or so) and it sprays a mist in front of the fan blades - works good at cooling things down. Because it emits a fine mist, the output is something like 1-2 GPM at 60-80 psi

I want to use this fan at the NASCAR race in Daytona next weekend - in the infield. We have access to electric power (an RV) but no water.

Thinking I can find a way to make this work, I hooked dropped an electric sump pump in a bucket of water with a short garden hose to the fan - it spit out a little water - but not nearly enough. Those sump pumps emit 1,100 (or more) GPM at relatively low pressure.

Then I got the bright idea of trying the electric Karchner pressure washer I have in the shed. It is rated at 1400 psi. I filled a 3 foot length of garden hose with water, hooked it up to the unit where the garden hose (under pressure) would normally be fitted, stuck the other end of the hose in a bucked of water, and screwed another short length of garden hose to the output position of the pressure washer in lieu of the high pressure hose (it’s threaded the same).

I hit the switch and it started pumping a small amount of water - with a lot of pressure behind it (if I used my thumb to cover the hose it would NOT stop the water flow). So I hooked it up to the fan - and it worked GREAT for a few seconds and then blew the small diameter hose to the fan. I then hooked up a 200psi water pressure gauge to the output garden hose, which quickly pegged at 200psi and then the garden hose blew.

I’m thinking it I can find a way to bleed off some pressure this unit will do what I need it to do - dispense a few GPM per hour at 80 psi or so.

Thoughts???? Thanks

By: Chris Ball

Chris Ball — Fri, 29 Jun 2007 18:18:35 +0000

I agree with everyone else, the amount of water that leaves the end of the pump is probably vanishingly small. Also I’m pretty dubious about the two hp rating. My rule of thumb is that you get 1 to 1.5hp per 15amp circuit. One if you are using cheap equipment or you want to have the lights on while you use it and 1.5 if you have a completely dedicated circuit.

Here’s a couple links so you can quickly figure out what you should be able to pull with an average motor:
1.) This will give you the efficiency by hp of induction motors (universal motors should be similar). These numbers seem a touch pessimistic but aren’t too far out sounding.
http://www.actionmachinery.com/hp-eff.htm
Alternately you can go to baldor’s site and just pick a motor that matches you application and it will tell you all the specs which should be a lot more accurate than the other table, if a little bit more work.
http://www.baldor.com/products/default.asp

2.) This will do the math for you, give it your voltage and current at the plug and the efficiency from the other table and out pops your hp.
http://www.dxpe.com/gadgets/horsepower.asp

3.) Finally here is a good motor primer from somebody that probably knows considerably more about these things than me.
http://www.faqs.org/faqs/woodworking/motors/

Finally do keep in mind that there is an initial surge current when the motor starts that is several times what is calculated above fortunately it comes and goes before the breaker can pop so everything works out, usually.

By: Robert

Robert — Fri, 29 Jun 2007 14:19:17 +0000

“so wouldn’t the GPM be the same for a gas or electric powered washer as they both connect to your water hose?”

Garden hoses deliver far more GPM than any portable washer can use. Pressure washers have positive displacement pumps. GPM is a function of pump displacement and RPM. It takes a lot of power to put out 4 GPM at 4000 PSI like my 13 HP washer.
By the way - 1300 PSI is fine for deck washing, too much pressure causes the wood to “fuzz”.

By: Kyle

Kyle — Fri, 29 Jun 2007 13:25:38 +0000

soooo, has anyone actually used this? Or is this all just speculation?

By: jgb

jgb — Fri, 29 Jun 2007 12:48:54 +0000

Had one of these plastic electric pressure washers. After a couple of years the pump quit. Took it apart and a plastic part was broken in what was an almost completely plastic pump. The part was so expensive it didn’t make sense for me to fix it, so I saved up and got a Karcher gasoline model. Big lots routinely has refurb Karchers with Honda engines at a good price.

By: ivan

ivan — Fri, 29 Jun 2007 12:45:02 +0000

Reading the other comments, so wouldn’t the GPM be the same for a gas or electric powered washer as they both connect to your water hose?
I mean even gas powered tools are not sucking more water from the system, or am I missing something.

A couple years ago I bought a cheap 1300 PSI from the local improvement store and it has served its purpose as cleaning the deck, siding, car etc.

By: Douglas Kwan

Douglas Kwan — Fri, 29 Jun 2007 03:05:05 +0000

yea i was going to mention you have to also watch GPM when looking at pressure washers

By: Robert

Robert — Fri, 29 Jun 2007 02:34:27 +0000

When comparing pressure washers, two numbers matter - PSI and GPM. Pressure determines what the machine is capable of removing, and gallons per minute determines how fast it will work. The reason there ain’t no powerful plug in electric pressure washers is because the power is limited by the 20 amp circuit in your home. It may be possible to have a high pressure on electric power, but the GPM will be so low that you will get bored and give up long before you get your driveway clean.
Ther may be a place for a high pressure, low volume washer, but if you need to wash your driveway, house, or deck, either rent or buy a 9 to 13 HP gas powered rig. Most equipment rental stores have them, and big box stores and online sites have 13 HP direct drive washers for around $1000.