5 GPM vs. 8 GPM

I forgot to mention, I only use 3/8" hose with both the 5.5gpm and 8gpm machines for house washing, for concrete cleaning I will use the 1/2" hose.

You are losing 300psi for every 100' when using 3/8" hose with 8gpm vs. about 40psi every 100' when using the 1/2" hose and 8gpm.
 
good call Chris.

GPM is WorkSpeed, and comparing hose restriction to convenience is personal preference..
Chris chooses for the jobsite, based on "relative WorkSpeed"

I suggest 8gpm at 3600psi
.. or 7gpm at 4000psi
.. .. 20" heater
 
I bought a hot water 5 GPM Landa skid unit when I started. I do residential and smaller sized commercial projects. I also have a 4 GPM cold water portable unit. My next one will undoubtably be an 8 GPM hot water so I can pick up larger commercial projects and rinse faster. And if I had to choose between hot water 5 GPM and cold 8 GPM I'd go with the extra GPM.
 
810f250 said:
My 0.02 cents, with some of the newer products available today and the little experience I have.

If I had to get a hot water skid today I suggest it be a 7 to 6 gpm pump with a 4000 psi and over head rating. Over size the gas engine if possible, or using at least this HP formula for pump ((gpm x psi )/1460) x 1.5, .... a 20" minimum coil , 120 volt burner (really just for the added convenience to plug in small tools or run lights, but if 12 volt was selected ensure the largest amp charging/alternator spec of the engine)
Click to expand...

Sirocco Jerry said:
good call Chris.

GPM is WorkSpeed, and comparing hose restriction to convenience is personal preference..
Chris chooses for the jobsite, based on "relative WorkSpeed"

I suggest 8gpm at 3600psi
.. or 7gpm at 4000psi
.. .. 20" heater
Click to expand...


Whats your opinion on the HP calculation quoted? (I know some engines are/can be sized smaller)

I think the 7gpm at 4000psi is a sweet combo compromise.


The only other single unit gas driven machine combo that can may out perform the 7 @ 4000 is........... 10gpm @ 4000 IMO, but the coil I recommend be 3/4" , and the hose size based on the job pressure requirement.
 
Christopher said:
You are losing 300psi for every 100' when using 3/8" hose with 8gpm vs. about 40psi every 100' when using the 1/2" hose and 8gpm.
Click to expand...

Haven't done a psi check on our trailers since the Summer, but now you've got me thinking about it Chris.

Last time I checked ours, we were only getting a 300 psi drop with 200' of hose with no down streamer based on a machine that is 3000 psi @ 8 gpm. I wonder what the gpm loss is?
 
810f250 said:
Whats your opinion on the HP calculation quoted?
(I know some engines are/can be sized smaller)
.. I think the 7gpm at 4000psi is a sweet combo compromise.

The only other single unit gas driven machine combo that can may out perform the 7 @ 4000 is.. 10gpm @ 4000 IMO
but the coil I recommend be 3/4" , and the hose size based on the job pressure requirement.
Click to expand...

I tend to lean toward "most affordable" vs the cheapest deal at "point of sale". (..think about it.)
..I mean.. I'm going to try to sell real performance for the dollar, instead of "competition to the mass-produced" systems..
As rthe "mass produced systems are meant to be profitable to the mfr, not specifically a good value an YOUR JOBSITE.
..See, common sense will win the customer long-term, NOT the "best salesman" ..in the 3rd year of a recession. Eh?
I don't make as much as big mfr's, but I also don't leave a vapor-trail of rock-kickers behind.

AaaaaannyWaaaay..
here's the point..
6.5gpm @ 4000 psi = 18.2HpCont. .. we can do with a 23hp "rated engine @79%, without the "price-jump" to a Big V-twin.
That's running the motor at "full tilt".. but it's a doable system for performance value.
..Ask for a bigger motor, and we'll do that, I'm just sayin' value in performance is right there.
..using a 12vDC burner in 18" heater, or upgrade to 20" heater, etc..

But.. if you don't mind spending on a Big V-twin,
Let's go all the way.. a 35hp engine at 80% for 28HpC can do 4000 psi to 10gpm.
If you want a cooler running motor.. use the 40Hp Kohler.. nuf said.

Now, I want to address the 3/4" coil idea..
First I want to say.. based on the way "bean-counting" big mfr's think..
I can almost guarantee the shorter length of 3/4" coil fits in the heater shell at a lower cost than the longer length of 1/2" coil.
The "big mfrs" push for profitability, NOT "Long-Term value".
BUT.. there IS an intelligent angle for FLOW..
Less flow restriction has already been "topic of the month" in here (Except the drama threads. LOL)
10gpm is going to flow easier through the 3/4" pipe coil, but the flow restriction in 1/2"id hose is WAY more an issue than 1/2"id pipe.

Also.. one man, (that is not 6'6" and weighing in at 275+) is not going to wield the hefty sword of 10gpm at 4000 psi
.. for an entire 8 hour job, day after day..
you're probably going to hire some help. and split the flow for 2ea. 5gpm wands,
..or 3 to 4gpm to a turbo nozzle, and 6 to7gpm to a Vacuuming surface cleaner.. Kickin' a$$ and takin' names.
Ooops.. but with one big heater, you're at risk of over-heating quickly,
.. with only one wand open, and the other at rest (or dude BS'n on the cell phone).
K now wait a minute.. 3/4" coil, at risk of overheating, and the 3/4" coil has LESS a pressure rating on a good day than the 1/2" coils.
I hate what bean-counters have done to this industry, so I'l going to say it..
There might be an ulterior motive (called "expensive parts sales") in making a coil which is MORE sensitive to "operator abuse"
..which will NOT be covered under the warranty.. guartanteed.

How does Jerry solve this problem??
.. You really need 4 to 6gpm at each wand, for the average Helper-dude.. which does NOT weigh 250 nor is he 6ft.6.
..and 1/2" coils will LAST LONGER,
..and 2 smaller heaters are better than 1 big one, for safety and heat control..
Let's say you're spending an extra $1000 to do this..
if you DON'T blow a $2000 coil in the next 10 years, NObody gets hurt, you don't blow as many hoses, and you just MADE money.

And.. I personally don't like the results of spending $2000 on a 10gpm pump rated barely 3600psi
..that will eat seals every 12-24 months because you will tank-feed it "barely".
When using a pair of $800 pumps rated for a full 4000 psi and 7gpm each will go a few years at 5gpm
..and the seal kits are 1/3 the cost..
I'm saying dual pumps, and dual heaters is the BEST performing combination you will get for your money.
..but hey, that's just my opinion..
with 40 years experience in bullet-proofing machinery, 30 years studying reliability in THIS industry,
and aiming at Long-Term relationships with my customers.
..It's your money, YOU decide.

SO far, my favorite system.. of all that we've built so far..
35hp 4cyl Diesel engine, "sound-proofed",
with dual 7gpm 4000 psi pumps, running 6gpm each.
..and Dual 20" heaters for amazing, controllable, reliable heat.
..and yes, they have 12vDC burners with that huge 45 amp alternator to keep 'em reliable.
 
Last edited:
I didn't really mean to "hijack" this tread,
So except for the 6 vs. 8gpm and "generic" questions..
please e-mail me about the more intimate equipment questions.
:{)
 
Sirocco Jerry said:
I didn't really mean to "hijack" this tread,
So except for the 6 vs. 8gpm and "generic" questions..
please e-mail me about the more intimate equipment questions.
:{)
Click to expand...

Jerry, your posts are always interesting and informative. I like the way you think in terms of long term low cost. One day when I can afford any machine I want, one of yours will probably be my top choice. Right now though, on a budget of $3500-$4000, I have to stick with what I can find used.

The being a small guy holding that wand all day thing may be a factor in didn't think of though. Is 3000 PSI at 8 GPM going to be hard for a 6 foot 142 pound guy to deal with all day? I definitely wouldn't want to deal with 4000 at 10 GPM.
 
Josh come up with a couple hundred more and i will send you back to fla with all the washer you will ever need no matter what you wash.30 hp Kolhlor 11gpms@3000 psi udor pump and Hotbox with 258 feet of good ole USA steel 1/2 inch coil.The unit has less than 800 hours.
 
JDhomeservices said:
Jerry, your posts are always interesting and informative.
I like the way you think in terms of long term low cost.
One day when I can afford any machine I want, one of yours will probably be my top choice.
Right now though, on a budget of $3500-$4000, I have to stick with what I can find used.

The being a small guy holding that wand all day thing may be a factor in didn't think of though.
Is 3000 PSI at 8 GPM going to be hard for a 6 foot 142 pound guy to deal with all day?
I definitely wouldn't want to deal with 4000 at 10 GPM.
Click to expand...

LOL..
.. in this business.. you'll be putting on about 10lbs/year just in your shoulders..
.. welcome to a fulltime upper-body workout..
Just be sure to wear your ear plugs and as you're muscling around the equipment and pails..
Don't "lift and twist" at the same time.
.. "Tough guys" are the first to get back problems.
 
Thanks for your response Jerry, great getting the manufacturer thinking.

When I initially proposed 10gpm at 4000psi , I was thinking the use of dual pumps, with one coil, I heard and know about the 3/4" sch 80 coil pressure rating/reliability, and some manufactures cheating on the length.

Controls will definitely have to be redundant on 3/4 coil and independent dual guns. I have seen what can happen when the trigger is released with reduced flow in heating coil, and then resume spraying (possible overheat/superheat condition)

Thinking 2 coils one engine driving dual pumper is almost two independent units.

I was thinking the biggest single unit would be one coil, single engine, dual pumps.

I really dont think 10 gpm @ 3500 to 4000psi on the wand is easy for anyone, have issues with 8 at 3200 and 1/2"

The thought with 10 gpm is similar to what you mentioned, I was thinking 6gpm in the surface cleaner at 24" 3 bar and one man behind gum popin and cutting in with 4 gpm....like you mentioned kicking butt
 
Many variations are available..
We specialize in custom systems, and I prefer you contact me by e-mail, or phone.
There's a LOT to know about the available tools, multifunctionality,
and customizing for YOUR jobsite.
 
We have a 10+GPM @3600psi PW & it's a beast. Great for what we use it for but wouldn't recommend it for a 1 man operation dealing with a pump that size.

Tough decision on what to go with between a 5gpm vs 8gpm PW. If you find a good enough deal I'd go with the 8gpm hot water PW. Or at least cold and save for a hot box. Check out Hal's deal above.

Just make sure you have a water tank of at least 100 gallons to keep that machine well fed and also use the water tank of course to help you set up the machine to run in bypass when not squeezing the wand so the pump doesn't over heat.

The beauty of an 8gpm PW for house washes is you can change the tip sizes so you have less pressure and alot of water volume to increase your washing ability in a shorter amount of time.

If you really want to roll the Dice buy Jerry's diesel setup. That motor will last forever and it will over time pay for itself over and over again.

You gotta love the choices you have.
 
Clean County PW said:
We have a 10+GPM @3600psi PW & it's a beast. Great for what we use it for but wouldn't recommend it for a 1 man operation dealing with a pump that size.

Tough decision on what to go with between a 5gpm vs 8gpm PW. If you find a good enough deal I'd go with the 8gpm hot water PW. Or at least cold and save for a hot box. Check out Hal's deal above.

Just make sure you have a water tank of at least 100 gallons to keep that machine well fed and also use the water tank of course to help you set up the machine to run in bypass when not squeezing the wand so the pump doesn't over heat.

The beauty of an 8gpm PW for house washes is you can change the tip sizes so you have less pressure and alot of water volume to increase your washing ability in a shorter amount of time.

If you really want to roll the Dice buy Jerry's diesel setup. That motor will last forever and it will over time pay for itself over and over again.

You gotta love the choices you have.
Click to expand...

John did you ever want/wish you had 4000 psi head pressure for the long hose runs?
 
810f250 said:
John did you ever want/wish you had 4000 psi head pressure for the long hose runs?
Click to expand...

I had that Nigel and I Pretty much gave it away here to one of the guys on PWI. I didn't realize tue Pump cost over $4000. It was a UDOR pump rated at 11gpm @4500psi. It weighed a aprox 100lbs. I sold it with a cold water diesel setup for around $4500.

I wish I never sold that pump.

As for the 10.5 GPM pump I have now it's also a UDOR under the Envirospec name. That pump is excellent but nothing like that above UDOR. We use this machine for the big Hydrotek surface machine for residential and commercial and also for my Swabby when doing garages. I have the unloader tighten down a little more where we are squeezing 3800 psi @ the pump. It's 200 psi above rating but it come out around 3200-3400 @ the end of the usual hose length we use it at.
I love this pump. If you ever open up a UDOR you wil see it's much stronger then my most used pump which are GP tsf2021 rated at 8.5 GPM @3600psi.
 
You must log in or register to reply here.
Back
Top