So if i am looking at a 5GPM 4000PSI pressure pro machine- how much of an issue would you think I would have with customers water pressure at their hose bib? I work with a mix (city water/well water) customers. I guess I am asking since I never have that issue with my current smaller 3500psi 3GPM unit…
Thoughts? Is there a thresh hold where you say at a certain GPM a buffer tank is absolutely necessary?
Unless you are on strong city water 100% of the time,You absolutely need a buffer tank for anything over 4gpm, Otherwise you are risking blowing up your pump if you run into low source water pressure.
In some areas you may even need a buffer tank for 4gpm.
You’ll need a buffer tank. I have a 5.6gpm machine and I run into water pressure issues with some regularity. I have a 100 gallon buffer tank.
I just threw together a couple new machines. After one big job these will serve as backups, so they are built with simplicity and price in mind, not durability, but it might not be a bad way to go for a window guy who does little power washing on the side. Under $900 per unit. 15 hp lifan engine, 4.5gpm AR RKV4.5g40 pump (5 and 5.5 gpm versions also available if you are willing to sacrifice a little pressure). Base plate, some fittings and unloader and you are good to go. With a 5 nozzle, these will push over 3200 psi. I have a siamese kit so I can pair them up and run 9gpm over 3000 psi for under $1800 total.
This is a direct drive triplex pump. Not as durable but cheaper and way easier to set up than belt or gear. Also, fewer moving parts and things to get loose or leak.
I also built my own machine based on price and simplicity, bought a 13hp honda copy for about $330, then a 4350psi 23L /min pump for $250 direct drive,
My overall thoughts were should I spend the $1500 on the Italian pump that will last 5 years + but needs to be professionally services twice a year each servicing was $180 so $360 to maintain the Italian pump vs $250 to replace the cheap pump, so what did i do bought a spare pump so when this 1 does bite the bullet its a few minutes for me to change pumps over. So far have used this machine for about 18months without any problems still on initial pump.
I have to say I have to thank who ever linked that video for the past 2 years I have been down streaming from the handle with an auxiliary hose to a 20L bucket as I was informed that after a certain amount of hose down streaming would not work, I was always attempting to use the in pump down streamer however with a hose longer than 7 meters that will not suck soap so i bought a external down streamer and placed it on the handle assuming it was due to the length of hose preventing the soap from being pulled thru, since i have started to equip my trailer i did it the other way around and it works so well i should save about 25-30% time now having my mix in the trailer and not having to drag it around every 15 meters, and have the hoses getting tangled.
Hmm I’m thinking what your saying you were doing is like Xjettimg were the solutikn hose is connected to the gun. Except you used a downstream injector .
With down streaming you could put the injector anywhere after the pump . Usually at the reel is the most desired . Am you could set your solution bucket up right ther
I think with down streaming you could draw well with up to 150 feet of hose. I never really attempted nor needed more than 150.
The video your talking about is the one I put up yes?
Not sure how many feet equal a meter
We run the injector between hose connections 100’ from gun. Minimal movement of mix bucket on most jobs, but you don’t have to wait long for the mix to clear the line when you switch to rinsing. It’s a good compromise that I’ve found works well.
the downstream injector was at the base of the gun where the hose attaches.
1 meter = 3.3 feet
Is it true that a Pressure-Pro 400PSI 4GPM direct drive cat pump unit will not draw from a buffer tank?
i think so. from what i understand, direct drive pumps don’t create enough suction to pull from a tank. never tried it personally, but i’ve heard other people i respect say that.
Belt drives run at about 1/2 the RPM of a direct drive. This doubles the piston stroke and increases the suction at the inlet. Increased suction = increased hydrostatic lift. Check the pump specs, you'll see the difference for DD vs belt drive versions.
In some applications, this additional lift may make the difference between being able to use a non-pressure feed like a tank. Whether yours works or not depends on the lift height, seal condition, hose size, hose length, # of bends, degree of bends, air leakage, etc. This is why you have some people saying you cannot pull from a tank, while others say it works just fine.
This is not from me i copy an pasted this from a thread i read awhile back . 
im not ths smart lol
Some more …
The supply line on the tank may be lower than your pump, but you only need the water level in the tank to be higer than the inlet on the pump, then it should draw. Once it starts to draw you can even let the water level run below the supply on most pumps. Try it. There is a five inch difference between my tank outlet and my pump inlet. As long as I start out with the water level in the tank higer than the pump, then it works fine. My pump is also direct drive.
No, it wouldn’t be considered direct drive. It’s still reducing the rpm of the pump, giving the same benefits of a belt drive mentioned in @Majestic66’s post. And some will argue that gear reduction is even better than belt driven. I don’t have enough experience to say either way.
So I purchased the pressure pro 4gpm 4000psi unit and going to set up the plumbing tomorrow. Anyone have a pic or info on how they got the feed hose from the buffer tank to the pump? I was thinking 1" hose but would like a few examples of possible…
1" is the way to go.
Here i got this from Bob @ pressure tek a while back hope this helps Just prnt it it will be easier to read 
frIMG_20160522_0004.pdf (1.2 MB)om .
This helps a lot, thanks!!
We have a cold water 2500psi 5.5gpm from powerwash and recently Purchased a new Landa hot water skid we installed into a new 6x12 enclosed tandem trailer. We decided to go with hot water 3500 psi 4.7gpm. We love having both especially after landing some commercial last year we really needed the hot skid unit.
Awesome machine and set up!
So for an update, I did buy this machine last year. Works awesome, and way, way faster than the 3.5gpm machine I had been using.
