# Problem with Jetter Pulling Through Line



## noefexus (Jun 9, 2011)

Hi All,

I have a trailer mounted jetter with a 34 HP Kohler motor and a General TS2021 PUMP (Max 8.5gpm @ 3600 psi. I run a 300' 3/8" hose with a variety of different nozzles, mostly cheapies (ram, flush, spinner, lazer). I would like to clean 4-6" lines. I am having severe issues with this producing a higher psi than 3,400 @ approximately 3,500 rpm, and the hose is not pulling through as fast as it should. Could this be caused by the nozzles or is it an undersized pump for the motor?

First of all, is this pump undersized for the motor? A simple calculation of cleaning units (CU) shows: 34HP X 1100(for an internal combustion engine)= 37,400 CU. In order to calculate the CU of a pump; GPM X PSI=CU, any combination adding up the CU of the motor should work with that motor. 
+Currently, the following is being used; 8.5 X 3,600= 30,600 CU, which is less than the 37,400 the motor is capable of producing. 

What do you think, is it the nozzles or the pump?

I was heavily considering ordering a 3/8" Warthog CT, but want to get some other opinions first. Thanks


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## SewerRat (Feb 26, 2011)

I'm not quite following. Are you saying that you are reaching full psi before the engine is at full rpms? If so, your nozzle orifices are too small. Or, are you not achieving full pressure at full rpm? That would mean your nozzles are drilled a bit on the large side. Explain a little further please and the good ole' boys on here will try to help.


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## noefexus (Jun 9, 2011)

The engine is running at full bore and it is only achieving 3,400 psi, with the "ram" nozzle. It is achieving even less psi with the other nozzles we have. For a fairly large unit, it just isn't pulling very well through 4" pipes.


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## SewerRat (Feb 26, 2011)

If it changes with nozzle selection it's a nozzle issue. You could run 1000 hp on that pump which would be way overkill but the pump itself should perform as advertised as long as it's turning at the rated rpm.

At 8 gpm you will lose approximately 300 psi per 100' of 3/8" hose according to various charts on the net. Your pump is rated 8.5 at 3600 psi at 3400 rpm. Since you are over 8 gpm lets bump the pressure friction loss up a bit and say since you are running 300' of hose you lose 1000 psi in the length of your hose. Call Aqua mole and have them drill you a custom set of nozzles for 8.25 gpm at 2600 psi. Have them drill a flatter 30 degree rear pattern for more propulsion on your ram nozzle.


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## noefexus (Jun 9, 2011)

OK, will try that. Should I change to a 1/2" hose?


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## Sewer Saint (May 5, 2012)

Sewer Rat is dead on right here.

I would say your engine is underpowered but then again I am addicted to Harben jetters and massive psi.

If you are running 4" you are fine with what you have but at 6" and especially at 8" go with the 1/2" line.

The smaller and more flexable lines can turn around in 8" and you do not want that.


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## gear junkie (Jun 20, 2008)

Your pump is only 5.6 gpm at 3500 psi and seriously undersized for your engine but it's not hurting anything. Where did you get the 8.5 gpm? If you decide to keep the current pump/engine setup I would recommend.... 

-using 1/4 hose
-get a SIZED drilled set of nozzles from aqua mole. 
-use a root ranger to cut roots

ideal setup.....
-get a 4000 psi @8gpm pump. here's a suggestion.. http://www.catpumps.com/products.asp?id=341&criteria=1

-use 3/8 hose for your mainline hose, 8 gpm is plenty enough to flush but not so big that you're flooding places out.
-use 3/8 warthog, root ranger and SIZED aqua mole nozzles.

The warthog is easier but the ranger is better for cutting and pulling.


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## noefexus (Jun 9, 2011)

gear junkie said:


> Your pump is only 5.6 gpm at 3500 psi and seriously undersized for your engine but it's not hurting anything. Where did you get the 8.5 gpm?


My mistake, I left off a letter on the model number, it's a General TSF2021. It is 8.5gpm max. But, your suggestion for pumps looks like a good one, but they are pretty expensive


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## SewerRat (Feb 26, 2011)

noefexus said:


> OK, will try that. Should I change to a 1/2" hose?





gear junkie said:


> Your pump is only 5.6 gpm at 3500 psi and seriously undersized for your engine but it's not hurting anything. Where did you get the 8.5 gpm? If you decide to keep the current pump/engine setup I would recommend....





noefexus said:


> My mistake, I left off a letter on the model number, it's a General TSF2021.


OK, I didn't look up the part number, thanks Gear. Anyway, point being that you need to calculate or measure the friction loss in your hose, then order custom drilled nozzles accordingly. If your original specs are correct then the calculation I gave you should get you in the ballpark. If Gear's are right I'm way off in left field. Don't get too trigger happy buying nozzles, get one or two drilled first, try them and if you can't build full psi then try ordering a nozzle or two that are drilled for .25 gpm less at your end of hose pressure. I personally don't think that on or two hundred psi at the nozzle is going to make a huge difference, so I prefer to err on the large side, ensuring that my nozzles are flowing full rated gpm even if the pressure is slightly less than maximum. For example, if your jetter is rated 3600 psi and you are generating 3500 at full rpm with the unloader or bypass screwed all the way in, you can rest assured you are getting the maximum performance possible out of the machine, as nothing is bypassing and you are operated very nearly full psi. If you run too small of nozzles, you can get full psi but unless you do a flow test to make sure you could be bypassing quite a bit of water.

So back to the point, once you figure out what nozzle size works best on your machine, then drop the bigger coin on a Warthog or Root Ranger. And don't hold me liable if my suggestion above isn't quite right, it was calculated very very quickly although I actually think it would come out pretty close.

Regarding hose size, remember that when you go to a larger hose size you overcome much of the friction loss obstacle, but the hose weighs so much more due to the extra water it contains as well as the size of the hose itself, that it's a wash. By my math a 1/2" ID hose contains 77% more water than a 3/8" hose, so you would have to dramatically improve the performance at the end of the hose to overcome the extra drag. At 8 gpm I don't think it would gain, rather it might hurt you, although I've never tried it. Our 8.5 gpm nozzles are used on 3/8" hose and work very well.


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## noefexus (Jun 9, 2011)

SewerRat said:


> If you run too small of nozzles, you can get full psi but unless you do a flow test to make sure you could be bypassing quite a bit of water.


Thanks for the explanation. I notice that a lot of water is going back into the tank from the bypass hose.


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## noefexus (Jun 9, 2011)

I tested my machine today. I cleaned a ram nozzle (all rear pointed jets) and ran it wide open. The gauge read 3,600 psi. So it is running at full pressure...I guess 8gpm at 3,600 just isn't powerful enough...


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## Sewer Saint (May 5, 2012)

I am slightly confused, but that could just be the chemical fumes I had to deal with today talking...

If it is pumping 8 gallons a minute at 3,600 PSI that should be powerful enough for most jobs. My smallest jet is 6.5 gmp, 4,000 psi and I use a 5/8" hose and a 1/3 egg head for most of my small work. I usually run it at 3,500 psi which is usually sufficient.

What are you expecting out of the machine? A jerk rocket like my 18 gmp, 4,000+ psi heavy duty firehose I use one 12" main sewer lines? Have you ever used a hydro-jet before or a ram jet?

I am asking because I have had issues with plumbers just getting into hydro-jetting and having never dealt with such machines or powers were expecting something far different then what they were dealing with.

Rams often do not shoot straight down lines. In 4" lines you will often get lip catches, especially in terracotta and old cast iron lines and you often have to jiggle it a little to get a straight run. The key to the jet is not it's going forward but knowing how to worm your line and the draw back. 2 feet out then 1 foot in as you scrub the line.

So is it an issue of you not knowing what to expect or is it something else?


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## gear junkie (Jun 20, 2008)

noefexus said:


> I tested my machine today. I cleaned a ram nozzle (all rear pointed jets) and ran it wide open. The gauge read 3,600 psi. So it is running at full pressure...I guess 8gpm at 3,600 just isn't powerful enough...


Maybe it's not, you probably need to sell it. OR....buy new nozzles because that's your problem. And make sure they're sized correctly and the size is NOT 8.5 gpm st 3600 psi guarenteed. Or just sell the jetter and buy a 4018 and be done with it.


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## noefexus (Jun 9, 2011)

Sewer Saint said:


> I am slightly confused, but that could just be the chemical fumes I had to deal with today talking...
> 
> If it is pumping 8 gallons a minute at 3,600 PSI that should be powerful enough for most jobs. My smallest jet is 6.5 gmp, 4,000 psi and I use a 5/8" hose and a 1/3 egg head for most of my small work. I usually run it at 3,500 psi which is usually sufficient.
> 
> ...


Yes, I think the jetter does ok. It's my stepdad. I think he's used to larger machines that put out 16-20 GPM, running on a diesel engine, with the larger hydraulic hose reel that assists going forward and has the quick rewind function. He's being a spoiled little brat. Thanks Guys :thumbsup:


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