# Pressure jet question



## Nayman's Drain (Dec 17, 2010)

While I understand cavitation & what causes it, I have never been able to get a satisfactory answer to the opposite.

I own a jetting machine, spec'd at [email protected]
Average use is off either 1/2 or 3/4" fed hose-bib,( average mains pressure between 50 to 75psi) going into a 5/8"-50' hose.

The question is:

Is it possible to overload the jetter on the intake side?
Either with pressure or GPM?

I have been wondering this for over 4 years, and asking, but no-one has ever been able to answer. SO, with the only stupid question being the one that was never asked, I'll take any comers.
Thanks,
Nayman


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## Lifer (Nov 23, 2010)

Cavation would not come into play in this situation because it is more like a pition pump building pressure with pistons and valves not a circumferential style pump/circulator with a diffuser and disk style. So as far as I can tell you are safe with some or a lot of pressure and GPM ....


All of this is pure speculation on my behalf... .02$



Lifer...


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## Magic Touch III (Dec 27, 2010)

*My $.02*

A Pump rated at X GPM is rated so based upon Y RPM... If you increase the the RPM it can increase the GPM (Flow) if enough water is available....and conversly ,if you lower the RPM you will decrease the GPM (Flow)... That said, if your pump is spec'd to pump 6 GPM at 1450 RPM the intake would be 6 GPM ...but, if you were to up the RPM of the pump and an adequate water source is available it would increase the pumps output and in so doing the intake would increase accordingly...It is not possible to overload the intake on the jetter with the PSI seen in the average residental supply line.. Not sure if this makes Cents ha.Tom


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## Magic Touch III (Dec 27, 2010)

*My $.02*

On the other hand, if a pump is rated at 4 GPM at 4K PSI at say 1450 RPM's.. increasing the pumps RPM will also increase PSI higher than the manufacturers specifications for that pump and running the pump with more RPM's would be overloading the pump as far as the manufacturer is concerned..... So its all in the way you look at it...But on the intake side the pump will pump only what is mathematically possible based upon RPM of the pumps shaft. So yes it is possible to overload a pump on the intake side ..Just depends on how you look at it... The intake side wouldnt worry me because that wont break anything its the output side that will be damaged by running the pump hotter than its specs outline...


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## Nayman's Drain (Dec 17, 2010)

OK, same answers I have been getting, but I don't think this has anything to do with math equations.
If I don't run the engine, the water pressure from the bib IS slowed down quite a bit, spraying out of my jet head in a trickle.
I guess what I'm asking is: Can seals in the pump be over pressurized from the intake side.
I am, in essence, trying to determine if the opposite of cavitation is possible.


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## 1703 (Jul 21, 2009)

Nayman's Drain said:


> OK, same answers I have been getting, but I don't think this has anything to do with math equations.
> If I don't run the engine, the water pressure from the bib IS slowed down quite a bit, spraying out of my jet head in a trickle.
> I guess what I'm asking is: Can seals in the pump be over pressurized from the intake side.
> I am, in essence, trying to determine if the opposite of cavitation is possible.


I'm having a hard time understanding what exactly your asking.

You say without the pump running the pressure from the hose bib is slowed down. Do you mean VOLUME instead of PRESSURE?

Are you asking if damage to your pump can occur if the incoming pressure is raised to some particular pressure?


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## Nayman's Drain (Dec 17, 2010)

ok, Cavitation occurs when the supply does not meet the demand of the pump, right?
eventually, it breaks the pump.

What I want to know is:
Can the pump be busted by over-supply of either pressure or GPM?

I'm talking the intake side of the pump, not the output side.

I really don't know how to better ask the question, but in reply to Colgar.............
In essence, yes.


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## 1703 (Jul 21, 2009)

Nayman's Drain said:


> What I want to know is:
> Can the pump be busted by over-supply of either pressure or GPM?
> .


If hooked to domestic pressures than no, I don't see where any damage could be done.

But I'm no pump builder either......


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## Magic Touch III (Dec 27, 2010)

*mo $.02*

Now if the pump is not running it is possible for water to flow through the pump because ie... the plungers are not seated...This flow would be slight and vary based upon your water supply PSI... If you dont want that to happen just shut the intake valve off.. But in any case this overload (If you want to call it that)..will not damage your pump. Might make a mess tho...Tom


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## Nayman's Drain (Dec 17, 2010)

Thanks guys.
NOW I'm starting to get answers I'm looking for.


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