Announcement Announcement Module
Collapse
No announcement yet.
Jetter pressure readings problem Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts

  • Jetter pressure readings problem

    I was playing around with my jetter today checking different configurations etc. Anyway Picture the jetter with a 50 ft 3/8 hose leading to a footswitch then a 2ft jumper to a pressure gauge then hooked to either a 1/4" 200 ft reel or a 3/8 200ft reel. A warthog 3/8 head on either reel. The 1/4" hose reel is giving 3000psi, but the 3/8 reel is showing 2500psi. I would have thought it would have been the other way around. Is the 1/4 reel acting like a funnel to the tip that's why the psi is so much higher? Tomorrow I will be playing with a gauge at each end.
    Seattle Drain Service

  • #2
    Re: Jetter pressure readings problem

    Originally posted by Cuda View Post
    I was playing around with my jetter today checking different configurations etc. Anyway Picture the jetter with a 50 ft 3/8 hose leading to a footswitch then a 2ft jumper to a pressure gauge then hooked to either a 1/4" 200 ft reel or a 3/8 200ft reel. A warthog 3/8 head on either reel. The 1/4" hose reel is giving 3000psi, but the 3/8 reel is showing 2500psi. I would have thought it would have been the other way around. Is the 1/4 reel acting like a funnel to the tip that's why the psi is so much higher? Tomorrow I will be playing with a gauge at each end.
    The larger hose is allowing more water to flow out so the pressure will be less. As the smaller hose is restricting the flow which in turn is going to increase the pressure.
    Ron Hasil Lic #058-160417
    A-Archer Sewer & Plumbing specializing in:
    Tankless Water Heaters | Drain and Sewer Cleaning
    Sump and Ejector Pumps | Backflow RPZ Testing

    Comment


    • #3
      Re: Jetter pressure readings problem

      Cuda, won't the smaller diameter line show a higher pressure at a given pump / engine RPM since less water = less work?

      Comment


      • #4
        Re: Jetter pressure readings problem

        And with the smaller hose no water is coming back into the tank while the footswitch is depressed.
        Seattle Drain Service

        Comment


        • #5
          Re: Jetter pressure readings problem

          I guess I need the gauge at the end to satisfy me, Because I have always just left the warthog on the 3/8 (sometimes I switch it to my 1/2' line to flush) But if I can have a higher psi with the 1/4" and it doesn't bypass back to the tank the warthog will kill roots fast (my thinking).
          Seattle Drain Service

          Comment


          • #6
            Re: Jetter pressure readings problem

            Originally posted by Cuda View Post
            I guess I need the gauge at the end to satisfy me, Because I have always just left the warthog on the 3/8 (sometimes I switch it to my 1/2' line to flush) But if I can have a higher psi with the 1/4" and it doesn't bypass back to the tank the warthog will kill roots fast (my thinking).
            Well high pressure with out the flow it wont kill much at all I would think.
            Ron Hasil Lic #058-160417
            A-Archer Sewer & Plumbing specializing in:
            Tankless Water Heaters | Drain and Sewer Cleaning
            Sump and Ejector Pumps | Backflow RPZ Testing

            Comment


            • #7
              Re: Jetter pressure readings problem

              But if it is not bypassing back to the tank then I should be getting the full flow 10 GPM my machine is rated for.
              Seattle Drain Service

              Comment


              • #8
                Re: Jetter pressure readings problem

                Originally posted by Cuda View Post
                But if it is not bypassing back to the tank then I should be getting the full flow 10 GPM my machine is rated for.
                I guess you have to check the pressure and flow rate at the end of the hose. The unloader will only unload if the PSI gets to high right? but not if the flow is restricted.

                There is something we both are missing in this equation.
                Ron Hasil Lic #058-160417
                A-Archer Sewer & Plumbing specializing in:
                Tankless Water Heaters | Drain and Sewer Cleaning
                Sump and Ejector Pumps | Backflow RPZ Testing

                Comment


                • #9
                  Re: Jetter pressure readings problem

                  Originally posted by SewerRatz View Post
                  I guess you have to check the pressure and flow rate at the end of the hose. The unloader will only unload if the PSI gets to high right? but not if the flow is restricted.

                  There is something we both are missing in this equation.
                  Yea the unloader will open to bypass at what it is set to, in my case at 3000psi at the unloader it opens and bypasses to the tank, so if it is not opening my flow may be deminished a little but the extra 500psi should off set it.
                  Yea I need to finish my testing to see what the psi is at the tip because it should have huge friction loss dropping my psi with the 1/4" and the 3/8 should improve but the psi at the reel is tripping me out lol
                  Last edited by Cuda; 01-09-2010, 11:02 PM.
                  Seattle Drain Service

                  Comment


                  • #10
                    Re: Jetter pressure readings problem

                    need to understand your setup better to answer...

                    was this two separate tests? or one with it all hooked up in series?

                    draw a diagram showing setup, location of gage, and readings. scan it in or snap a pic and post it.
                    Last edited by Ace Sewer; 01-09-2010, 11:55 PM.
                    This is my reminder to myself that no good will ever come from discussing politics or religion with anyone, ever.

                    Comment


                    • #11
                      Re: Jetter pressure readings problem

                      you need to install the tee at the end of the hose right behind the nozzle. then capture the water and measure the volume in 60 seconds.

                      1/4'' x 200' at 10 gpm is not going to happen. not to mention your hose to the foot pedal.

                      takes 27.3 h.p and a #12 nozzle to get the full 10 gpm @3000#. the 1/4'' hose is the deal breaker.

                      rick.
                      phoebe it is

                      Comment


                      • #12
                        Re: Jetter pressure readings problem

                        Originally posted by Ace Sewer View Post
                        need to understand your setup better to answer...

                        was this two separate tests? or one with it all hooked up in series?

                        draw a diagram showing setup, location of gage, and readings. scan it in or snap a pic and post it.
                        Separate tests. Machine-3/8 line-pedal-gauge-reel with 200 ft line-warthog
                        Seattle Drain Service

                        Comment


                        • #13
                          Re: Jetter pressure readings problem

                          Originally posted by PLUMBER RICK View Post
                          you need to install the tee at the end of the hose right behind the nozzle. then capture the water and measure the volume in 60 seconds.

                          1/4'' x 200' at 10 gpm is not going to happen. not to mention your hose to the foot pedal.

                          takes 27.3 h.p and a #12 nozzle to get the full 10 gpm @3000#. the 1/4'' hose is the deal breaker.

                          rick.
                          I would be willing to sacrifice say 2GPM if I can gain 500psi at the tip.
                          If I can alter things with hoses for certain jobs it is a lot cheaper than buying a new pump.
                          All of this is because I have been disapointed with my jetter in 6" and 8" pipe on roots at the top of the pipe. I know and understand on the 8" because I have the warthog 3/8 and am considering the warthog 1/2ws or the double root ranger and switch over to 1/2 hose
                          Last edited by Cuda; 01-10-2010, 12:29 AM.
                          Seattle Drain Service

                          Comment


                          • #14
                            Re: Jetter pressure readings problem

                            ok,

                            now I think I understand...

                            machine, 50' 3/8 hose, footswitch, teed off gage, then

                            test 1: 200' 1/4 inch + warthog, 3000 psi

                            test 2: 200' 3/8 inch + warthog, 2500 psi

                            correct?

                            makes perfect sense.

                            to understand it, LOSE THE IDEA THAT A PUMP MAKES PRESSURE.

                            it doesn't. the pump makes FLOW.

                            the pressure happens as a restiction to the flow the pump is making.

                            unhook everthing from the pump except your gage jumper and run it wide open if you don't believe me; there will be only a few hundred psi.

                            when you put smaller hose downstream of the gage, it is harder to push the flow through it, so the gage will read higher pressure.

                            ---------

                            I think your unloader is bypassing some. is your pump manifold gaged? I think you'll find you are maxed at the manifold and not getting your full gpm to the nozzle with either setup. at 5-6 gpm with ~300' of 1/4" I've got about 2kpsi at the pump manifold just to push it through the hose. pressure ramps up alot as you increase gpm, and I think at 10gpm you will be well over the unloader with the setup(s) you describe, and are not fully using the capabilities of your machine.

                            ----------

                            is this clear to you? can I explain it better? it's a tightrope act to get it all in balance so you can use what you've got to do what you want....

                            you've only got so much psi capacity at the pump before you blow it up or it goes over relief. pump make the flow it makes. trick is to get the flow to the nozzle and make all the pressure there, not in pushing it through the hose and fittings along the way. so you want to keep the flowpath as unrestrcted as possible on the way to the nozzle. but a big diameter hose is a pain to get thru bends, so you have to give up some psi there...

                            take a hard look at your fittings/connections between reels/etc. one too small fitting will cause a huge pressure loss.

                            if that 50' of 3/8 never goes in the line, just gets you to where you are going to work, step it up to 1/2, and keep the connecting fittings huge, and don't use quick connects that shut themselves when not connected; those are huge restrctions, use the ones that are an open shot thru them.
                            This is my reminder to myself that no good will ever come from discussing politics or religion with anyone, ever.

                            Comment


                            • #15
                              Re: Jetter pressure readings problem

                              paul d posted this link a while back


                              http://www.sewerjetgazette.net/press...r-jetter-hose/

                              the table doesnt go anywhere near your gpm, but look at the trend in the smaller hoses when gpm goes up. try to push more gpm through too small a hose and you hit a wall of pressure. you spend all you psi just getting there, and little is left for the nozzle.

                              I see from your tests you're adding 500 psi by going from 200' of 3/8 to 200' of 1/4"

                              looking at that table, and knowing that the psi's in it are a little high compared to my experience, I think you're only getting 5-6 gpm to your nozzle. the rest is going over your unloader.

                              gage your pump manifold if it isnt. there is usually an extra port on it. the run it wide open with just the 50' 3/8 and footswitch and see how much psi you've got at the manifold just to push it through that. compare that to the max psi of your pump. try it again w/o the footswitch. For some reason, I've got a suspicion that footswitch is hurting you. what size is it's valve? is it full flow when open? it should be at least a full open 3/8" hole, probably 1/2".

                              or just try taking the footswitch out and running your same test again; if you pressures go up much w/o the footswitch, it was hurting you.

                              once you figure out how much you are losing on that end and open it up as much as you can, it'll get confusing again when you add hose downstream as you'll be pushing more flow, so it'll all change again.

                              also, what size is your jumper for the gage? doesn't matter about the leg that goes to the gage, that can be tiny, but if the legs the flow goes through to get to the nozzle are small compared to everything else, you'll throw off your data because you've added a restriction there.
                              Last edited by Ace Sewer; 01-10-2010, 01:32 AM.
                              This is my reminder to myself that no good will ever come from discussing politics or religion with anyone, ever.

                              Comment

                              Working...
                              X