I had got this hot water machine without any tags on it, and the pump is unknown Chinese origin, no tag on it either. No nozzles were included either.
Right now I am using 4.0 orifice nozzles on my machine, and it’s only running at 2000psi with 40 deg tip. I have a 3.0 orifice white nozzle from another smaller machine, and with that nozzle on this machine it will run around 2800 psi, which is fine for me.
My questions:
How are we suppose to size the nozzles properly for the machine without knowing the specs of the pump? I have done a water test just with my regular hose and I have 6-7 GPM of water flow, so way more than enough for this pump. Are we suppose to run the machine with no nozzle on the gun, and put that into a bucket and see how much it pumps in a minute?
Does going from a 4.0 to 3.0 orifice nozzle also lower the GPM that the machine will put out? Or is that a constant value, and only the pressure changes?
Pump is attached to a 13 horse Honda, pump pistons are 15mm dia.
The short answer is that your pump, operating at the correct rpms, will always put out the same gpm up until your nozzle hits the pressure for which the pump is rated. The nozzle changes pressure, not gpm. If the nozzle is too small, your correctly calibrated unloader will send the excess water to your bypass tank.
At the perfect rpm and nozzle size, you’ll get pretty close to your pump’s gpm rating and be a little low on the psi depending on the length of your hose.
We change our pressure all the time by changing out our nozzles, but the gpm stays the same.
So what is the proper procedure for determining the correct nozzle size without knowing anything about the pump? Just judging by it’s size and engine requirement I’m going to choose to run it at 3000 psi max to be safe.
Run the pump with no nozzle and see how much GPM it puts out?
Thanks. I will do that. Won’t letting off the trigger just trip the unloader? I have it set right now to around 3500psi. No idea what the factory setting was. The unloader spring was broken when I got the machine, so I had to repair it with another spring. I set it to 3500 just to be on the safe side as I don’t know the exact specs of the pump.
When I first started using the machine, it would spike the gauge to over 5000psi before tripping the unloader (it was stuck)…but no way this pump is rated to do 5000psi.
I do, but have been through this before posting it in other threads when I was trying to find a replacement piston for the pump. No one was able to identify the pump. It is made by a Chinese company that is long gone now. I just wanted to know the procedure for finding the proper nozzles.
Here’s the thread if you’re interested.
It was said that it resembles a Comet ZWD-K body, but has regular ceramic coated pistons instead of the pistons they have now. It is not a Comet. There is a name in the casting inside the pump that says “Whale”.
Yes, that would be best for you. Find out your gpms that way, then buy nozzles for what you want. Find a nozzle that will get you close to the highest PSI you plan on ever using, and then set your unloader with that nozzle.
Sounds like it might be a good idea to go ahead and set some $$ aside for a new pump so you don’t get stranded
Yup that’s them. I would like to switch to another pump but the problem is that 1) the pump has a twin shaft with a pulley on the other end to drive accessories. Replacement name brand for these are very pricey, more than the machine is worth. 2) the rest of the unit is built around that pump, with an actual belt driven alternator, and belt driven fan and burner pump.
Ideally I’m keeping an eye out for another good machine I can rebuild, and sell this one.
Side note, I have actually found the specs of the pump thanks to their site!
Apparently the pump I have is 4.0 GPM and 3000 psi. Going from the table, it says I should be using 4.5 nozzles? I have some that I bought (guessing they’re around 4.0), and using the white tip (40 deg) with these only produced around 2000 psi at the pump body, Is that normal?
You need to set the unloader properly with the correct nozzle size. Buy a nozzle that says 4.5 on the orfice you can’t guess that it’s probably a 4 because if your wrong you may set the unloader to high and hurt the machine. Did you get 4gpm on the bucket test? Also, make sure you have a new, quality gauge. Those things don’t last very long and easy to get messed up to read very far off what it actually is.
Haven’t been able to do the bucket test yet as the machine is in winter storage. I don’t use it often. Unfortunately the nozzles I had got were from Amazon, apparently 4.0 orifice, but there is no writing on them, and they are made pretty crappy, so I don’t know what they are exactly. I want to buy better quality ones but was unsure of the orifice size to get.
I have the unloader set for 3500psi. With pump operating pressure of 3000 psi, that should be good, right?
But still to answer my question, if I have let’s say 4.5 orifice size nozzles, pump is rated for 3000 psi, and I’m using the white tip (40 deg), is it normal that the pressure is lower than rated (ex. 2000 psi)? Or is it suppose to actually be 3000 psi on all nozzles?
That’s what I’m saying is you need to start from the beginning. It could be less than what the manufacturer claims they usually try to up the specs of what’s theoretically possible to make the machines look better. I.E they claim 4/4000 but no machine really ever hits that, it’s usually 3-3500.
So if let’s say I’m using the correct orifice size nozzles, pump is rated for 3000 psi, and I’m using the white tip (40 deg), is it normal that the pressure is lower than rated (ex. 2000 psi)? Or is it suppose to actually be 3000 psi on all nozzles?
@Sugarkryptonite, I’m gonna try to help clear things up, but if I get anything wrong then I hope it gets corrected by someone with more experience.
If you’re using the correct tip, then it is not normal to get 2000psi when your pump is rated for 3000psi. That is a big difference.
It is not supposed to be 3000psi on all nozzles, only with the 4.5 tip after you’ve properly set your unloader. Until you have the 4.5 you can’t properly set the unloader.
Right now your unloader is set using the wrong tip, so the 2000psi reading would likely be caused by that. Using a 4.0 instead of a 4.5 should make your pressure go up above 3000psi, not down to 2000psi. Just like going from 4.0 to 3.5 made your PSI go from 2000psi to 2800psi.
You really need to buy a 4.5 tip and set your unloader so that you are getting the 3000psi that your pump is rated for when using that tip. You say you set your unloader to 3500psi, but if you were using the wrong tip then it isn’t actually set for that. It needs to be set for 3000psi when using a 4.5 tip.
Once it is properly set you can change your PSI by changing your tips.
4.5 tip = 3000psi
5.0 tip = 2500psi
5.5 tip = 2000psi
6.0 tip = 1750psi
6.5 tip = 1500psi
7.0 tip = 1250psi
7.5 tip = 1100psi
8.0 tip = 1000psi
8.5 tip = you’re drawing soap
I hope this clears things up for you and that I got all my information correct!
Why do you want so much psi on all those nozzles? Soaping and rinsing should only be about 100-150 psi. Its rare that I use a pressure nozzle on anything besides driveway edges and brick here and there, and then it’s almost always the same tip, in 25 degrees.
You’re not planning on hitting the sides of houses with anything above 150psi, are you?
Just do what we said. Do a gpm test. Buy a 4.5 nozzle, a new pressure gauge and set your unloader to the correct psi and be done with it. Your unloader is off and your tip may be wrong. If you do the things that we said to do and you’re still getting weird numbers then respond again with the results. I’m sure we be happy to help from there but at this point we’re starting to go in circles. Oh god I’m starting to sound like @Innocentbystander lol
