Running pump question


From actual experience, how long can my 4gpm pump run without triggering the wand before I should be concerned about damage?

I try not to let it go more than a minute but is that realistic?


About 3 minutes without a buffer tank


What about with a buffer tank? Putting a new Udor pump on my engine and want to take good care of it.


About 100 hours if you kept fuel in it. Then you would need to shut down for a few minutes for an oil change




Certain manufacturers have tested bypassing to a buffer tank as small as 3 gallons for 24 hours and water temps never exceeded 110 degrees F.
Without a buffer tank, I wouldn’t go much more than 3 minutes.


I don’t think my pump is set up for buffer recirc.


You probably have one of those built in unloaders?


Yeah, Cat 4gpm/4k.


30 seconds.

3 mins if its cold.


I agree, less than 2 minutes and the head temp will be close to 200 degrees, I tested one on my old CAT pumps with a temp gun. It happens FAST!


It’s too bad the thermal relief valve isn’t more robust, I’d rather it shoot water out the side than have to press the trigger every minute.


Some may disagree with me, but you can just disconnect the looped hose from the intake side and run that hose thru a hole in your trailer onto the ground. Yes, it’ll pump water on the ground while your off the trigger, but is only water and it’s easy! Plug the hole in the intake and your al set. You can let run off the trigger all you like.


I don’t have a looped hose.


Oh, I see. If it was a 66DX or a 6DX It would, sorry for Assuming. I’ve never dealt with the built in unloaders.

Can u get a front shot of the pump, you may be able to add a real unloader to that pump.


Run it the way it is…make some more $ with it and then when it blows up get a gear drive 5.5 @ 2500. It will take a while for that pump to blow up.

I had a cat direct drive I left on for 30 minutes off the trigger on accident. ( I switched to water fed pole) but another machine was running so the engine noise didn’t set off an alarm. The pressure relief valve opened up and let water come out. I was suprised there was no damage. Ran great for another 200 hours before it got retired


Good to know, I made sure it had a Cat from what I heard about quality. Too bad rebuilding it is a PITA.

A 5.5/2500 is definitely in the lineup at some point.


Do you do much flat work? I only ask because today I was cleaning paving bricks and 2500psi with a surface cleaner wasn’t enough.

It didn’t move the heavy mould at all. It came off with the lance and nozzle, but you could leave the surface cleaner over it forever and it was still there.

I switched to my 3500psi machine and it came off with the surface cleaner no problems.

Maybe 3000psi and 5GPM would be better if you plan to do flat work…


I just got started in early September, but I do have some spring flatwork lined up. Too bad I can’t drop my machine down to 3k/5gpm. It’s just an add-on to my main window cleaning business, so who knows where it leads.


I am thinking I must be the luckiest SOB on the planet.

I have a machine that I bought some years ago for $250 from Home Depot - a Dewalt 2.5 GPM that I have never changed the oil, never winterized, let run for 10-15 minutes a time without pulling the trigger, thrown in back of the truck and drove all over Texas for weeks on end with it rolling around and to this day, it still fires up and runs great…

Gotta go buy a lottery ticket real quick.