General Pump TX1510A - Questions

"Red"

"Red"

Graphic Designer
I bought this PW used. The seller claimed 4000psi / 4GPM and I though nice entry level machine and off I went.

Once I got 'er home, I looked up the model number on the pump and the best I could figure out is it's 3000psi / 4GPM. General Pump doesn't even list this specific model on their website. The 63 series is as close as it gets.

My questions are (please refer to the graphic)

  • If the regulator won't turn, is that a bad thing? I'm a good size fella and none to weak, but this thing won't budge.
    (I don't even feel any movement when pressing down)
  • Is the Regulator also an unloader?
  • Is the chemical port good for down streaming or would an adjustable inline be better?
  • Can a pressure gauge be mounted in the "Blocked Port"?
  • Any idea what this "Thingy" is?

General-Pump-TX1510A.jpg
 
Here's the breakdown of your pump. It is rated at 3,000 psi.
http://www.generalpump.com/pdfs/TX1508G8UI-pump.pdf

If the regulator won't turn, is that a bad thing? The knob turns a brass nut under it. Slide the knob off and put a wrench on it.

Is the Regulator also an unloader? The terms can be interchanged.

Is the chemical port good for down streaming or would an adjustable inline be better? You'd have to order parts to put the chem injector on it, otherwise an add on injector will work fine.

Can a pressure gauge be mounted in the "Blocked Port"? Yes

Any idea what this "Thingy" is? The thingy is a thermal relief valve. If you leave the gun shut off for too long, and the pump tries to overheat, the valve lets hot water out of the head so cool water can get in to save the pump from burning up.
 
Thanks Russ for the fast reply and great information.

I've got a couple more questions.

Can you recommend a good injector?

Can the 'thermal relief valve' be routed back into the tank or does it just splash everywhere?
(I don't intend on letting the machine idle that long, but stuff happens)
 
I bought a used DeWalt DP3750, which is a GX390 direct drive running a TX1510A pump. It's rated at 4.0 gpm, 3750 psi. At first I thought the pump was swapped out, but I have found references to it in service parts lists for the DP3750.

Also, the newer DeWalt DXPW4240, also a GX390 direct drive running a TX1510A pump is rated at 4.0 gpm, 4200 psi.

I called Simpson, as they make these units, but they referred me to a service center phone number which didn't work... I ordered a pressure gauge so I could measure mine and see what it's actually putting out.

Is it possible that Simpson/DeWalt is modifying the TX1510 pumps to run at a higher pressure? Or just running the engines at a higher RPM? I can't imagine that they'd fudge the numbers, 3000 psi vs 4200 psi is way too big of a difference for that to fly...

Rob
 
I'd say they're just praying they'll hold together until the warranty expires.

Simpson was once a high end manufacturer, and you didn't buy them at the big box, only through distributors. They really paid attention to quality.

Now everyone is chasing the dollar. I don't know if you're old enough to remember, but Troy Bilt was a high end rear tine tiller. That's all they did, and they did it quite well.

Husqvarna, the same way. Top notch chainsaws, and kick ass dirt bikes.

Now, you can go to big box and find these names on the cheapest pressure washers made.

Excell was a top name pressure washer manufacturer in the '70s. They started building small machines for Sam's Club, but they were good quality. DeVilbiss saw the potential, bought Excell and the name, and tagged many less than desirable cheap machines with the moniker.
 
Well, I hope it does hold up... I got the pressure gauge today and checked it out, my DP3750 was hovering around 3750 psi +/- 50 at the pump, 3200 with the trigger depressed. I measured it on the other side of a 50' 3/8" hose and was surprised to see the exact same measurements. Theoretical loss should be approx 50 psi I think?

I'm going to get a jetter setup, so when sizing the nozzles for that, do I need to factor in the hose pressure loss and calculate with the pressure at the end of the jetter hose run? I'm probably looking at 50' of 1/4", according to the charts that should put me around 3500 psi at the end of the hose.

Rob
 
I spoke to a tech at General Pump today, he said the TX1510A is a modified version of the TX1510G8UIA. The most notable difference is that there is an upgraded set of bearings installed in order to work at the higher pressures. He was surprised to hear that DeWalt was selling the same pump rated at 4200 psi, but said that General has not heard of any issues with these pumps.

He said, with the trigger depressed, I should only see about a 100-150 psi drop in pressure if I have the right sized nozzle (at a 550 psi drop, my nozzle is probably too big - either worn out or the wrong size).

So I'm piecing together how this system works, and as far as I can figure, the nozzle size dictates the pressure drop, and therefore the pressure in the hose. If the nozzle is too large, the pressure in the hose drops, as is the case with mine. If the nozzle is too small, then the unloader valve will bleed off any excess pressure right back into the pump intake, which means a reduction in volume. Is that about right?

So when people say you are harming a pump by running too small of a nozzle, really what you would be doing is running with the unloader valve partially open the whole time.

I'm new to this, please correct me if I'm wrong. I thought the TX1510A info would be good to have in this thread, since it's the first return on Google.

regards

Rob
 
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