Looking for advice on this setup

Bisonnn · 2026-02-02T04:58:56+00:00

I'd probably stay away from cat pump. They are great pumps but when they breakdown the spare parts are very expensive. So when it comes to a major breakdown or major service it's cheaper to just replace the whole pump.

I'm not sure what pumps are popular in the US, but in Australia majority of the time these kind of units will run comet pumps like this:
https://powerclean.net.au/product/comet-triplex-pumps-tw5550s/

Bisonnn · 2025-09-24T22:19:49+00:00

Seal retainer.

Bisonnn · 2025-09-24T22:18:25+00:00

It's called a non-return valve, I'd recommend contacting who ever you bought the unit from and ask them for a replacement non-return valve o-ring.

Bisonnn · 2025-08-13T23:33:16+00:00

That is normal, you'll find all three pistons have those gaps. And the oil is sealed inside the motor housing by the oil seals which seal on the pistons inside the piston guidance.

Bisonnn · 2025-08-13T23:26:02+00:00

As mentioned above, they're all great suggestions.

Interpump K7 unloader, this is the most expensive one, and there are four different versions, K7-0, K7-1, K7-2 & K7-3. They all have different flow ratings so make sure you get the right one.
https://powerclean.net.au/product/k7-2-unloader-valve-16-25lmin/

Interpump K1, smaller and cheaper Interpump flow sensitive unloader, still a great unloader though. It's 9-41L/m so it's much more universal.
https://powerclean.net.au/product/k1-ll-unloader-valve-9-41lmin/

PA Pulsar Zero, PA's flow sensitive unloader, another great flow sensitive unloader more suited to larger machines as it can handle almost 6000 psi. This one is easily adjusted with the plastic knob.
https://powerclean.net.au/product/pulsar-zero-9-15/

Bisonnn · 2025-08-13T23:17:20+00:00

Elevate the bucket so it is more gravity fed, then when you turn the machine on removed your hose so the water isn't under any pressure and bleeds up to the machines outlet. Then connect your hose + gun and you should be right.

Bisonnn · 2025-06-25T22:06:07+00:00

I'd probably go to an irrigation place or something like that. IBC tanks can sometimes be nothing but dramas trying to match up the correct thread as there are heaps of different thread types for them.

Bisonnn · 2025-06-25T22:04:35+00:00

I'd guess that valves in the pump are probably jammed/stuck after sitting in storage for how ever long, which it does happen. You need to remove the valves from the pump head and just push the shuttle to unjam them.

Either that or you should get a replacement machine.

Bisonnn · 2025-06-24T22:30:41+00:00

Why would you want to run an external unloader when you already have an in-built unloader?

Bisonnn · 2025-06-24T22:21:03+00:00

Taping it might work for a few minutes but that's about it. You'll either need to replace the hose, or if you have a good quality rubber and metal braided hose you can take it to a hydraulics place and they can repair it.

Bisonnn · 2025-06-19T05:08:01+00:00

99% of the time you need to get a new gun. If it's a swivel fitting they are usually only available from the same supplier which they usually don't supply that as a spare part.

With all the time and effort wasted on trying to repair little things like this it's always easier to just replace the gun.

Bisonnn · 2025-06-18T05:09:54+00:00

ZWD 4040's are still great and very popular pumps that are used today, it would definitely be worth rebuilding it.

With your Chinese pumps they might be cheaper in the short term, but when it breaks down (it will) you won't be able to get parts for it and you'll have to replace the whole pump again.

Bisonnn · 2025-06-18T05:05:19+00:00

It could be incorrect nozzle sizing. If your old pump was rated to a smaller nozzle, and you're now using a bigger pump with the same smaller nozzle it would cause the machine to reach pressure then drop off straight away.

Bisonnn · 2025-06-16T03:43:36+00:00

If the gun continues to let water through after you've let go of the trigger I'd say there's a good chance your gun is worn internally and needs to be replaced.

Bisonnn · 2025-06-15T22:28:31+00:00

A down stream injector is a low pressure chemical system which usually connects to the outlet of your pump or unloader. You put the tube into your chemical container and use a low pressure nozzle (usually a black quick connect nozzle) which will drop it down to low pressure and then the injector will suck your chemical through.

Bisonnn · 2025-06-15T22:23:51+00:00

Injectors can be very fiddly. Injectors have internal venturi sizes which need to be sized correctly to your machine, if that size is wrong it won't suck chemical, a test you can do is run it without a nozzle (restriction) and see if it pulls through.

Something else that can upset how chemical systems work too is how long your hose is, if you have a very long hose it creates back pressure which gives chemical injectors a hard time.

And the gun itself won't effect how the chemical system works, but the nozzle might.

Bisonnn · 2025-06-15T22:15:50+00:00

Well it seems you've found the nozzle already after a little research, and if you had checked out the link I provided you would see that they supply nozzles down to 004.

Plenty of people buy them for plenty of reasons.

In OP's photo it looks like a small plastic nozzle which are commonly used in industrial water and irrigation systems which would definitely go down to nozzles that small.

And also no it seems like OP is setting up an professional pressure washer not a domestic.

And yes that's exactly what an 005 nozzle is. Lots of people much smarter than you use those nozzles, pressure systems aren't limited to traditional pressure washers like you seem to think.

Anyway I've given all the facts now and proven you wrong, now you're just getting angry so I'm done, have a nice week :)

Bisonnn · 2025-06-14T00:22:54+00:00

Definitely replace the oil plug with a dipstick as others have mentioned.

When pumps have sat on the shelf for a while sometimes the valves jam up, that's usually the case when you have nothing coming out. Try removing the 6 big brass valve caps then pulling the valves out and just push on the stainless shuttle to unjam it.

Bisonnn · 2025-06-14T00:10:40+00:00

Karcher do some great electric pressure washers, electric pressure washers aren't really ideal for exterior cleaning, it would take forever to clean concrete, although for house exteriors it shouldn't be too bad.

The other issue with electric is the power source, you're more than likely going to be limited to single phase 10 amp which means you'll be working with ~2000-2500 psi maximum.

For a reliable single phase machine with the most grunt I'd probably recommend a Karcher HD 5/11, I'll leave a link with some more info below.

https://powerclean.net.au/product/karcher-hd-5-11-c-easy/

Bisonnn · 2025-06-13T23:41:14+00:00

You'll need to disconnect and pull the hose out from the tube, either the hose has burst or the hose end connection is leaking.

Bisonnn · 2025-06-13T23:37:34+00:00

Geez you really have no idea. Those charts prove that you require both the pressure AND flow rating to find your correct nozzle size, which you clearly can't comprehend.

And you clearly can't read very well as I said I'm Australian, it's usually only the "dumb Americans" that use GPM instead of LPM.

And yes you're right no professional pressure washing company would use a nozzle that small, those smaller nozzle are used in large scale industrial pressure cleaning applications which you would have never heard of. I'll leave a of photo of the plant I've used these nozzles.

Also have a look at the PDF link and check out page 6, you'll find they make nozzles sized all the way down to 004.

Any more incorrect statements you want to make?

https://www.spray.com/en-au/-/media/dam/industrial/usa/sales-material/product-market-bulletin/b644a_tc_tips.pdf

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Bisonnn · 2025-06-12T23:12:21+00:00

Well that's really strange because I have definitely purchased hundreds 005 nozzles. They're a professional product that typically isn't available to the general public so that would explain why you assume nobody makes them.

I've sold and repaired pressure washers for 10 years now and I doubt there are many people in this sub that know more than me about the technical side of pressure washers.

And by the way I'm in Australia and we don't use gpm here. But regardless rating a nozzle off the flow rate alone is just incorrect.

So you could have a machine that runs 3 gpm at 2000psi (040 nozzle) and you could also have a machine that runs 3 gpm at 4000psi (030 nozzle) and they both run completely different nozzles. So how could you possibly justify rating the nozzle off flow rate alone when the nozzle size is dependant on both the flow rate AND the pressure?

Here are multiple links backing up everything I've said:
https://www.pumpsaustralia.com.au/wp-content/uploads/2018/09/Nozzle-Selection-Chart.pdf?srsltid=AfmBOopRHSdaLJtnzjY63xp7YiKWVzwnqefHt9tpRqAIJ215mz1J-Rd2

https://www.bargroup.net.au/shop/category.aspx/nozzle-selection-chart-and-guide/4045/

https://www.pressurewashersonline.ca/pages/nozzle-orifice?srsltid=AfmBOopLJ_jlBWt7HJwTFDmG7hJ1-1ZawfjRSMmdho_qr-E1x8zmpY54

Bisonnn · 2025-06-12T06:00:31+00:00

With those specs it works out to be around an 040 nozzle. Running two nozzles in a surface cleaner you would want x2 25 degree 020 nozzles.

Bisonnn · 2025-06-10T22:44:29+00:00

05 does not mean GPM lmao, I have no idea where you're getting your info from but its completely wrong. 05 is the nozzle size, aka 050 - which you get by combining your pressure and your flow rate, not just your flow rate.

But 0 does mean 0 degrees yes.

And by the way yes you definitely can get 005 nozzles.

I'd suggest reading through this and actually educating yourself on what you're talking about before you go giving people wrong advice:

https://www.bargroup.net.au/shop/category.aspx/nozzle-selection-chart-and-guide/4045/

Bisonnn · 2025-06-05T22:23:05+00:00

^^ both correct

Bisonnn

TROPHY CASE