Nozzle orifice size for roof pump?

I have a 7gpm pump and have tried to use it for washing roofs many times. It barely works at all, is it maybe that I’m using an incorrect tip? I’m just using the one that came with the pressure washer.

What color/size is it?

What size hose, what size nozzle, and what gun are you using? You can probably get a quicker answer if you show a picture of the set up, I’m sure it’s a easy fix.

With what pressure washer?

Ahh I thought he meant 12v

I think he is trying to use the tips that came with his p washer to 12v. And I’m pretty sure he doesn’t have a 7gpm unit but I’m guessing. We are about to find out or he just realized that he has a 4gpm unit and is trying to use them with a 7gpm pump

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Its a 12v 7gpm diaphram pump

yes it is

So the pump you bought came with tips. You are going to have to post pictures if you want help

Its half inch hose, the tip says 40040, its white. I tried it with a 0 tip as well and it was just weak.
here is a video:

You’re using high pressure nozzles that’s your problem. You need to use a soap nozzle that had a wide orifice. Try it with your black tip. Then order something like a 2540 and a 0040. You’re currently trying it on a 4004 and 0004.

Just buy a $2 Gilmore gun and be done with it.


yeah i thought that might be it. I ordered some 40 tips, thanks for the reply

Gilmore gun would work for sure. A lot of guys use those. Another problem is you’re using a PW gun. Use a pvc ball valve with like a 12in 1/2in lance and a quick connect on the end or use a Gilmore gun/garden hose gun

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It’s your gun stop using that build a ball valve gun you will be way happier

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This is what I use, thanks to @Racer.
1/2in Barb to thread
1/2 threaded pvc ball valve
18in 1/2in threaded pvc pipe
1/2in pvc female to female
1/2in male to 1/4in female brass reducer
1/4in quick connect for your nozzle

It can all be found at home Depot. The nozzles I use are 2540 and 0040. I have a 5.5gpm with 200ft hose. The more hose you use the less GPM you get but I wouldn’t roll with less than 200ft


Very helpful, thank you, I was also wondering, I have my hose connected to a regular pressure washing hose reel, and i notice its rusting and turns the liquid red, should I be using a different type of hose reel?

If your running high concentration of sh you need to convert the guts to stainless. Also flush the pump reel and hose for at least 5 minutes after you are done. Never let sh sit in the line

ok thanks, On the website where im looking at nozzles they have #02.0 all the way up to #60.0, for roof washing I guess I should get a #40.0? and for downsteaming which should I get?

Well that all depends on your machine and what you are trying to clean. What gpm is you pressure washer? What kinda pressure washing do you do.? What chemicals do you use? What ratio is your ds?

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