answer to gravity fed pressure washers

detailpowerwash

detailpowerwash

New member
I was once the guy lookin for the answer to the reason why my pressure washer just wasn't getting enough water feed from the tank....the simplest answer is increase your hose from the tank to the pressure washer to atleast a 1" i.o and connect it directly. I went thru a lot of trouble to figure this out and now that I know I hope this helps anyone wondering the same thing...some helpful tips include making sure your tank is above your pump and clearly have enough water to help gravity feed it down.
 
You're welcome chad! And I filled out my signature not sure why its not showing up...maybe because I'm mobile :/
 
Had same problem. Suction from pump seemed to collapse hose. Was suggest by co-worker to use flexible pvc spa tubing (home depot has it) to make a connecting hose. worked very well.
 
Spend some time searching the forums, all this has been discussed many, many times over the years and will help you save a lot of time and aggravation and possibly help save the packings in your pumps.

For the suction hose, don't use the clear poly hose, it will collapse, especially when it is hot outside. Use the thick walled utility hose (air water gas hose) or the wire spiral hose so it will not collapse.

On the pumps larger than 5gpm, it is recommended to use a 1" supply line from the tank, if you have multiple machines, have multiple bulkhead fittings on the tank so the pumps are not fighting for the flow.
 
If I use PVC pipe 1" from my 400 Gallon tank staged at least 6" above my pressure washer to my Direct Drive 4000 PSI, 4 GPM will I have the gravity pressure to work? Or must I go with a belt drive or gear box pump? I'm really hopping the first will work as I have 4 direct Drive pumps.
 
First before you do anything, get the info off the pumps and call Russ Johnson to see if they can be tank fed, most cannot and some can pull from a tank.

If your pumps can pull from a tank then just put the bulkhead fitting at the bottom, the pumps that can pull from a tank will pull from the bottom no problem. A separate bulkhead fitting for each pump so they are not fighting each other for water when running.

If your pumps will not pull from a tank then you will have to just keep running them with garden hoses with good flow.

I would not try to pressure a tank as that can slow down the water flow into the tank and too much pressure can rupture a tank, most water tanks are not designed for pressure, just for holding water.

Installing bulkhead fittings 6" above the pump will not only reduce the available water supply in the tank but is not needed if your pumps will pull from a tank, this is not known until you call Russ with the pump numbers to see for sure but 6" above the pump will not give you the pressure you need, most water supply is from 30 to 80psi, the tank will not do this.

Call Russ and find out first.
 
Smith & Sons said:
If I use PVC pipe 1" from my 400 Gallon tank staged at least 6" above my pressure washer to my Direct Drive 4000 PSI, 4 GPM will I have the gravity pressure to work? Or must I go with a belt drive or gear box pump? I'm really hopping the first will work as I have 4 direct Drive pumps.
Click to expand...

The size of the tank has no bearing on this equation. The height of the water determines the pressure. You could have a five gallon bucket set up on a step ladder and every foot in pipe height would add about 1 psi. 1" or larger free flowing pipe from tank to inlet with minimal elbows would allow you to test to see if any of your machines will gravity draw.

I have heard that the direct drive spin too fast to draw. What if you you started it at a slower speed to prime it?

Understand that these are simply exercises in "what if" and are not meant to be any kind of permanent solution.
 
I have a 5.5 GPM pump that is driven through a gear box and it's fed from a 275 gal. tank using 3/4 inch pvc. If you'll use pvc you won't have to worry about collapsed lines. My pump sets about 6 inches higher than the bottom of the tank and it will suck my tank dry. I know this because it happened once (Cavitation is not good for the pump). Chris is right, call Russ Johnson at Southside Equipment. He can help.
 
A direct drive pump will turn the same rpm's as your engine (Honda GX390- example 3,600 rpm). We have some belt drive pumps that turn 1450 some that are 1750. That is a big difference.The piston's on a belt drive pump are also much larger. As I stated earlier I learned the hard way. A direct drive unit will run from a tank but you will be running the pump dry until it is primed. This will damage the packings and you will be spending money more often than you should. You will also find you will not be getting the full pressure from the pump. I ran a Surflo pump between the tank and pressure washer for a while with a check valve between and it worked for a while but still had wear problems with the pump. I understand you are trying to work with what you have, I was there myself many years ago. That is one of the reasons I try to help folks. This is why I always ask questions about how someone is going to use the pressure washer when they come in our shop.
 
Rance said:
I have a 5.5 GPM pump that is driven through a gear box and it's fed from a 275 gal. tank using 3/4 inch pvc. If you'll use pvc you won't have to worry about collapsed lines. My pump sets about 6 inches higher than the bottom of the tank and it will suck my tank dry. I know this because it happened once (Cavitation is not good for the pump). Chris is right, call Russ Johnson at Southside Equipment. He can help.
Click to expand...

I have had the same experience with PVC running a 5.5 GPM direct drive.

Sent from my DROID RAZR HD using Tapatalk 2
 
Nibbsy in Australia has a bilge pump to feed pumps above tank, not sure if this would help for a direct drive.
 
Another vote for PVC. And just and FYI, if pump damage occurs from a gravity feed setup, it will be tough getting it covered under a warranty claim.
 
I'll be changing over the plumbing to PVC when my new unit gets here in about 3 weeks. I'll dual feed it with either 1" or 1 1/2". I have a 8 GPM 3500 PSI unit on order now from Silver Eagle.
 
You must log in or register to reply here.
Back
Top