Issue pressure washing from a 55 Gal. drum

Looking for some input on my setup, I am trying to powerwarsh  a building with no water source nearby. The plan was to use a 55 Gallon  drum as a water supply, no go.

The drum (filled to the top access hole) has been set up with a 3/4 inch valve and the top cap has been removed  to prevent  cavitation, known good hose, and the pressure washer was tested  before hand.

When the machine  is running  there is zero water coming from the wand, disconnected the supply hose from the machine and water comes out???

Take the machine  back to the house hook it up the house and good pressure? Back to the building and no pressure,  swapped supply hoses,  no change?

The only thing I can think of is the cheap (soft) garden hose is collapsing  due to the suction of the machine. If this is the case I will try to find a more ridged  hose tomorrow. 

If you see anything wrong with my setup please say something,  first time trying something like this. 

Thanks, Paul

Some of those machines have a backflow preventer built into the inlet of the machine. Maybe you don't have enough inlet pressure to unseat the backflow valve.

See if there is a little widget in the water inlet that might be easily removed.

The washer is expecting to see typical water pressure from a faucet, but all you have is the minimal amount of pressure as a result of the height of the barrel in the back of your truck.  I think you need to figure out a safe way to pressurize the water in the barrel (or put it on top of a 50 foot tower.)

In reply to stuart in mn :

Pressure washers will suck from a bucket. They're a positive displacement pump with poppet valves. They don't need any inlet pressure to function.

I used to repair them in a previous life. To be perfectly honest, the unit you have there is pretty much considered "disposable". The pump may be pretty worn out at this point.

I believe the unit put together ar NHIS back in the 90s to clean up synthetic oil from crashed bikes has a little 12 volt water pump between the barrels and the pressure washer.  

The barrels were on a trailer, I then the pw was mounted to it also, so ther le was less head than your setup.  

Your inlet hose is too long. Shorten up the hose and prime the pump by loosening the inlet fitting while the pump is running with the trigger open

Mr. Peabody,  you are correct! I shortened the hose to 12 feet  and off we go, without any issue. 

Thank you, Paul  B

Peabody said:

Your inlet hose is too long. Shorten up the hose and prime the pump by loosening the inlet fitting while the pump is running with the trigger open

This is interesting. Can you explain why the longer hose wouldn't work?

Friction.

Pressure loss is caused by friction when forcing something through a hose, and the longer the hose, the greater the stack up of friction and pressure loss.

Yup.  Ever try to fill a tire with a really long air hose?  Static pressure will eventually balance out.  With the air flowing, pressure at the end of the hose is lower than at the tank.  If you fill a tire to 100psi with a 10' hose, then try to do the same thing with a 100' hose, it will take much longer.

ShawnG said:

In reply to stuart in mn :

Pressure washers will suck from a bucket. They're a positive displacement pump with poppet valves. They don't need any inlet pressure to function.

I used to repair them in a previous life. To be perfectly honest, the unit you have there is pretty much considered "disposable". The pump may be pretty worn out at this point.

I think this is highly dependent on the pump style.  Wobble pumps would probably do better than axial or triplex.

And sometimes the hose is just too long

Peabody said:

And sometimes the hose is just too long

Nope not touching that!!!   

Curtis73 (Forum Supporter) said:

If you fill a tire to 100psi with a 10' hose, then try to do the same thing with a 100' hose, it will take much longer.

Your statement is only true if the ID of the hose stays constant 

Slippery (Forum Supporter) said:

Curtis73 (Forum Supporter) said:

If you fill a tire to 100psi with a 10' hose, then try to do the same thing with a 100' hose, it will take much longer.

Your statement is only true if the ID of the hose stays constant 

 

Well, my hose looks like this.  Does that count? :)

Jahnoe Canoe

stuart in mn said:

The washer is expecting to see typical water pressure from a faucet, but all you have is the minimal amount of pressure as a result of the height of the barrel in the back of your truck.  I think you need to figure out a safe way to pressurize the water in the barrel (or put it on top of a 50 foot tower.)

You can't put more than about 6psi into a barrel before it turns into a dumpling.  Water systems usually have much more than that.

Used to pressurize barrels to get oil out of them and up into a storage container 10 feet off the ground.

6psi should be enough to provide positive feed, at least.