Power Washer

[Bill from Scotland]

I have a Karcher power washer which is under performing - low pressure. I suspect the low pressure is due to low feed pressure, feed comes from a 1/2 inch pipe gravity fed from the loft of my two storey home. Tried running the tap to fill a bucket then allowing the washer to suck water directly from this (acted as a reseviour) but it didnt help much. Does the feed have to be at a good pressure? Has anybody any ideas on how to improve the washer performance.Took ages today to wash mud off my Ford.
Thanks
Bill

Thanks
Bill
 

[MSM]

It needs more inlet pressure than the gravity fed system. I would suggest a small gas powered pump if you aren't near a power source.I use a small 2 stroke Tanaka pump feeding the washer when I wash out radiators out in the field drawing out of a 600 gallon tank. You probably needs 20 psi minimum for the washer to perform properly.
 

[David G]

The manual should state what the minimum inlet pressure required is. I forgot that you guys over the pond all have gravity feed systems.

A centrifugal pump should work to stuff the pressure washer. You never stuff a PD pump with a PD pump, something will blow.
 

[JDseller]

Most of the modern piston pumps have to have a minimum of 10-15 PSI on the inlet to pump correctly. The old HY PRO piston pumps would actually suck water in. They where labeled for gravity usage.

Also I have found that Karcher consumer grade pressure washers are not very good to start with.
 

[dave2]

I've got 2 karchers... a cheaper (2500?) model and the bigger (5.6?)...
The smaller one works fine on gravity feed the bigger I haven't tried but works good with a looooong feed hose (= lower pressure)....
You can download free .pdf manuals from the karcher site....
 

[paul]

I've got an older, but not heavily used, K machine, 2400psi, 5hp engine.

It can be the lack of input pressure/volume, I donno, as you mention?

They also develop a problem where the valve sticks.

I found simple directions on the net on how to solve that - take off the silver cap, take a tiny screw or 3 out, run it so the valve pops out (as they say, the toughest part of the whole process is finding the valve again when it flies away...) putting some grease on it, and re-assembling.

Used to have to take the nozzle off, run it so water streamed out, then put the nozzle back on, and it was good for one spraying - let up on the trigger, and it would have no pressure after that. Take nozzle off, let it stream, and good to go for one use...

This sticky valve was the problem, took me longer to type this than to fix it. Search internet for diagrams and simple instructions if this is your problem. The one pump style of theirs is really bad at this.

--->Paul
 

[George Marsh]

Bill,
I would think that if you are starving a pressure washer, it would make air bubbles.

If I don't purge the water hose before starting the washer, it stops until the air is worked out of the pump.

Every 28 inches of water column will make 1 psi. You may need to raise your tank. Can you add air pressure to your storage tank?

I like using rotary nozzles. Have you tried them?

I never have less than 20 psi going to my pressure washer, so I can't say what happens with low pressure going to the pump.

Does your 1/2 inch pipe deliver 3 gallons per minute? Most pressure washers use less than that, 2 + gallons/min. Try increasing the pipe size.

Take a pump and boost the water pressure before goes to the pressure washer and see what happens.
LOL
George
 

[Bill from Scotland]

Thanks all for the advice. I am kinda tied with my water supply as its all plumbed into the house system unless I can get some sort of large storage tank and an auxilary pump. I will have a look on Ebay regarding booster pumps, I may be able to get a 1000 litre tank that I could use as a reseviour.
Bill
 

[dave2]

[Ken Macfarlane]

We've got one like that. The pump is just worn out from too many hours use. 3.5 hp gas model but our little 50$ 120 V electric puts it too shame. BTW the electric model claims to be made in the USA, not sure its its true or not. Its an off brand name that we bought at home depot on a door crasher.