Re: Problem with pressure washer

I have a Karcher K 6.85 M pressure washer that has developed an

> apparent fault: > > When using the Vario Lance that came with the unit, as soon as I turn > the pressure above 3/4 of the max, the unit starts to pulsate, i.e. it > works in fits and starts, works fine for a few seconds, then it stops, > and starts working fine for a few seconds again. > > > It works fine if instead of the Vario Lance I use the Dirt Blaster > (rotary pencil jet) > > The closest reference in the Manual is: > > "Strong Pressure Fluctuations: Clean high-pressure nozzle: Remove dirt > and debris from the nozzle bore, using a needle and rinse through with > water > from the front". > > > But, in my case, there was no dirt in the nozzle. > > > The unit has been used little. It worked fine a few months ago.

I would check for a problem with the supply first. If the supply hose is kinked or your supply flow is poor then the pump will pulsate like this.

Tim

Reply to
Tim Downie
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But then it wouldn't work OK with the other lance either.

Reply to
The Medway Handyman

I bow to your greater knowledge of lances. I just know that with mine, if it's on a high flow setting, if the tap isn't turned on fully, the pump pulses as the input pressure drops below the minimum required.

Tim

Reply to
Tim Downie

Oh it will, but then all lances would display the same fault.

Reply to
The Medway Handyman

Only if they allowed the same volume of water through. If there were small differences then a "high flow" lance might cause pulsing whilst a low flow one wouldn't .

Tim

Reply to
Tim

HPC's use a positive displacement pump. The flow rate is fixed.

A lance can only affect the pressure, not the flow.

Reply to
The Medway Handyman

There we are 2012 rides again. I blame Google. Brian

Reply to
Brian Gaff

--------------Snip All!----------

Just to let you know your full stop button isn't working! ;)

Reply to
The Other John

I had a similar problem on mine. After much investigation on my part, I came to this Group (UK.D-I-Y) who diagnised the problem as a faulty O-ring inside the machine (causing a tiny leakage in the pressurised water course inside the machine).

Replacement of the O-ring proved to be impossible, and I bought a new pressure washer: I had reached the tipping point between "cost of a new one" and "hours that have already been spent, and may yet need to be spent, trying to fix this".

J.

Reply to
Another John

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