Karcher pressure washer not working properly.

[Ian_Edwards]

I have an old pressure Karcher pressure washer which must be at least 20 years old.
It was working OK when I used it in early October, but today it's not producing pressurised water.
The pump is still running, and pumping, but the pressure is no more than mains water pressure.
Is there anything I could obviously check before I consign it to the skip and buy a new one?
It's always been stored in a heated garage and run on mains water.
A long shot question, given it's age it may just be worn out.

 

[sarabande]

Is there an air bleed screw ?

Something like this...

 

[jamie N]

As you'll know, it's a diaphragm pump and I'd imagine that either one of the valve's simply 'stuck', or the diaphragm has 'perished' and isn't allowing pressure to build up; similar (in my mind) to a hole in the heart scenario. Not tricky to repair if you've the bits, and can be faffed.

 

[Bouba]

Sometimes the jet in the lance gets calcified.....pouring vinegar in and letting sit overnight can cure. On some jet washers, the piston is actually made of plastic, and can easily break or melt....always go for a jet washer with metal piston....same thing with cheap compressors

 

[PetiteFleur]

Sounds like mine, although not a Karcher - I have to hold the trigger before switching on the motor, then it works but stops when the trigger is released. Have to repeat before starting again...

 

[alahol2]

I've fixed the one I use. It was the pump that had a problem with the valves. Spare parts are available and, I'm fairly sure, there are videos on youtube showing dismantling, repairing and re-assembly. At the price of a new, decent, one it's well worth trying to fix.

 

[AntarcticPilot]

The valves are plastic and don't last forever. It may be scrap. Replacement valves are available, but at a price that makes it almost cheaper to buy a new one!

 

[rotrax]

As you'll know, it's a diaphragm pump and I'd imagine that either one of the valve's simply 'stuck', or the diaphragm has 'perished' and isn't allowing pressure to build up; similar (in my mind) to a hole in the heart scenario. Not tricky to repair if you've the bits, and can be faffed.

Are you sure it is a diaphragm pump? Just taken another make in bits and it has a piston pump. As did several steam cleaners/pressure washers I repaired in the past.

 

[europe172]

I have an old pressure Karcher pressure washer which must be at least 20 years old.
It was working OK when I used it in early October, but today it's not producing pressurised water.
The pump is still running, and pumping, but the pressure is no more than mains water pressure.
Is there anything I could obviously check before I consign it to the skip and buy a new one?
It's always been stored in a heated garage and run on mains water.
A long shot question, given it's age it may just be worn out.

On mine there is a system that enables motor power when water pressure is present, it is a small valve which acts on the switch, if you can safely take the switch box apart and have a look ( but try bleeding it first)

 

[WoodyP]

At 20 years old l wouldn't waste my time with it. I see that Aldi have a pressure washer coming up this week. I had one that did stirling work. At under £100 it's excellent value.

 

[jamie N]

Are you sure it is a diaphragm pump? Just taken another make in bits and it has a piston pump. As did several steam cleaners/pressure washers I repaired in the past.

I was fairly certain when I thought about it, but with hindsight can't absolutely confirm whether it was, or whether it was a different make. Apologies if my original post was incorrect.

 

[HunterWanderer]

Is it leaking from inside? If so its probably frost damage.
Mine froze last winter and split the discharge fitting. They are available on line and easy to change.

 

[Ian_Edwards]

Thanks for the replies.
From the Karcher info' I've found online, it's a 3 cylinder bent axis pump. It uses a swash plate, sometimes called a wobble plate, to compressed each cylinder in turn against a spring.
The valves may be worn, as already suggested.
There seem to be spare parts available, the aftermarket ones look to be low cost but a complete Karcher supplied pump is close to the cost of a complete new unit.
It's probably worth taking it apart and seeing if the is anything I can fix.
If I make a mess of it, I've lost very little, except some time.

 

[wonkywinch]

Thanks for the replies.
From the Karcher info' I've found online, it's a 3 cylinder bent axis pump. It uses a swash plate, sometimes called a wobble plate, to compressed each cylinder in turn against a spring.
The valves may be worn, as already suggested.
There seem to be spare parts available, the aftermarket ones look to be low cost but a complete Karcher supplied pump is close to the cost of a complete new unit.
It's probably worth taking it apart and seeing if the is anything I can fix.
If I make a mess of it, I've lost very little, except some time.

After my second Karcher failed this way, I switched to Nilfisk. Had it for maybe 10 years with no problems.

 

[andsarkit]

I have a 30 year old small Karcher that still works as it has a metal pump. Two later Lidl and Karcher ones lasted about 3 years each as they had lightweight pumps using a lot of plastic.
You can replace the pump seals cheaply and Karcher spares are available. Youtube videos are available.
The pump pressure cut off is a mechanical lever operating the switch and this can stick but if the motor is running this is not the fault.
I now have a Nilfisk which is nearly twice the weight and should see me out. If you can pick up the pressure washer in one hand it is probably not built to last.