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Karcher Pressure Washers - Useful Information

2K views 17 replies 7 participants last post by  Cashmere_Chris 
#1 ·
The key to pressure washer performance is a combination of pressure (bars) and flow rate (litres per hour). Imagine the fireman's hose - literally thousands and thousands of litres of water per hour but at 3 or 4 bar. You need good pressure - 120 - 140 bar and a decent flow rate - 350 - 500 litres. For the old school a bar is equivalent to 14.7 psi. Note that there is a difference to maximum pressure and rated pressure. Make sure when comparing fruit it is apples with apples.

Karcher pressure washers are sold in series - much the same as BMWs. They start at 2 series, denoted by K2*** (stars being model numbers, ie K2300, K2385, K2400, etc) through to 7 series, denoted by K7***. There is an 8 series but this is a hot water machine and not widely available in the UK.

The K2*** machines are opening price point and cover light duty work. For the serious car owner, with drive way, garden, patio etc, the K3 or K4 should be ample. There are a number of K3*** models out there, most are actually made in Italy rather than Germany - Karcher own a couple of factories there. There is also one K3* sold through Screwfix - made in China.

Look out for the "X design" - the latest range available for K3*** through to K5***, i.e. K3500X. These have water cooled motors are are therefore quieter to use.

B&Q have the only K6*** on the market, the K6.160, and these are on sell through right now. You can get the only K7*** from Makro if you have a trade card - K7280. This has a brass cylinder head so should last for ever.

Also conside the length of high pressure hose that comes with them. 4 metres for the K2 makes them cheap but means having to continally move the machine as you wash the car. At the top end you are looking at 9 - 12 metres!!!

The higher you go in the range the more cleaning applications are open to you. Look out for detergent handling capabilty, starts with a little tube that "sucks" detergent through, mixes with water and is applied at low pressure, either through the lance or brush. Higher specced machines will have on board detergent tanks - maybe even twin tanks.

Any questions, hehehe
 
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#11 ·
OK - first off for general car cleaning and the like the K3 series is as far as I would personally go. The K4, K5 and upwards will do the job marginally quicker, but Hey - we enjoy cleaning the BMW, right?

Here's the cautionary bit. If you buy a machine with a dirt blaster - that's the lance that looks like it has a walnut whip on the end LEAVE IT IN THE SHED. You do not and will never need this accessory for the car. A high pressure lance is all you need - that and a brush of course.

I would never get closer than 18 inches (450mm) to my car with a HP lance - give special caution to parking sensors and also to tyre valves, these are the most sensitive areas on your car. Also be careful cleaning under wheel arches - don't be tempted to poke the lance under the arch and wave it about. The paint inside wheel arches is NOT the same as exterior / bodywork paint.

I hope this answers your questions so far Guys.
 
#14 ·
Unfortunately some of us have learned the hard way.

  • For a laugh (yeah right) I put my finger over the end of the HP nozzle - took about three weeks for the skin to grow back.
  • Once, when I was demonstrating a sand blaster accessory on QVC I managed to strip the suede off the toe of my Caterpillar boots.

Never too old to learn!!!
 
#16 ·
The sand blaster attachment connects to the trigger gun, just like any other accessory.

The is a shorter hose with a hardened end that you "bury" in a bucket of silica sand. The sand is drawn through the hose (via the international gift of the venturi effect), mixes with water and out through the lance complete with special nozzle. Hey Presto - wet sand blasting.
 
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