Just a quick tip when buying electric or petrol driven pressure washers, regarding the manufacturers statements about their pressure and water flow. This is a simple explanation of how some details are mis represented - please read on!

For effective cleaning of anything you must have a good mix of pressure and water flow. Imagine taking a shower with a high pressure pencil jet of water on you - lots of pressure but no water to rinse with. Now take a shower with someone pouring buckets of water on you - lots of rinsing but no concentrated cleaning power.

So you need a healthy combination of pressure and flow for a machine to work.

Manufacturers will often quote 2 pressure figures; here is a quick explanation.

Working pressure (or rated) : quoted in psi or bar, this is the important one. This is the pressure that will be delivered when the machine is working. If it is not quoted, please ask your supplier, as it may be very low and they may be intentionally hiding it from you!

Maximum pressure :  All pressure washers have a point at which they go into standby, bypass or shut down eg. when trigger is released, or system is blocked etc. This is the pressure at which the machine stops working! You cannot achieve this pressure for working, so it is a completely useless figure for the operator! Don't be tempted by these big numbers when comparing machines. I have seen several adverts that quote over 2000psi max pressure in big titles, then when you check, the max working pressure is only 1300psi!

Flow rate : generally quoted in litres per minute (l/min) or per hour. Make sure you do the comparison correctly. Here is an example

Washer 1   -  16.6 l/min - doesn't sound exiciting does it.

Washer 2   -  700 l/hr - woohah! loadsa water

Work the conversion and washer 1 is producing 1000 litres per hour! (16.6 x 60 min = 1000) Much better than number 2.

Its also worth remembering that if you are buying a machine for on-site cleaning, away from a mains water source, check how much water you will need - you may be surprised. Machine 1 will eat a 25L container every 1.5 minutes!  

Well I hope this helps someone - happy shopping!!