[A+CleaningService]

Is 2000-2800psi  any good for washing.Driveways etc?

[kordun]

ok, but 3500 and over is better

[Andy Foster]

I have been cleaning drives etc for 5 and a half years now using a pump which cleans at 2500 psi and 14ltrs per minute flow rate.

Never had a problem.

Andy

[Nathanael Jones]

You'll clean with a smaller machine, but it will be slower and I would recommend a turbo nozzle for real results.

Bigger machine = easier and faster with higher earnings. Its a no-brainer for me!

[Andy Foster]

As long as the flat surface cleaner is set up to work with the flow rate and pressure of your pump then bigger does not necessarily mean better I'm afraid.
Turbo nozzles have their place in the tool box, but they are incredibly messy and not suited to all jobs.

Also, if you are going over 3000 psi and still on a petrol engine, then you could be running a pump on an underpowered engine. 

Going over 3000psi is where you need to start looking at a diesel engine (costs start to spiral at this point).
If you are running the machine 8 hours a day 5 days a week, then either stay below 3000psi on a petrol or go diesel and go for over 3000psi.

Everything starts to get more expensive when the pressure ramps up... hoses, triggers, nozzles etc so make sure it will pay you to go big.
There are some petrol engine driven pumps that claim to be 3800psi or  more... read the description carefully as they will probably say 'effective' pressure or something like that which means that with a turbo nozzle, they will give out the equivalent of this pressure and not that ACTUAL pressure.
Again, this can put unnecessary stress on the engine.

Buy the machine from someone local to you so that they are the ones who are going to have to fix it if it goes wrong!

Just my experiences but hey, do what you will.

Andy

[Nathanael Jones]

There are a few good pumps rated to 4000 PSI that will work happily on a 13hp Honda GX390 engine. Most 4000 psi pumps sacrifice flow rate to achieve the extra pressure though, and you really won't notice much difference between 3600psi and 4000psi.

Personally I think 3000psi with a good flow rate is fine,.. many machines run at 17-18lpm,.. some gearbox pumps run 21 litres per minute @ 3000 psi on a 13hp petrol engine.

The important thing IMO is to get lances with quick connect interchangeable nozzles. You will need a turbo nozzle for cleaning really dirty concrete etc,.. but a turbo will damage softer surfaces, so a variety of "softer" nozzles and tools are a must.

I use an X-jet for a lot of my work which gives a spray barely more forceful than a garden tap,.. but combined with the right chems (And the fact that it practically doubles the flow rate of the machine!) it's a fantastic tool for cleaning roofs/gutters/painted walls/pebble dash etc or just pre-treating really dirty concrete.

Diesel engine machines are expensive (although my dad got a great deal on a 10hp generic on that's running great and has a 2 year guarantee) and really only for those who do nothing else but pressure washing.