[michael papworth]

Hiyya Ya'aal,

I've hired a 6.5 HP honda powered pressure washer. It's got a 3 cylinder brass pump. I'm not sure of the manufacturer, but it's a small industrial machine.

It's got a 1505 jet fitted in an RS30 lance.

Now then. It cleans the paving slabs and block paving bricks absolutley fine - but leaves the weeds completely.

Years ago I had a small domestic machine that did the same job just as fast and stripped out the weeds with no problem.

What's going on here?

Is the machine lacking power?

Is this normal for a 1505 jet?

Would a fsc (flat surface cleaner) do a better job and strip out the weeds?

I need to know as I have a big job coming up on Weds and will need to hire an fsc if that's the route to go. The job is a pretty large patio with a few weeds here and there between the slabs. I don't want to be having to get them out by hand!

[Kevin R]

Depends on the weeds Wally.

The easiest and best way is to pop around the week before with a weed killer.

A flat surface cleaner would not do a better job

what psi or bar is the machine?

[Frank pole]

thats totally normal! if the washer is running a 1505 jet then the pump will be 200bar x 15lpm ish - powerfull machine! but as the man before me said - if you have a patio job thats got loads of weeds then always apply weed killer at least 48 hours before starting job - hope this helps!"£$%

[michael papworth]

Hey Frank! Spot on with the machine spec, m8!

Thanks for the advice, guys.

And would weedkiller loosen the moss as well?

What's all the fuss about fsc then?

[Frank pole]

With patios & block paving weeds are your worst nightmare! moss, lichens & algae will come off almost instantly with a good lancing!

[Kevin R]

The FSC is excellent for block paving as it doesn't blow the sand out of the joints as much as a lance. Its also quicker over a large area and less messy 

[poleman]

Water flow is a facture! A good pressure washer to work at full power would need a max flow rate

[trevor perry]

if i was you i would clean first with the fsc any weeds that dont come up then i would  remove these  with a turbo nozzle

[michael papworth]

With patios & block paving weeds are your worst nightmare! moss, lichens & algae will come off almost instantly with a good lancing!

Yes. I'd noticed that moss by itself came out quite easily. Where itwas mixed with weeds, it was a nightmare.

General concensus seems to be moving towards a turbo nozzle just slicing through weeds. Is that right?

[LWC]

fsc's are brilliant 

we did 2 tennis courts once, worked a treat

[michael papworth]

I've just found a web site with a nozzle calculator.

The idiots in the hire shop gave me the wrong lance.

A 1505 nozzle is for a 4000 psi 15 lpm machine.

The one I have is 2000 psi and 10 lpm.

I should have a 1503 nozzle!!

Oooh. Am I going to make an angry phone call in the morning. I've spent an entire day pratting about with a machine with the wrong nozzle - and it has the effect of reducing the pressure to something like a half of what it should be!!!

THAT'S why it appears to be under-powered. It's over jetted!

[poleman]

www.youtube.com/watch?v=I0wTz4HMHkA

[Glyn H]

A 1505 nozzle is suitable for 140 bar (2030 psi) @13.4 litres per minute

which is close enouth not to cause a loss in pressure

[karygate]

i use a turbo nozzle and it shifts anything  including weeds.but am running a 13hp 4500 psi though.

[LWC]

www.youtube.com/watch?v=I0wTz4HMHkA

tools!