That is a good question with a not-so-easy answer.
‘You should replace it when it is worn’ is the easy answer. But how long do they last?
Most operators have an attitude of ‘If it ain’t broken, why fix it?’, but what they don’t realize is that if a nozzle on a pressure washer wears away (and they do) by a small margin, you will experience an amplified drop in pressure and cleaning capacity, which means:
- Longer cleaning (waste of time, increase in cost)
- Less efficient cleaning
If a pressure washer’s nozzle’s diameter increases by as little as 10% due to wear, you will experience a 21% drop in pressure.
But how often do you need to replace a high pressure nozzle?
That depends on:
- The water quality (mostly dissolved minerals which will wear the nozzle faster)
- Your operating pressure
- The amount of use
These three factors will wear away a nozzle at different rates. The easiest way to know if a nozzle is worn, is look at the operating pressure on the pressure gauge and recalling what it was when the unit was new. If there has been a 10% or more drop in pressure, it is time for a new nozzle. And when a nozzle change doesn’t make a difference, then it may be time to refurbish or replace the by-pass (unloader) valve and only then would you bother changing seals on the pressure pump.
Quality HAWK pumps would usually not need to have seals changed before 500 – 1000 hours of operation (working 4 hours a day, 5 days a week, that means 6 -12 months). And 500 hours would only be in extreme circumstances where really dirty water is used, proper water filters are not in place or the pump was starved of water or oil and sustained some damage.
So, when your pressure washer’s pressure drops, replace the nozzle. It is a consumable item and should be changed regularly for top performance and effective cleaning!
Lastly – you can’t just replace your current nozzle with ‘any old nozzle’! Nozzle size on pressure cleaners is very important. If you go one size too big, you may experience a drop in operating pressure as much as 500 PSI. If you go one size too small, you unloader valve will go into by-pass mode (partly) and wear away faster which will cost you money!
Where do you find the size of the nozzle of you high pressure cleaner?
It is usually printed on the side of the nozzle. If it becomes illegible, you will have to tell your supplier either which pressure washer model you have, or alternatively give him your pump specifics:
- Operating pressure when new (not maximum pump pressure) and
- Flow rate in litres per minute (usually printed on a sticker on the pump).
He can then look it up on a table to see what the nozzle size should be. Then buy a couple of spares to keep handy!
Which type of nozzle is best? Click here to read the Article: Choosing the right Pressure Cleaner Nozzle for your job