It is a common mistake to view a washer with a high pressure rating as being a better option. A pressure washer should be selected based on what it is expected to clean and not on its pressure rating alone. Whilst using cold water under pressure is adequate for most cleaning jobs hot water does give extra cleaning power for stubborn dirt like grease and grime. Some cold water washers can be used with hot water perhaps supplied by a separate heater for added cleaning power. The maximum inlet temperature indicates the level of hot water the machine can take.
Hot water pressure washers are also available with electrically heated boilers which offer limited temperatures. These machines are normally used where using kerosene is not an option. Deciding on which pressure to buy or hire is complex. This relationship between water flow and pressure is important depending on the type of cleaning being carried out. Reading the technical specification of a washer is fine but is the pump of good quality? Is the hose of the correct rating for the machine and is it long enough for your needs?
On industrial machines it is normal to use a slower revving motor with a larger pump which means it can be used for longer periods without overheating. Pressure washers can be powered in various ways and each has its advantages. Electric power is the most common source with smaller motors using a 240 volt single phase supply from a conventional plug socket and larger commercial machines using a 3 phase 420 volt supply.