The purchase of a hot water high pressure cleaner should be seen as an investment in your business, and as such, the machine should be looked after and maintained as one would any other valuable asset.

A diesel fired hot water high pressure cleaner is very much like your motor car. It has a fuel tank, a fuel pump, fuel filters, an ignition system and an exhaust system. If you do not maintain these correctly, or use any form of contaminated fuel to run the system, you can expect the unit to fail, likely when it’s needed the most.

Boiler maintenance should be done by a qualified technician at least every 500 working hours. Here are some quick tips on what should be covered.

Check fuel quality. This can be done by draining a sample from the plug at the bottom of the tank where contamination will usually settle. The fuel must be clean. Drain and replace if necessary. In extreme cases, the tank may have to be washed and thoroughly dried before new fuel is filled.

Check the fuel filters. Some machines will have two, one which acts as a water trap and dirt filter and one which is a dirt filter only. Drain, clean and/or replace where necessary.

Open the top of the boiler and check for soot build-up
A wire brush can be used if there is not too much contamination in conjunction with a vacuum cleaner to remove the excess. If the boiler is badly sooted it will likely need to be removed and pressure cleaned.

Check the condition of the electrodes, clean and reset as required. Remember the distance between the electrode tips and the exact positioning of the electrodes is critical for the correct performance of the boiler. Refer to the service manual.

The fuel nozzle should be handled carefully. Care must be taken not to contaminate or damage the nozzle tip as this will have a negative effect on the flame pattern. If the diesel fuel was found to be unclean this nozzle may have to be replaced. It is essential that you replace this item with exactly the same OEM part.
Once reassembly has taken place and you are ready to test run the machine remember to check and if necessary set the fuel pressure on the diesel pump. You will need to refer to the service manual for this information as it varies from machine to machine.

Connect fuel pressure test gauge to the diesel pump and test. The gauge pressure should not fluctuate as this would indicate a problem with the problem exists with the pump. Pump pressure will vary according to operating altitude. Machines are factory set for sea level use.

Once the fuel pressure has been set correctly the last check would be done with a smoke pump. This is to determine the air and fuel mixture ratio is correct. Refer to service manual if unsure.

Set the air ratio on the intake side of the boiler until a correct reading is obtained from smoke pump tests.

Some tips to prevent premature failure:

  • Always use a dedicated clean container for filling diesel into the machine. Dirty fuel can cause immense damage to the boiler system.
  • Use an authorised water softener particularly if you are in a hard water area which can be obtained from your machine supplier. Doing so will ensure the build-up of scale within the heating coil is kept to a minimum and will speed up the cleaning process should this become necessary. Keep in mind that this feature is not always available on all models of machine.
  • Cool the boiler down at the end of a work cycle by switching off the heating system and running the unit for a minute or two before shutting down.
    Close the chemical suction at the same time if your machine has this feature, to avoid leaving detergent in the system.
  • Train the operator in the correct use of the machine.