When you buy a high-pressure cleaner, you are not just buying a piece of equipment, you are investing in your business, writes Pascale Pillay, technician at Hawk Pumps.
UNDERSTANDING the features of your high-pressure cleaner and some simple safety precautions is vital to ensure the longevity of your investment.
Often the person purchasing the high-pressure cleaner, is not the person who will be using it. The operator does not have any vested interest in the unit and while they may have received some training, they will often by-pass safety features. It is important that only well-trained operators use your equipment and do not take short-cuts that could damage or shorten the life span of the machine.
Hawk will train your operator, free-of-charge, at the factory in Durban or Johannesburg by appointment. If training is required at the operator’s premises, a charge will be levied.
Water inlet filter
High pressure pumps are designed to pump clean water from an adequate supply (double the displacement of the pump).
Hawk high pressure washers are fitted with water inlet filters as a first line of defence to reduce the possibility of dirt and grit getting into the system.
It is common for operators to by-pass the filters in the case of units with header tanks, by removing the lid of the tank and feeding the water directly into the tank or by removing the strainer element. It is vital that the water in-let filter is not by-passed and must be checked and cleaned daily, before each use, to avoid clogging.
A dirty filter will cause cavitation and dirty water can result in the valves being scored and the seals destroyed. A clean filter assures good performance of the machine!
Hawk high pressure washers come standard with a header tank for all units delivering an output of more than 15l/min. For those units that provide outputs of up to 15L/min, a header tank is available as an optional extra and should be considered if your water supply has a low or inconsistent pressure and flow.
The header tank is fitted with a float valve, and for electric and electric start (petrol/diesel) units, a low-level cut-out switch which automatically switches the unit off if the water level in the tank is too low, protecting the pump from cavitation. Cavitation will result in the burning of the pumps seals, shattering of the ceramic pistons and breaking the conrods.
In the case of header tanks that have lids, another common problem is for the lid of the tank to be left off (often lost) allowing dirt to settle in the tank and get sucked into the system.
It is important to check the oil level frequently and the quality of the oil. If the oil is dirty it must be drained and replaced. The first oil change must be carried out within the first 30 hours of working. Change the oil every 300 working hours, thereafter, or at least once a year. (a car running at 60kph for 300 hours travels 18000 km)
If the oil is milky, it means that water has mixed into the oil and the cause of this must be investigated immediately and resolved before using the pressure washer. Possible causes could be that the environment is too humid and water in the atmosphere is being pulled into the space above the oil. Another reason could be a water leak internally.
Many people think that the unloader valve is responsible for creating the pressure output of the high-pressure washer. This is not the case. The unloader valve protects your high-pressure washer from over-pressure spikes.
It’s actually the nozzle at the end of the gun and lance that determines the maximum pressure that may be obtained. If the nozzle is worn or too big to start with, pressure cannot be achieved. Often operators will tighten the unloader in an attempt to achieve the correct pressure, but this won’t work. When the unloader has been screwed too far down, and the gun is then closed, the pressure will spike very high before the unloader valve can dump. This will damage the pump and could even burn out the motor.
The Unloader Valve is set at the factory and should not be tampered with or overtightened.
When the high-pressure washer is running but the gun is closed, water will keep by-passing through the system, getting hotter with each cycle. This is can lead to the seals in the pump melting and cause great damage. For this reason, the unit should not be kept running when it’s not in use.
For applications where the operator will be using the machine intermittently, we recommend that it be fitted with a “total stop/start” which is available as optional extra.
When the operator intends to stop spraying, the unit can be switched off by shutting the gun. The operator can then switch the unit back on by simply pressing the gun trigger. This conveniently saves the operator from having to go to the unit and switch it on and off between uses. Unfortunately, many operators won’t bother to do this and rather leave the unit running during periods of inactivity.