I thought I would start blogging about safeties to pressure washers that should be a must in this day and age for everyone to review to ensure that the operator is safe when operating the unit and that major damage isn’t caused to the pressure washer.
All pressure washers come with unloader valves or as some people call them bypass valves. These devices are a MUST on all Pressure Washers as they set the pressure on the pressure washer without an fluctuation. They can also help turn the pressure on a pressure washer down and then back up again.
Having said that there are 2 x types of unloader / bypass valves that come on pressure washers and I will explain the differences below.
The most common valve used on pressure washers is a High Pressure Valve. Firstly high pressure valves are a lot cheaper to use on pressure washers, secondly they can be dangerous if the pressure washer isn’t operated correctly and they can also cause damage the pump and bypass / unloader valve on the pressure washer as well.
A High Pressure Valve holds the pressure of the pressure washer when in operation BUT when you release the trigger on the pressure washer the full pressure of the machine is kept in the high pressure hose that connects to the trigger on the machine.
The first problem with this high pressure unloader / bypass valves is that if the operator pulls the trigger on the pressure washer the gun and lance will kick back and has been known at times to hit the operator in the face and injure them. This is where both hands need to hold the gun and lance when you pull the trigger so this doesn’t happen.
The second problem with a high pressure unloader / bypass valve is that if your machine has an automatic stop/start system and you have a leak in the gun, the trigger doesn’t completely shut off the flow and the pressure washer will start surging or pulsating as with a leak the machine thinks that the pressure is being released and the trigger is being pulled so it is constantly trying to start up. Having this problem and if not fixed up and is left constantly doing this, then this will damage the internals in the pump and the bypass / unloader valve costing a lot of money. If you have a machine (which unfortunately most pressure washers do have this high pressure device on it) and it is leaking and pulsating or surging, I suggest you get this looked at straight away to avoid further damage to the pressure washer.
The second unloader / bypass valve is a Low Pressure or Zero Pressure Valve. This device doesn’t hold pressure in the high pressure hose when the trigger is released, so when you pull the trigger again on the unit you get a slow build up of pressure instead of the kick back that you would get from a high pressure unloader / bypass valve.
If you have a low pressure unloader / bypass valve and you have a leak on your gun or lance, the machine won’t constantly think that it needs to start up as there is no pressure in the line. The pressure washer doesn’t surge or pulsate and it doesn’t damage the pump and bypass / unloader valve on your machine all because you have a low pressure – zero pressure unloader / bypass valve.
Having a low pressure – zero pressure unloader / bypass valve increases the life of the pressure washer and is safer for the operator as well.
And thirdly to the above, which ever unloader / bypass valve device you do have on your machine. We find that no matter which one you have, if you “machine gun” (are rapidly pulling the trigger on and off) you will very quickly damage the bypass / unloader valve and also damage any hose reel swivels, link hoses, etc that are between the trigger on the pressure washer and the bypass valve. We always recommend to find what you are cleaning, pull the trigger and have the trigger constantly pulled while cleaning that area and then release the trigger when finished.