Adjusting unloader

[MichiganPowerWashing.com 14]

Hi

I'm looking for some basic info on adjusting brand new unloader - THE RIGHT WAY ( using bolt hidden under top cap ). Should I use pressure tester ? Any tips , advice or links ? That's the first one that I have such a big pressure spike for a second when I relase trigger. I blow already one of my old hoses.

Thanks for any help

[Mountain View 14]

I'm not the most expert at this but; when the unit is running I held open the trigger gun and adjusted the unloader (via the nut on top) until I had the desired pressure measured with an inline pressure guage mounted right after the pump. I chose to set it around 3000 psi, the unit will go to 4k. I'm using a buffer tank so even when I'm using the pw, there is the "unloaded" 1k of pressure feeding back into the buffer tank.

[offduty 25]

A pressure gauge should have no bearing on a pressure washer, especially when setting the unloader. Use the correct zero tip for your machine(a #9 in my case) and start flowing water, adjust the unloader until there is no water being bypassed when you are pulling the trigger. You are now flowing the maximum amount of water your machine can flow. Pressure should be irrelevant.

[Mountain View 14]

I stand corrected. I didn't want to make it sound like I adjusted the unloader all the time, I only do it once then vary the tips according to what I'm doing. Your point about max flow is valid. I am now having one of those "duh" moments.

[Paul Kassander 26]

The set nuts that are below the spring are designed as stoppers to prevent the unloader from being tightened beyond its desired setting. If you have employees that think if they crank the unloader down more I will get more pressure then you will want to use them otherwise they really are not necessary. To set them just move them up to the point where the unloader is set and lock them in place so the knob cannot be tightened any further.

To set your unloader determine your max operating pressure you are going to achieve and size your nozzle accordingly (use a new nozzle). IE you want 2500 psi at 5.6 gpm then you want a #7 nozzle.

Install your gauge in line for setting the pressure. For a flow actuated unloader you will have to pull the trigger as you are setting the pressure for a trapped pressure unloader you do not have to pull the trigger. Then tighten the knob or nut to the desired pressure then squeeze and release the trigger to be sure there is no spike when you release the trigger. IE if it is set for 2500 the gauge should not go beyond 1-200 psi above that when the trigger is released, if it does you have it tightened down too far.

From that point if you want to drop the pressure your best method would be to use a larger nozzle and not mess with the unloader. If you back the unloader off to drop your pressure and do not use a larger nozzle all you are doing is reducing the flow rate.

Also note that some unloaders require a certain amount of water to be running through the bypass line to operate properly. Remember an unloader is not a pressure building device it is a pressure regulating device it is designed to relieve (bypass) the water at a certain pressure that is all.

[PressurePros 248]

I set my machines exactly the way Paul described. I don't want the machines set to their rated pressure. All that does is build the pressure spike in the line.

None of the answers I have read is wrong. I think the fireguy's way (Hello William) makes sense as well and is probably a different way of describing the same final effect.

[MichiganPowerWashing.com 14]

Thanks for all the input !