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Unloader valve wont go in to bypass mode - Dewalt Pressure Washer. 4200 PSI 4.0 GPM Pro Triplex Pump Gas

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What is a bypass unloader


According to epowerwash.com:
"The unloader valve diverts water flow into bypass when the trigger gun valve is closed. Unloaders may be designed to respond to either an increase in pressure or a change in flow. The unloader valve may also be used for variable pressure adjustment."

More information here:
All About Unloader Valves ePowerWash

Jun 06, 2014 | Alfred Karcher Pressure Washer

1 Answer

Honda XR 2600 pressure washer, cord will not pull on engine


This is typically due to the unloader bypass valve not operating properly. You can remove and clean this valve or you may want to replace the valve with a new one.
If you take the high pressure hose off of the pump and with the water turned on you can start the engine each time then you probably should replace the unloader bypass valve.

Here is a link to the pump.

http://www.allpartsinc.com/mmAllParts/Others/A14292-001.pdf

Oct 08, 2012 | Honda Maxus Pressure Washer MX5222

1 Answer

Motor on my K5.55 pulsates noisily when not spraying water but stops noise when spraying water, any ideas? Regards Pete


Hi Pete and welcome to FixYa, I am Kelly.

When the trigger on the wand is off the unit has an unloader / bypass valve located on the output side of the pump that cycles to bypass the output pressre back into the inlet side of the pump so it does not dead head and destroy itself. I suspect that you unloader bypass valve is traveling to one extreme and stem is resting against the pump body after you release the trigger. You will not hurt it by continuing to use it but you want it to stop you will probably have to change the unloader / bypass valve. If you do change it make sure to lubricate the housing and seals with WHITE grease before installing. My thoughts... it makes noise but it works. You choice as to how to proceed.

A second thought... is that the motor isolation mounts may be getting torqued when the hose is fully charged and the motor touches the chassis.

Searcing Karcher.com, espares and cleanstuff did not result in me finding your unloader valve. They do have a cyliner head....

Thanks for choosing FixYa,
Kelly

May 02, 2011 | Garden

1 Answer

Craftsman gas powered pressure washer kills motor when you release wand trigger.


The unloader/bypass valve is jamming or defective. When you are not pressing the button the water is directed through the unloader valve/check valve to recirculate.It is common for them to corrode or for the spring to break.If it has an adjustment screw on the unloading valve for unloading pressure make sure you count the turns before disassembling it to make sure you dont over pressurize it.It is not opening causing the engine to choke out.Please let me know if this helps

Jan 19, 2011 | Garden

1 Answer

Coleman model APW-120 May have frozen while stored over winter the unit is new but water was not completly removed before storage. Problem motor runs continuosly but there is no water pressure I have...


Whar has happened is that your unloader / bypass valve is sticking. This is due to minor corrosion and having water in the unit over the winter. Most of the time they will sanp out it if you do the following:

Add 3 - 4 oz of oil into the water supply connection and briefly and I mean very briefly switch on the unit then right back off. Add more oil to the water supply connection and then let it sit overnight.

Then next day turn the unit on briefly and let it sit another 30 minutes. After this you connect all hoses making sure to purge the air our of the supply hose BEFORE you connect the to the unit. Then once you turn the unit on rapidly trim cycle the wand trigger. Your goal here is to cause a water hammer of the unloader / bypass valve to get the spring and cupped seal to move in the housing. Pause briefly and see if pressure builds then fan the wand trigger again. This can take a few minutes to get it to work but the routine of pausing waiting momentarily and rapidly tripping the wand trigger is what should get the unit going again.

If this does not work you will have to take the unit apart dis-assemble the unloader / bypass vavle on the output side of the pump and remove the corrosion on the spring and the housing.


Once your done cleaning up the bypass unloader valve before you put it back in the housing place a liberal amount of Lubriplate #105 White Grease on the spring and inside the housing on the mating surfaces. (#105 white grease is available at any Auto Parts store. It is in a 3 - 5 oz plastic tube)

Re-assemble the unloader / bypass valve an it should work like a champ.

Thanks for choosing FixYa.

Kelly

Sep 16, 2010 | Coleman Powermate DuraBuilt 1400 PSI...

1 Answer

II lost High Pressure while washing I laid the gun down the time cut it off aand I reseted it and had no high pressure I removed the pressure adjuster and noticed it was rusted I cleaned it and replaced it...


The pressure adjuster you are talking about is actually your unloader which is a pressure relief valve. It is normal for this to pop up and down as it moves in and out of bypass mode. Your pressure issue could be a failed unloader, valves or packings in the pump. You will need to bypass your unloader valve to find if the issue lies in the pump or if it is simply a failed unloader. If you have any questions, need parts or service, please feel free to contact me using the information below.

Sincerely,
Aron Kerr
Landa Northwest
800.247.8103
503.255.6508
www.landanw.com

Aug 17, 2010 | Honda Landa PG 3500 PSI Pressure Washer

1 Answer

High pressure won't return when triggered


If you unplug the tip, will it work? If so, unloader valve is sticking.

Jul 06, 2010 | Karcher 2500 PSI Pressure Washer

1 Answer

K5.140 makes a revving noise when releasing the


Before you do the below steps check the water supply inlet screen for obstructions where the water hose connects to the unit. If you notice debris remove and clean the screen under running water with a small NYLON brush.

The bypass unloader valve is triggering earlier than it should. You can lubricate this by adding oil to the water supply inlet (at least 3 oz.) and very briefly switching the unit on then off 0.5 seconds. Then let is sit overnight. The next day connect power briefly and again cycle the unit on then off for 0.5 seconds. Connect the water supply and then purge the water wand hose into a bucket to catch the oil before use. After this restart the unit and operate the wand trigger under full pressure at 0.5 second intervals to ;scycle the bypass / unloader valve inside the pump. This method has worked in about 95\0 % of the machines I have worked on. The oil lubricates and fattens the seals in the bypass / unloader valve. It eihter works the first time or the seals are torn in the unloader valve and must be replaced. With only 3 uses I think your pretty much in the clear and will not need new seals.

Thanks for using FixYa.

Kelly

May 16, 2010 | Alfred Karcher K 5.93 M Electric Pressure...

1 Answer

Red light on power cord stays on powerwasher wont turn on


The red light means you are getting power. It sounds like the bypass (unloader ) valve is stuck. This is inside the actual pump

Sep 12, 2009 | McCulloch FHH18A Electric Pressure Washer

1 Answer

When I release the trigger it "idles" fine, but when I re-engage


I have seen this problem alot and it can normally be rectified by clean out your unloader/bypass valve the orings on this valve get damaged as jerr said by leaving hoses and trigger pressurised, the easiest way to test if it is a faulty unloader valve is to do as you say it does and when it is on its weak stream turn your nozzle to detergent or low pressure mode then back to high pressure it should kick the pump back in...

If you do not have low pressure(chemical applicator) on your nozzle you may be able to remove the front half of your lance to achive the same result...

Kind Regards
Brad

Aug 04, 2009 | Briggs & Stratton Power Products 1539...

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