unloader for pressure washer

[Donald]

I bought a used electric hot water pressure washer last fall for a good price. It was not working although the pump had been replaced. I took some of it apart and was half convinced it was the unloader. Its an adjustable unloader and I took it apart and inside it looks clean, no corrosion or obvious wear. But I get almost no pressure with the pump turned on. I am trying to figure out what could be wrong with the unloader besides a lazy spring.

Today I connected up the trigger wand with an inline pressure gauge direct to the output of the pump (no unloader). Keeping the trigger pressed, I turned on the pump and walla, 1000 PSI of pressure water. Its a 1000 or 1200 PSI machine. I guess I will get a new unloader, but just cannot see what is wrong with the unloader. The unloader is about $80, but given what I paid for the non-working hot water pressure washer, its still a steal.

But I still need to make sure the coils and burner work.

 

[Carbon]

What is an unloader in this context? It sounds like something that would take the pressure off of the hose after you shut off of the pump, but I don't think that is what you mean. It sounds as if you may be referring to the valve on the wand.

 

[vaboom123]

That's what it sounds like is causing the problem. I believe the unloader valve is the spring type mechanism that's inline with the pumps output. I got a free gas pressure washer and am having the same issue. That's the only thing I can think of not allowing the pressure to be up to par. I also took mine apart and played around with it not having much luck.

 

[Donald]

The unloader is not like the unloader in an air compressor that relieves the pressure after shutdown, so startup will be easier.

Its designed to open at say 3000 lbs and recycle water back into the inlet of the pressure washer, mainly when the trigger is let go and the pump is running. You either need that or some way to turn an electric pump on and off. Small electric ones do that.

So I would say all gas pressure washers much have one. Could be built in. Mine is an external one and adjustable.

Water comes in one end from the pump and goes out the other end to the hose/wand. There is a side tube coming off that goes back into the inlet of the pressure washer (where the garden hose is).

Otherwise when you release the trigger, pressure will instantly build up and damage something.

But this is only a short term solution to the pressure problem. The water going round and round heats up quickly and in a few minutes the heat will damage the pump as there are plastic or nylon parts inside.

 

[Donald]

Originally Posted By: vaboom123
That's what it sounds like is causing the problem. I believe the unloader valve is the spring type mechanism that's inline with the pumps output. I got a free gas pressure washer and am having the same issue. That's the only thing I can think of not allowing the pressure to be up to par. I also took mine apart and played around with it not having much luck.


Bypass the unloader, tape/tie the trigger on and start the engine and see what happens.

 

[Donald]

I took the unloader out again today. When I blew through the inlet and had my thumb over the outlet and air came out the bypass hose as if the unloader was a tee.

I took it apart even more than I have before and found one part that needs a little polishing. I did that and put a dab of grease a few places and now I get some pressure with the unloader in the flow.

One part that acts as a valve has an area that looks rusty. Pretty smooth but rust colored.