Pressure Washer - Low Pressure

[jgbanshee]

I have a 2.5GPM pressure washer with Honda 5Hp motor and DeVillbiss pump. I turned it on to use and it worked for 1 min then the pressure quit and only sprays mist. I took everything off that I could to check for something clogging it and found nothing. Im not sure how i would tell if the pistions in the pump are bad but they looked fine to me. The rubber seals around the pistons are fine too. i checked the pressure adjustment and was never fiddled with. I am thinking about buying a new gun/wand and trying that.

[Lou_B]

As a guess, it sounds as if the pressure washer's suction is starved or a suction check valve is leaking.

With the engine off and the wand hooked up, try supplying water hose pressure to the pressure washer. Press the wand trigger and you should see a small solid stream of water. This verifies that there are no clogs that are limiting flow.

With hose pressure still applied, start the engine up and press the wand trigger. If you get a low volume spray, this indicates the suction check valve(s) are leaking or the piston seals are worn. Since you checked the piston seals, I'd clean the suction check valves and try again.

Your pressure washer worked OK for a while, so it is probable that junk is keeping one suction valve partially open. Hopefully this will be an easy fix!

Lou Braun

[jgbanshee]

Where are the suction valves and what do they look like?

[hhw]

Just a thought, I have a similar unit. Occasionally I will get in too much of a rush and either forget to purge the lines ( feed hose and wand hose) by allowing some water to run through the system under feed pressure only. When I do this I will get only a fine mist. I have to shut the unit down, and run feed water through until all the air is purged.

[MikeFromVA]

I have a similar problem that I was going to ask about. Here's what mine does...

When I start it, it works for a short time (less than a minute) and then only squirts water at regular hose pressure. I can only get it to "catch" by dropping the engine RPMs really low (almost to cut-off) while holding the trigger. At that point, the pressure aspect starts up again and I can raise the RPMs some. If I let go of the trigger and try to spray again, I have to repeat the steps. Also, I cannot use tips that allow a lot of water flow (above 25 degrees) as I can never get the pump to catch...

Test yours and see if the problem is similar. Anyone have ideas on solutions?

[tc18ny]

I think I have the same unit that I bought new at Lowe's. Same thing here. It'll work fine for a while then loss of pressure. I'll wait a minute, press trigger a few times, and it works fine again. Only happens once in a while, and not every time I use it. Weird stuff.

[jgbanshee]

I did buy my pressure washer at Lowes too. I cannot get mine to build up pressure at all.

[georgi]

It could be your water supply at your house. I have lived at two different places that the water supply could not keep up. Both places had well water. Those problems actually left a bad taste in mouth regarding pressure washers, and I was reluctant to buy one for myself (I borrowed the others). My new washer is great so far. It is the next model up from yours (I think), the Excel 2750psi 6HP Honda with the fancy "water broom" (actually pretty handy) I got it at Home Depot.
If there is any air in the lines anywhere, that will cause it to act as you describe. If that's the case, the o-rings will blow out of the wand soon.
If you have public water, then my input probably is not valid because you can be pretty sure that supply will keep up.

[frank_f15]

1st of all check the inlet screen to the washer(where the hose hooks up) AND THEN TAKE THE WAND NOZZEL APART. i had the same problem last year and seems the nozzel plugged up.

[jgbanshee]

I made sure that the filter screen at the hose connection is clean. I took the wand apart twice and didnt find anything wrong. I took the brass valve body off the pump and didnt find anything that would cause a problem. If I connect the water supply hose to the valve and disconnect the wand hose from the valve, with motor OFF I get a fine stream of water shooting out (couple feet) like I did when I did not have a problem. I am not sure that means anything though.